The Experts below are selected from a list of 2295 Experts worldwide ranked by ideXlab platform

Emmanuel Coton - One of the best experts on this subject based on the ideXlab platform.

  • Antifungal lactic acid bacteria combinations as biopreservation tool in dairy products
    2019
    Co-Authors: Marcia Leyva Salas, Jerome Mounier, Emmanuel Coton, Gilles Garric, Florence Valence-bertel, Marielle Harel-oger, Mathilde Lemaître, Anne Thierry
    Abstract:

    Food spoilage is a major issue for the food industry, leading to important food waste and economic losses. In the context of a growing consumers’ demand for clean label foods [1], antifungal cultures are of growing interest as an alternative to chemical preservatives or a complement tool to hurdle technologies. Our aim was to select effective antifungal cultures in fermented dairy products and to identify the compounds most likely involved in their activity. Lactic acid bacteria and propionibacteria strains were screened alone and in combinations in yogurt and cheese models against four major spoilage fungi (Penicillium commune, Mucor racemosus, Galactomyces geotrichum, and Yarrowia lipolytica). Two binary combinations of lactobacilli were then selected to be evaluated in situ as adjunct cultures in Sour Cream and semi-hard cheeses produced at the pilot scale, to evaluate i) their antifungal activity during both challenge tests and shelf life tests, and ii) their impact on organoleptic properties. Four chromatography methods were combined to analyse antifungal compounds.Two binary combinations, A1 and A3 composed of L. plantarum L244 associated with either L. harbinensis L172 or L. rhamnosus CIRM-BIA1113, respectively, were selected from the screening step. Both combinations showed antifungal activity during in situ assays, with a higher efficacy of the combination A1 and a higher overall activity in Sour Cream compared to cheese [2]. In Sour Cream, A1 delayed the growth of P. commune, M. racemosus and R. mucilaginosafor 2-24 days depending of the antifungal culture inoculum, without effect on organoleptic properties at low inoculum (106colony-forming units (CFU)/mL). In semi-hard cheese, A1 delayed the growth of P. commune for 1 to 6 days. Analyses of antifungal compounds revealed that 33 compounds were in significantly higher amount in at least one product inoculated with an antifungal culture compared to the controls [3]. They were present at concentrations below their minimum inhibitory concentration and thus could act in synergy. Our screening approach allowed developing two antifungal combinations that exhibit significant antifungal activity and provide future prospects for use as bioprotective cultures in dairy products. This extensive study also contributes to improve the knowledge about the action mode of antifungal lactobacilli

  • Selection of effective antifungal cultures in fermented dairy products and identification of antifungal metabolites
    2019
    Co-Authors: Marcia Leyva Salas, Jerome Mounier, Emmanuel Coton, Gilles Garric, Florence Valence-bertel, Marie-bernadette Maillard, Anne Thierry
    Abstract:

    Introduction: Antifungal cultures are of growing interest as an alternative to chemical preservatives to reduce food fungal spoilage in the context of a growing consumers’ demand for clean label foods [1]. Our aim was to select strains that exhibit significant antifungal activity in dairy products and to identify the compounds most likely involved in their activity. Materials and methods: Lactic acid bacteria and propionibacteria strains were screened alone and in combinations in yogurt and cheese models against four major spoilage fungi (Penicillium commune, Mucor racemosus, Galactomyces geotrichum, and Yarrowia lipolytica). Two binary combinations of lactobacilli were then selected to be evaluated in situ as adjunct cultures in Sour Cream and semi-hard cheeses produced at a pilot scale to evaluate their antifungal activity during challenge tests and shelf life tests, and their impact on organoleptic properties. Four methods, including liquid and gas chromatography coupled to mass spectrometry, were combined to detect and quantify antifungal compounds. These methods targeted 56 antifungal compounds as well as volatile compounds and were followed by statistical analyses to identify the compounds associated to antifungal activity. Results and discussion: The more effective antifungal culture, composed of two lactobacilli strains, delayed the growth of P. commune, M. racemosus and R. mucilaginosa for 2–24 days on Sour Cream, depending of the antifungal culture inoculum, and the growth of P. commune in semi-hard cheese for 1–6 days. Antifungal cultures had no effect on organoleptic properties at low inoculum level (6 logCFU/mL) [2]. Overall, 53 antifungal compounds were detected, of which 33 were in significantly higher amount in at least one product inoculated with an antifungal culture compared to the controls. They were present at concentrations below their minimum inhibitory concentration and thus could act in synergy. Among them, the most commonly identified were acetic, hydroxyphenyllactic, phenyllactic, 3-phenylpropanoic, 3-(4-hydroxyphenyl)propanoic and 5-oxopyrrolidine-2-carboxylic acids, diacetyl, acetoin, and a yet unidentified volatile compound. Our screening approach allowed developing antifungal combinations that exhibit significant antifungal activity and providing future prospects for use as bioprotective cultures in dairy products. This extensive study also contributes to improve the knowledge about the action mode of antifungal lactobacilli.

  • Potential of lactic acid bacteria combinations as antifungal cultures in pilot scale dairy products.
    2019
    Co-Authors: Marcia Leyva Salas, Jerome Mounier, Anne Thierry, Manon Chatel, Gilles Garric, Florence Valence-bertel, Marielle Harel-oger, Mathilde Lemaître, Emmanuel Coton
    Abstract:

    Consumer's demand for naturally preserved food products is growing and the use of bioprotective cultures is an alternative to chemical preservatives or a complementary tool to hurdle technologies to avoid or delay fungal spoilage of dairy products. To develop antifungal cultures for the dairy product biopreservation, experiments were conducted both in vitro and in situ. Firstly, the antifungal activity of 32 strains of lactic acid bacteria (LAB) and propionibacteria was screened alone, and then on combinations based on 5 selected lactobacilli strains. This screening was performed in yogurt and cheese models against four major spoilage fungi previously isolated from contaminated dairy products (Penicillium commune, Mucor racemosus, Galactomyces geotrichum, and Yarrowia lipolytica). Selected combinations were then tested as adjunct cultures in Sour Cream and semi-hard cheeses produced at a pilot scale to evaluate their antifungal activity during challenge tests against selected fungal targets (P. commune, M. racemosus, and Rhodotorula mucilaginosa) and shelf life tests; and their impact on product organoleptic properties. The screening step allowed selecting two binary combinations, A1 and A3 composed of Lactobacillus plantarum L244 and either Lactobacillus harbinensis L172 or Lactobacillus rhamnosus CIRM-BIA1113, respectively. In situ assays showed that the A1 combination delayed the growth of P. commune, M. racemosus and R. mucilaginosa for 2-24 days on Sour Cream depending of the antifungal culture inoculum, without effect on organoleptic properties at low inoculum (106 colony-forming units (CFU)/mL). Moreover, the A1 and A3 combinations also delayed the growth of P. commune in semi-hard cheese for 1-6 days and 1 day, respectively. Antifungal cultures neither impacted the growth of starter cultures in both Sour Cream and cheese nor the products' pH, although post acidification was observed in Sour Cream supplemented with these combinations at the highest concentrations (2.107 CFU/mL). The combination of both in vitro and in situ screening assays allowed developing 2 antifungal combinations exhibiting significant antifungal activity and providing future prospects for use as bioprotective cultures in dairy products.

  • Selection of Algerian lactic acid bacteria for use as antifungal bioprotective cultures and application in dairy and bakery products
    Food Microbiology, 2019
    Co-Authors: Massinissa Ouiddir, Guessas Bettache, Marcia Leyva Salas, Samira Brahimi, Kihel Mabrouk, Audrey Pawtowski, Christelle Donot, Emmanuel Coton, Jerome Mounier
    Abstract:

    In the context of a demand for “preservative-free” food products, biopreservation appears as a promising alternative to either replace or reduce the use of chemical preservatives. The purpose of this study was to evaluate the antifungal activity of a collection of lactic acid bacteria (n=194), and then to evaluate the applicability and efficacy of selected ones used as bioprotective cultures against mold spoilers in dairy and bakery products. First, lactic acid bacteria were isolated from various Algerian raw milk samples and Amoredj, a traditional fermented product. Secondly, in vitro screening tests against Mucor racemosus UBOCC-A-109155, Penicillium commune UBOCC-A-116003, Yarrowia lipolytica UBOCC-A-216006, Aspergillus tubingensis AN, Aspergillus flavus T5 and Paecilomyces formosus AT allowed for the selection of 3 active strains, namely Lactobacillus plantarum CH1, Lactobacillus paracasei B20 and Leuconostoc mesenteroides L1. In situ tests were then performed to validate their activity in actual products (Sour Cream and Sourdough bread) challenged with fungal spoilers. These tests showed that antifungal LAB could slow the fungal target growth and could be candidates of interest for industrial applications. Finally, organic acids and various antifungal compounds produced in Sour Cream and Sourdough bread by the selected LAB, and thus potentially supporting the observed antifungal activity, were identified and quantified by HPLC and LC-QTOF.

  • Development of antifungal ingredients for dairy products: From in vitro screening to pilot scale application
    Food Microbiology, 2019
    Co-Authors: Lucille Garnier, Audrey Pawtowski, Jerome Mounier, Emmanuel Coton, Anne Thierry, Nicolas Pinon, Benedicte Camier, Manon Chatel, Gilles Garric, Florence Valence-bertel
    Abstract:

    Biopreservation represents a complementary approach to traditional hurdle technologies for reducing microbial contaminants (pathogens and spoilers) in food. In the dairy industry that is concerned by fungal spoilage, biopreservation can also be an alternative to preservatives currently used (e.g. natamycin, potassium sorbate). The aim of this study was to develop antifungal fermentates derived from two dairy substrates using a sequential approach including an in vitro screening followed by an in situ validation. The in vitro screening of the antifungal activity of fermentates derivating from 430 lactic acid bacteria (LAB) (23 species), 70 propionibacteria (4 species) and 198 fungi (87 species) was performed against four major spoilage fungi (Penicillium commune, Mucor racemosus, Galactomyces geotrichum and Yarrowia lipolytica) using a cheese-mimicking model. The most active fermentates were obtained from Lactobacillus brevis, Lactobacillus buchneri, Lactobacillus casei/paracasei and Lactobacillus plantarum among the tested LAB, Propionibacterium jensenii among propionibacteria, and Mucor lanceolatus among the tested fungi. Then, for the 11 most active fermentates, culture conditions were optimized by varying incubation time and temperature in order to enhance their antifungal activity. Finally, the antifungal activity of 3 fermentates of interest obtained from Lactobacillus rhamnosus CIRM-BIA1952, P. jensenii CIRMBIA1774 and M. lanceolatus UBOCC-A-109193 were evaluated in real dairy products (Sour Cream and semi-hard cheese) at a pilot-scale using challenge and durability tests. In parallel, the impact of these ingredients on organoleptic properties of the obtained products was also assessed. In semi-hard cheese, application of the selected fermentates on the cheese surface delayed the growth of spoilage molds for up to 21 days, without any effect on organoleptic properties, P. jensenii CIRM-BIA1774 fermentate being the most active. In Sour Cream, incorporation of the latter fermentate at 2 or 5% yielded a high antifungal activity but was detrimental to the product organoleptic properties. Determination of the concentration limit, compatible with product acceptability, showed that incorporation of this fermentate at 0.4% prevented growth of fungal contaminants in durability tests but had a more limited effect against M. racemosus and P. commune in challenge tests. To our knowledge, this is the first time that the workflow followed in this study, from in vitro screening using dairy matrix to scale-up in cheese and Sour Cream, is applied for production of natural ingredients relying on a large microbial diversity in terms of species and strains. This approach allowed obtaining several antifungal fermentates which are promising candidates for dairy products biopreservation.

Jerome Mounier - One of the best experts on this subject based on the ideXlab platform.

  • Antifungal lactic acid bacteria combinations as biopreservation tool in dairy products
    2019
    Co-Authors: Marcia Leyva Salas, Jerome Mounier, Emmanuel Coton, Gilles Garric, Florence Valence-bertel, Marielle Harel-oger, Mathilde Lemaître, Anne Thierry
    Abstract:

    Food spoilage is a major issue for the food industry, leading to important food waste and economic losses. In the context of a growing consumers’ demand for clean label foods [1], antifungal cultures are of growing interest as an alternative to chemical preservatives or a complement tool to hurdle technologies. Our aim was to select effective antifungal cultures in fermented dairy products and to identify the compounds most likely involved in their activity. Lactic acid bacteria and propionibacteria strains were screened alone and in combinations in yogurt and cheese models against four major spoilage fungi (Penicillium commune, Mucor racemosus, Galactomyces geotrichum, and Yarrowia lipolytica). Two binary combinations of lactobacilli were then selected to be evaluated in situ as adjunct cultures in Sour Cream and semi-hard cheeses produced at the pilot scale, to evaluate i) their antifungal activity during both challenge tests and shelf life tests, and ii) their impact on organoleptic properties. Four chromatography methods were combined to analyse antifungal compounds.Two binary combinations, A1 and A3 composed of L. plantarum L244 associated with either L. harbinensis L172 or L. rhamnosus CIRM-BIA1113, respectively, were selected from the screening step. Both combinations showed antifungal activity during in situ assays, with a higher efficacy of the combination A1 and a higher overall activity in Sour Cream compared to cheese [2]. In Sour Cream, A1 delayed the growth of P. commune, M. racemosus and R. mucilaginosafor 2-24 days depending of the antifungal culture inoculum, without effect on organoleptic properties at low inoculum (106colony-forming units (CFU)/mL). In semi-hard cheese, A1 delayed the growth of P. commune for 1 to 6 days. Analyses of antifungal compounds revealed that 33 compounds were in significantly higher amount in at least one product inoculated with an antifungal culture compared to the controls [3]. They were present at concentrations below their minimum inhibitory concentration and thus could act in synergy. Our screening approach allowed developing two antifungal combinations that exhibit significant antifungal activity and provide future prospects for use as bioprotective cultures in dairy products. This extensive study also contributes to improve the knowledge about the action mode of antifungal lactobacilli

  • Selection of effective antifungal cultures in fermented dairy products and identification of antifungal metabolites
    2019
    Co-Authors: Marcia Leyva Salas, Jerome Mounier, Emmanuel Coton, Gilles Garric, Florence Valence-bertel, Marie-bernadette Maillard, Anne Thierry
    Abstract:

    Introduction: Antifungal cultures are of growing interest as an alternative to chemical preservatives to reduce food fungal spoilage in the context of a growing consumers’ demand for clean label foods [1]. Our aim was to select strains that exhibit significant antifungal activity in dairy products and to identify the compounds most likely involved in their activity. Materials and methods: Lactic acid bacteria and propionibacteria strains were screened alone and in combinations in yogurt and cheese models against four major spoilage fungi (Penicillium commune, Mucor racemosus, Galactomyces geotrichum, and Yarrowia lipolytica). Two binary combinations of lactobacilli were then selected to be evaluated in situ as adjunct cultures in Sour Cream and semi-hard cheeses produced at a pilot scale to evaluate their antifungal activity during challenge tests and shelf life tests, and their impact on organoleptic properties. Four methods, including liquid and gas chromatography coupled to mass spectrometry, were combined to detect and quantify antifungal compounds. These methods targeted 56 antifungal compounds as well as volatile compounds and were followed by statistical analyses to identify the compounds associated to antifungal activity. Results and discussion: The more effective antifungal culture, composed of two lactobacilli strains, delayed the growth of P. commune, M. racemosus and R. mucilaginosa for 2–24 days on Sour Cream, depending of the antifungal culture inoculum, and the growth of P. commune in semi-hard cheese for 1–6 days. Antifungal cultures had no effect on organoleptic properties at low inoculum level (6 logCFU/mL) [2]. Overall, 53 antifungal compounds were detected, of which 33 were in significantly higher amount in at least one product inoculated with an antifungal culture compared to the controls. They were present at concentrations below their minimum inhibitory concentration and thus could act in synergy. Among them, the most commonly identified were acetic, hydroxyphenyllactic, phenyllactic, 3-phenylpropanoic, 3-(4-hydroxyphenyl)propanoic and 5-oxopyrrolidine-2-carboxylic acids, diacetyl, acetoin, and a yet unidentified volatile compound. Our screening approach allowed developing antifungal combinations that exhibit significant antifungal activity and providing future prospects for use as bioprotective cultures in dairy products. This extensive study also contributes to improve the knowledge about the action mode of antifungal lactobacilli.

  • Potential of lactic acid bacteria combinations as antifungal cultures in pilot scale dairy products.
    2019
    Co-Authors: Marcia Leyva Salas, Jerome Mounier, Anne Thierry, Manon Chatel, Gilles Garric, Florence Valence-bertel, Marielle Harel-oger, Mathilde Lemaître, Emmanuel Coton
    Abstract:

    Consumer's demand for naturally preserved food products is growing and the use of bioprotective cultures is an alternative to chemical preservatives or a complementary tool to hurdle technologies to avoid or delay fungal spoilage of dairy products. To develop antifungal cultures for the dairy product biopreservation, experiments were conducted both in vitro and in situ. Firstly, the antifungal activity of 32 strains of lactic acid bacteria (LAB) and propionibacteria was screened alone, and then on combinations based on 5 selected lactobacilli strains. This screening was performed in yogurt and cheese models against four major spoilage fungi previously isolated from contaminated dairy products (Penicillium commune, Mucor racemosus, Galactomyces geotrichum, and Yarrowia lipolytica). Selected combinations were then tested as adjunct cultures in Sour Cream and semi-hard cheeses produced at a pilot scale to evaluate their antifungal activity during challenge tests against selected fungal targets (P. commune, M. racemosus, and Rhodotorula mucilaginosa) and shelf life tests; and their impact on product organoleptic properties. The screening step allowed selecting two binary combinations, A1 and A3 composed of Lactobacillus plantarum L244 and either Lactobacillus harbinensis L172 or Lactobacillus rhamnosus CIRM-BIA1113, respectively. In situ assays showed that the A1 combination delayed the growth of P. commune, M. racemosus and R. mucilaginosa for 2-24 days on Sour Cream depending of the antifungal culture inoculum, without effect on organoleptic properties at low inoculum (106 colony-forming units (CFU)/mL). Moreover, the A1 and A3 combinations also delayed the growth of P. commune in semi-hard cheese for 1-6 days and 1 day, respectively. Antifungal cultures neither impacted the growth of starter cultures in both Sour Cream and cheese nor the products' pH, although post acidification was observed in Sour Cream supplemented with these combinations at the highest concentrations (2.107 CFU/mL). The combination of both in vitro and in situ screening assays allowed developing 2 antifungal combinations exhibiting significant antifungal activity and providing future prospects for use as bioprotective cultures in dairy products.

  • Selection of Algerian lactic acid bacteria for use as antifungal bioprotective cultures and application in dairy and bakery products
    Food Microbiology, 2019
    Co-Authors: Massinissa Ouiddir, Guessas Bettache, Marcia Leyva Salas, Samira Brahimi, Kihel Mabrouk, Audrey Pawtowski, Christelle Donot, Emmanuel Coton, Jerome Mounier
    Abstract:

    In the context of a demand for “preservative-free” food products, biopreservation appears as a promising alternative to either replace or reduce the use of chemical preservatives. The purpose of this study was to evaluate the antifungal activity of a collection of lactic acid bacteria (n=194), and then to evaluate the applicability and efficacy of selected ones used as bioprotective cultures against mold spoilers in dairy and bakery products. First, lactic acid bacteria were isolated from various Algerian raw milk samples and Amoredj, a traditional fermented product. Secondly, in vitro screening tests against Mucor racemosus UBOCC-A-109155, Penicillium commune UBOCC-A-116003, Yarrowia lipolytica UBOCC-A-216006, Aspergillus tubingensis AN, Aspergillus flavus T5 and Paecilomyces formosus AT allowed for the selection of 3 active strains, namely Lactobacillus plantarum CH1, Lactobacillus paracasei B20 and Leuconostoc mesenteroides L1. In situ tests were then performed to validate their activity in actual products (Sour Cream and Sourdough bread) challenged with fungal spoilers. These tests showed that antifungal LAB could slow the fungal target growth and could be candidates of interest for industrial applications. Finally, organic acids and various antifungal compounds produced in Sour Cream and Sourdough bread by the selected LAB, and thus potentially supporting the observed antifungal activity, were identified and quantified by HPLC and LC-QTOF.

  • Development of antifungal ingredients for dairy products: From in vitro screening to pilot scale application
    Food Microbiology, 2019
    Co-Authors: Lucille Garnier, Audrey Pawtowski, Jerome Mounier, Emmanuel Coton, Anne Thierry, Nicolas Pinon, Benedicte Camier, Manon Chatel, Gilles Garric, Florence Valence-bertel
    Abstract:

    Biopreservation represents a complementary approach to traditional hurdle technologies for reducing microbial contaminants (pathogens and spoilers) in food. In the dairy industry that is concerned by fungal spoilage, biopreservation can also be an alternative to preservatives currently used (e.g. natamycin, potassium sorbate). The aim of this study was to develop antifungal fermentates derived from two dairy substrates using a sequential approach including an in vitro screening followed by an in situ validation. The in vitro screening of the antifungal activity of fermentates derivating from 430 lactic acid bacteria (LAB) (23 species), 70 propionibacteria (4 species) and 198 fungi (87 species) was performed against four major spoilage fungi (Penicillium commune, Mucor racemosus, Galactomyces geotrichum and Yarrowia lipolytica) using a cheese-mimicking model. The most active fermentates were obtained from Lactobacillus brevis, Lactobacillus buchneri, Lactobacillus casei/paracasei and Lactobacillus plantarum among the tested LAB, Propionibacterium jensenii among propionibacteria, and Mucor lanceolatus among the tested fungi. Then, for the 11 most active fermentates, culture conditions were optimized by varying incubation time and temperature in order to enhance their antifungal activity. Finally, the antifungal activity of 3 fermentates of interest obtained from Lactobacillus rhamnosus CIRM-BIA1952, P. jensenii CIRMBIA1774 and M. lanceolatus UBOCC-A-109193 were evaluated in real dairy products (Sour Cream and semi-hard cheese) at a pilot-scale using challenge and durability tests. In parallel, the impact of these ingredients on organoleptic properties of the obtained products was also assessed. In semi-hard cheese, application of the selected fermentates on the cheese surface delayed the growth of spoilage molds for up to 21 days, without any effect on organoleptic properties, P. jensenii CIRM-BIA1774 fermentate being the most active. In Sour Cream, incorporation of the latter fermentate at 2 or 5% yielded a high antifungal activity but was detrimental to the product organoleptic properties. Determination of the concentration limit, compatible with product acceptability, showed that incorporation of this fermentate at 0.4% prevented growth of fungal contaminants in durability tests but had a more limited effect against M. racemosus and P. commune in challenge tests. To our knowledge, this is the first time that the workflow followed in this study, from in vitro screening using dairy matrix to scale-up in cheese and Sour Cream, is applied for production of natural ingredients relying on a large microbial diversity in terms of species and strains. This approach allowed obtaining several antifungal fermentates which are promising candidates for dairy products biopreservation.

Florence Valence-bertel - One of the best experts on this subject based on the ideXlab platform.

  • Antifungal lactic acid bacteria combinations as biopreservation tool in dairy products
    2019
    Co-Authors: Marcia Leyva Salas, Jerome Mounier, Emmanuel Coton, Gilles Garric, Florence Valence-bertel, Marielle Harel-oger, Mathilde Lemaître, Anne Thierry
    Abstract:

    Food spoilage is a major issue for the food industry, leading to important food waste and economic losses. In the context of a growing consumers’ demand for clean label foods [1], antifungal cultures are of growing interest as an alternative to chemical preservatives or a complement tool to hurdle technologies. Our aim was to select effective antifungal cultures in fermented dairy products and to identify the compounds most likely involved in their activity. Lactic acid bacteria and propionibacteria strains were screened alone and in combinations in yogurt and cheese models against four major spoilage fungi (Penicillium commune, Mucor racemosus, Galactomyces geotrichum, and Yarrowia lipolytica). Two binary combinations of lactobacilli were then selected to be evaluated in situ as adjunct cultures in Sour Cream and semi-hard cheeses produced at the pilot scale, to evaluate i) their antifungal activity during both challenge tests and shelf life tests, and ii) their impact on organoleptic properties. Four chromatography methods were combined to analyse antifungal compounds.Two binary combinations, A1 and A3 composed of L. plantarum L244 associated with either L. harbinensis L172 or L. rhamnosus CIRM-BIA1113, respectively, were selected from the screening step. Both combinations showed antifungal activity during in situ assays, with a higher efficacy of the combination A1 and a higher overall activity in Sour Cream compared to cheese [2]. In Sour Cream, A1 delayed the growth of P. commune, M. racemosus and R. mucilaginosafor 2-24 days depending of the antifungal culture inoculum, without effect on organoleptic properties at low inoculum (106colony-forming units (CFU)/mL). In semi-hard cheese, A1 delayed the growth of P. commune for 1 to 6 days. Analyses of antifungal compounds revealed that 33 compounds were in significantly higher amount in at least one product inoculated with an antifungal culture compared to the controls [3]. They were present at concentrations below their minimum inhibitory concentration and thus could act in synergy. Our screening approach allowed developing two antifungal combinations that exhibit significant antifungal activity and provide future prospects for use as bioprotective cultures in dairy products. This extensive study also contributes to improve the knowledge about the action mode of antifungal lactobacilli

  • Selection of effective antifungal cultures in fermented dairy products and identification of antifungal metabolites
    2019
    Co-Authors: Marcia Leyva Salas, Jerome Mounier, Emmanuel Coton, Gilles Garric, Florence Valence-bertel, Marie-bernadette Maillard, Anne Thierry
    Abstract:

    Introduction: Antifungal cultures are of growing interest as an alternative to chemical preservatives to reduce food fungal spoilage in the context of a growing consumers’ demand for clean label foods [1]. Our aim was to select strains that exhibit significant antifungal activity in dairy products and to identify the compounds most likely involved in their activity. Materials and methods: Lactic acid bacteria and propionibacteria strains were screened alone and in combinations in yogurt and cheese models against four major spoilage fungi (Penicillium commune, Mucor racemosus, Galactomyces geotrichum, and Yarrowia lipolytica). Two binary combinations of lactobacilli were then selected to be evaluated in situ as adjunct cultures in Sour Cream and semi-hard cheeses produced at a pilot scale to evaluate their antifungal activity during challenge tests and shelf life tests, and their impact on organoleptic properties. Four methods, including liquid and gas chromatography coupled to mass spectrometry, were combined to detect and quantify antifungal compounds. These methods targeted 56 antifungal compounds as well as volatile compounds and were followed by statistical analyses to identify the compounds associated to antifungal activity. Results and discussion: The more effective antifungal culture, composed of two lactobacilli strains, delayed the growth of P. commune, M. racemosus and R. mucilaginosa for 2–24 days on Sour Cream, depending of the antifungal culture inoculum, and the growth of P. commune in semi-hard cheese for 1–6 days. Antifungal cultures had no effect on organoleptic properties at low inoculum level (6 logCFU/mL) [2]. Overall, 53 antifungal compounds were detected, of which 33 were in significantly higher amount in at least one product inoculated with an antifungal culture compared to the controls. They were present at concentrations below their minimum inhibitory concentration and thus could act in synergy. Among them, the most commonly identified were acetic, hydroxyphenyllactic, phenyllactic, 3-phenylpropanoic, 3-(4-hydroxyphenyl)propanoic and 5-oxopyrrolidine-2-carboxylic acids, diacetyl, acetoin, and a yet unidentified volatile compound. Our screening approach allowed developing antifungal combinations that exhibit significant antifungal activity and providing future prospects for use as bioprotective cultures in dairy products. This extensive study also contributes to improve the knowledge about the action mode of antifungal lactobacilli.

  • Potential of lactic acid bacteria combinations as antifungal cultures in pilot scale dairy products.
    2019
    Co-Authors: Marcia Leyva Salas, Jerome Mounier, Anne Thierry, Manon Chatel, Gilles Garric, Florence Valence-bertel, Marielle Harel-oger, Mathilde Lemaître, Emmanuel Coton
    Abstract:

    Consumer's demand for naturally preserved food products is growing and the use of bioprotective cultures is an alternative to chemical preservatives or a complementary tool to hurdle technologies to avoid or delay fungal spoilage of dairy products. To develop antifungal cultures for the dairy product biopreservation, experiments were conducted both in vitro and in situ. Firstly, the antifungal activity of 32 strains of lactic acid bacteria (LAB) and propionibacteria was screened alone, and then on combinations based on 5 selected lactobacilli strains. This screening was performed in yogurt and cheese models against four major spoilage fungi previously isolated from contaminated dairy products (Penicillium commune, Mucor racemosus, Galactomyces geotrichum, and Yarrowia lipolytica). Selected combinations were then tested as adjunct cultures in Sour Cream and semi-hard cheeses produced at a pilot scale to evaluate their antifungal activity during challenge tests against selected fungal targets (P. commune, M. racemosus, and Rhodotorula mucilaginosa) and shelf life tests; and their impact on product organoleptic properties. The screening step allowed selecting two binary combinations, A1 and A3 composed of Lactobacillus plantarum L244 and either Lactobacillus harbinensis L172 or Lactobacillus rhamnosus CIRM-BIA1113, respectively. In situ assays showed that the A1 combination delayed the growth of P. commune, M. racemosus and R. mucilaginosa for 2-24 days on Sour Cream depending of the antifungal culture inoculum, without effect on organoleptic properties at low inoculum (106 colony-forming units (CFU)/mL). Moreover, the A1 and A3 combinations also delayed the growth of P. commune in semi-hard cheese for 1-6 days and 1 day, respectively. Antifungal cultures neither impacted the growth of starter cultures in both Sour Cream and cheese nor the products' pH, although post acidification was observed in Sour Cream supplemented with these combinations at the highest concentrations (2.107 CFU/mL). The combination of both in vitro and in situ screening assays allowed developing 2 antifungal combinations exhibiting significant antifungal activity and providing future prospects for use as bioprotective cultures in dairy products.

  • Development of antifungal ingredients for dairy products: From in vitro screening to pilot scale application
    Food Microbiology, 2019
    Co-Authors: Lucille Garnier, Audrey Pawtowski, Jerome Mounier, Emmanuel Coton, Anne Thierry, Nicolas Pinon, Benedicte Camier, Manon Chatel, Gilles Garric, Florence Valence-bertel
    Abstract:

    Biopreservation represents a complementary approach to traditional hurdle technologies for reducing microbial contaminants (pathogens and spoilers) in food. In the dairy industry that is concerned by fungal spoilage, biopreservation can also be an alternative to preservatives currently used (e.g. natamycin, potassium sorbate). The aim of this study was to develop antifungal fermentates derived from two dairy substrates using a sequential approach including an in vitro screening followed by an in situ validation. The in vitro screening of the antifungal activity of fermentates derivating from 430 lactic acid bacteria (LAB) (23 species), 70 propionibacteria (4 species) and 198 fungi (87 species) was performed against four major spoilage fungi (Penicillium commune, Mucor racemosus, Galactomyces geotrichum and Yarrowia lipolytica) using a cheese-mimicking model. The most active fermentates were obtained from Lactobacillus brevis, Lactobacillus buchneri, Lactobacillus casei/paracasei and Lactobacillus plantarum among the tested LAB, Propionibacterium jensenii among propionibacteria, and Mucor lanceolatus among the tested fungi. Then, for the 11 most active fermentates, culture conditions were optimized by varying incubation time and temperature in order to enhance their antifungal activity. Finally, the antifungal activity of 3 fermentates of interest obtained from Lactobacillus rhamnosus CIRM-BIA1952, P. jensenii CIRMBIA1774 and M. lanceolatus UBOCC-A-109193 were evaluated in real dairy products (Sour Cream and semi-hard cheese) at a pilot-scale using challenge and durability tests. In parallel, the impact of these ingredients on organoleptic properties of the obtained products was also assessed. In semi-hard cheese, application of the selected fermentates on the cheese surface delayed the growth of spoilage molds for up to 21 days, without any effect on organoleptic properties, P. jensenii CIRM-BIA1774 fermentate being the most active. In Sour Cream, incorporation of the latter fermentate at 2 or 5% yielded a high antifungal activity but was detrimental to the product organoleptic properties. Determination of the concentration limit, compatible with product acceptability, showed that incorporation of this fermentate at 0.4% prevented growth of fungal contaminants in durability tests but had a more limited effect against M. racemosus and P. commune in challenge tests. To our knowledge, this is the first time that the workflow followed in this study, from in vitro screening using dairy matrix to scale-up in cheese and Sour Cream, is applied for production of natural ingredients relying on a large microbial diversity in terms of species and strains. This approach allowed obtaining several antifungal fermentates which are promising candidates for dairy products biopreservation.

  • Composés potentiellement support de l’activité antifongique de cultures bioprotectrices dans des produits laitiers
    2018
    Co-Authors: Marcia Leyva Salas, Jerome Mounier, Emmanuel Coton, Florence Valence-bertel, Marie-bernadette Maillard, Anne Thierry
    Abstract:

    Fungi are commonly responsible for dairy product spoilage, which leads to substantial economic losses for the dairy industry as well as consumer dissatisfaction. Lactic acid bacteria can play an active role in the bioprotection of fermented dairy product, by producing a large range of antifungal metabolites. In a previous study, 3 binary combinations of lactobacilli strains were selected from a screening of the antifungal activity of 32 strains tested as adjunct cultures in yogurt and cheese models and the applicability of 2 of them in dairy products was validated at the pilot scale in Sour Cream and semi-hard cheese. Thus, the aim of the present study was to investigate the compounds produced by these antifungal cultures in these dairy products with a potential role in the observed antifungal activity. Using four different analytical methods including high performance liquid chromatography and gas chromatography combined or not with mass spectrometry, 53 compounds with known antifungal activity were detected in at least one of the four dairy products analyzed. Each antifungal culture produced a cocktail of 2 to 27 compounds, depending on the product. Acetic acid, diacetyl, hydroxyphenyllactic acid, pyruvic acid, phenyllactic acid, succinic acid, decanoic acid and some long-chain unsaturated fatty acids were the most commonly identified compounds. Their concentrations markedly differed according to the considered dairy product. Lactic, acetic, and citric acids were the most abundant compounds, while most of the other compounds were present in concentrations

Anne Thierry - One of the best experts on this subject based on the ideXlab platform.

  • Antifungal lactic acid bacteria combinations as biopreservation tool in dairy products
    2019
    Co-Authors: Marcia Leyva Salas, Jerome Mounier, Emmanuel Coton, Gilles Garric, Florence Valence-bertel, Marielle Harel-oger, Mathilde Lemaître, Anne Thierry
    Abstract:

    Food spoilage is a major issue for the food industry, leading to important food waste and economic losses. In the context of a growing consumers’ demand for clean label foods [1], antifungal cultures are of growing interest as an alternative to chemical preservatives or a complement tool to hurdle technologies. Our aim was to select effective antifungal cultures in fermented dairy products and to identify the compounds most likely involved in their activity. Lactic acid bacteria and propionibacteria strains were screened alone and in combinations in yogurt and cheese models against four major spoilage fungi (Penicillium commune, Mucor racemosus, Galactomyces geotrichum, and Yarrowia lipolytica). Two binary combinations of lactobacilli were then selected to be evaluated in situ as adjunct cultures in Sour Cream and semi-hard cheeses produced at the pilot scale, to evaluate i) their antifungal activity during both challenge tests and shelf life tests, and ii) their impact on organoleptic properties. Four chromatography methods were combined to analyse antifungal compounds.Two binary combinations, A1 and A3 composed of L. plantarum L244 associated with either L. harbinensis L172 or L. rhamnosus CIRM-BIA1113, respectively, were selected from the screening step. Both combinations showed antifungal activity during in situ assays, with a higher efficacy of the combination A1 and a higher overall activity in Sour Cream compared to cheese [2]. In Sour Cream, A1 delayed the growth of P. commune, M. racemosus and R. mucilaginosafor 2-24 days depending of the antifungal culture inoculum, without effect on organoleptic properties at low inoculum (106colony-forming units (CFU)/mL). In semi-hard cheese, A1 delayed the growth of P. commune for 1 to 6 days. Analyses of antifungal compounds revealed that 33 compounds were in significantly higher amount in at least one product inoculated with an antifungal culture compared to the controls [3]. They were present at concentrations below their minimum inhibitory concentration and thus could act in synergy. Our screening approach allowed developing two antifungal combinations that exhibit significant antifungal activity and provide future prospects for use as bioprotective cultures in dairy products. This extensive study also contributes to improve the knowledge about the action mode of antifungal lactobacilli

  • Selection of effective antifungal cultures in fermented dairy products and identification of antifungal metabolites
    2019
    Co-Authors: Marcia Leyva Salas, Jerome Mounier, Emmanuel Coton, Gilles Garric, Florence Valence-bertel, Marie-bernadette Maillard, Anne Thierry
    Abstract:

    Introduction: Antifungal cultures are of growing interest as an alternative to chemical preservatives to reduce food fungal spoilage in the context of a growing consumers’ demand for clean label foods [1]. Our aim was to select strains that exhibit significant antifungal activity in dairy products and to identify the compounds most likely involved in their activity. Materials and methods: Lactic acid bacteria and propionibacteria strains were screened alone and in combinations in yogurt and cheese models against four major spoilage fungi (Penicillium commune, Mucor racemosus, Galactomyces geotrichum, and Yarrowia lipolytica). Two binary combinations of lactobacilli were then selected to be evaluated in situ as adjunct cultures in Sour Cream and semi-hard cheeses produced at a pilot scale to evaluate their antifungal activity during challenge tests and shelf life tests, and their impact on organoleptic properties. Four methods, including liquid and gas chromatography coupled to mass spectrometry, were combined to detect and quantify antifungal compounds. These methods targeted 56 antifungal compounds as well as volatile compounds and were followed by statistical analyses to identify the compounds associated to antifungal activity. Results and discussion: The more effective antifungal culture, composed of two lactobacilli strains, delayed the growth of P. commune, M. racemosus and R. mucilaginosa for 2–24 days on Sour Cream, depending of the antifungal culture inoculum, and the growth of P. commune in semi-hard cheese for 1–6 days. Antifungal cultures had no effect on organoleptic properties at low inoculum level (6 logCFU/mL) [2]. Overall, 53 antifungal compounds were detected, of which 33 were in significantly higher amount in at least one product inoculated with an antifungal culture compared to the controls. They were present at concentrations below their minimum inhibitory concentration and thus could act in synergy. Among them, the most commonly identified were acetic, hydroxyphenyllactic, phenyllactic, 3-phenylpropanoic, 3-(4-hydroxyphenyl)propanoic and 5-oxopyrrolidine-2-carboxylic acids, diacetyl, acetoin, and a yet unidentified volatile compound. Our screening approach allowed developing antifungal combinations that exhibit significant antifungal activity and providing future prospects for use as bioprotective cultures in dairy products. This extensive study also contributes to improve the knowledge about the action mode of antifungal lactobacilli.

  • Potential of lactic acid bacteria combinations as antifungal cultures in pilot scale dairy products.
    2019
    Co-Authors: Marcia Leyva Salas, Jerome Mounier, Anne Thierry, Manon Chatel, Gilles Garric, Florence Valence-bertel, Marielle Harel-oger, Mathilde Lemaître, Emmanuel Coton
    Abstract:

    Consumer's demand for naturally preserved food products is growing and the use of bioprotective cultures is an alternative to chemical preservatives or a complementary tool to hurdle technologies to avoid or delay fungal spoilage of dairy products. To develop antifungal cultures for the dairy product biopreservation, experiments were conducted both in vitro and in situ. Firstly, the antifungal activity of 32 strains of lactic acid bacteria (LAB) and propionibacteria was screened alone, and then on combinations based on 5 selected lactobacilli strains. This screening was performed in yogurt and cheese models against four major spoilage fungi previously isolated from contaminated dairy products (Penicillium commune, Mucor racemosus, Galactomyces geotrichum, and Yarrowia lipolytica). Selected combinations were then tested as adjunct cultures in Sour Cream and semi-hard cheeses produced at a pilot scale to evaluate their antifungal activity during challenge tests against selected fungal targets (P. commune, M. racemosus, and Rhodotorula mucilaginosa) and shelf life tests; and their impact on product organoleptic properties. The screening step allowed selecting two binary combinations, A1 and A3 composed of Lactobacillus plantarum L244 and either Lactobacillus harbinensis L172 or Lactobacillus rhamnosus CIRM-BIA1113, respectively. In situ assays showed that the A1 combination delayed the growth of P. commune, M. racemosus and R. mucilaginosa for 2-24 days on Sour Cream depending of the antifungal culture inoculum, without effect on organoleptic properties at low inoculum (106 colony-forming units (CFU)/mL). Moreover, the A1 and A3 combinations also delayed the growth of P. commune in semi-hard cheese for 1-6 days and 1 day, respectively. Antifungal cultures neither impacted the growth of starter cultures in both Sour Cream and cheese nor the products' pH, although post acidification was observed in Sour Cream supplemented with these combinations at the highest concentrations (2.107 CFU/mL). The combination of both in vitro and in situ screening assays allowed developing 2 antifungal combinations exhibiting significant antifungal activity and providing future prospects for use as bioprotective cultures in dairy products.

  • Development of antifungal ingredients for dairy products: From in vitro screening to pilot scale application
    Food Microbiology, 2019
    Co-Authors: Lucille Garnier, Audrey Pawtowski, Jerome Mounier, Emmanuel Coton, Anne Thierry, Nicolas Pinon, Benedicte Camier, Manon Chatel, Gilles Garric, Florence Valence-bertel
    Abstract:

    Biopreservation represents a complementary approach to traditional hurdle technologies for reducing microbial contaminants (pathogens and spoilers) in food. In the dairy industry that is concerned by fungal spoilage, biopreservation can also be an alternative to preservatives currently used (e.g. natamycin, potassium sorbate). The aim of this study was to develop antifungal fermentates derived from two dairy substrates using a sequential approach including an in vitro screening followed by an in situ validation. The in vitro screening of the antifungal activity of fermentates derivating from 430 lactic acid bacteria (LAB) (23 species), 70 propionibacteria (4 species) and 198 fungi (87 species) was performed against four major spoilage fungi (Penicillium commune, Mucor racemosus, Galactomyces geotrichum and Yarrowia lipolytica) using a cheese-mimicking model. The most active fermentates were obtained from Lactobacillus brevis, Lactobacillus buchneri, Lactobacillus casei/paracasei and Lactobacillus plantarum among the tested LAB, Propionibacterium jensenii among propionibacteria, and Mucor lanceolatus among the tested fungi. Then, for the 11 most active fermentates, culture conditions were optimized by varying incubation time and temperature in order to enhance their antifungal activity. Finally, the antifungal activity of 3 fermentates of interest obtained from Lactobacillus rhamnosus CIRM-BIA1952, P. jensenii CIRMBIA1774 and M. lanceolatus UBOCC-A-109193 were evaluated in real dairy products (Sour Cream and semi-hard cheese) at a pilot-scale using challenge and durability tests. In parallel, the impact of these ingredients on organoleptic properties of the obtained products was also assessed. In semi-hard cheese, application of the selected fermentates on the cheese surface delayed the growth of spoilage molds for up to 21 days, without any effect on organoleptic properties, P. jensenii CIRM-BIA1774 fermentate being the most active. In Sour Cream, incorporation of the latter fermentate at 2 or 5% yielded a high antifungal activity but was detrimental to the product organoleptic properties. Determination of the concentration limit, compatible with product acceptability, showed that incorporation of this fermentate at 0.4% prevented growth of fungal contaminants in durability tests but had a more limited effect against M. racemosus and P. commune in challenge tests. To our knowledge, this is the first time that the workflow followed in this study, from in vitro screening using dairy matrix to scale-up in cheese and Sour Cream, is applied for production of natural ingredients relying on a large microbial diversity in terms of species and strains. This approach allowed obtaining several antifungal fermentates which are promising candidates for dairy products biopreservation.

  • Composés potentiellement support de l’activité antifongique de cultures bioprotectrices dans des produits laitiers
    2018
    Co-Authors: Marcia Leyva Salas, Jerome Mounier, Emmanuel Coton, Florence Valence-bertel, Marie-bernadette Maillard, Anne Thierry
    Abstract:

    Fungi are commonly responsible for dairy product spoilage, which leads to substantial economic losses for the dairy industry as well as consumer dissatisfaction. Lactic acid bacteria can play an active role in the bioprotection of fermented dairy product, by producing a large range of antifungal metabolites. In a previous study, 3 binary combinations of lactobacilli strains were selected from a screening of the antifungal activity of 32 strains tested as adjunct cultures in yogurt and cheese models and the applicability of 2 of them in dairy products was validated at the pilot scale in Sour Cream and semi-hard cheese. Thus, the aim of the present study was to investigate the compounds produced by these antifungal cultures in these dairy products with a potential role in the observed antifungal activity. Using four different analytical methods including high performance liquid chromatography and gas chromatography combined or not with mass spectrometry, 53 compounds with known antifungal activity were detected in at least one of the four dairy products analyzed. Each antifungal culture produced a cocktail of 2 to 27 compounds, depending on the product. Acetic acid, diacetyl, hydroxyphenyllactic acid, pyruvic acid, phenyllactic acid, succinic acid, decanoic acid and some long-chain unsaturated fatty acids were the most commonly identified compounds. Their concentrations markedly differed according to the considered dairy product. Lactic, acetic, and citric acids were the most abundant compounds, while most of the other compounds were present in concentrations

Marcia Leyva Salas - One of the best experts on this subject based on the ideXlab platform.

  • Antifungal lactic acid bacteria combinations as biopreservation tool in dairy products
    2019
    Co-Authors: Marcia Leyva Salas, Jerome Mounier, Emmanuel Coton, Gilles Garric, Florence Valence-bertel, Marielle Harel-oger, Mathilde Lemaître, Anne Thierry
    Abstract:

    Food spoilage is a major issue for the food industry, leading to important food waste and economic losses. In the context of a growing consumers’ demand for clean label foods [1], antifungal cultures are of growing interest as an alternative to chemical preservatives or a complement tool to hurdle technologies. Our aim was to select effective antifungal cultures in fermented dairy products and to identify the compounds most likely involved in their activity. Lactic acid bacteria and propionibacteria strains were screened alone and in combinations in yogurt and cheese models against four major spoilage fungi (Penicillium commune, Mucor racemosus, Galactomyces geotrichum, and Yarrowia lipolytica). Two binary combinations of lactobacilli were then selected to be evaluated in situ as adjunct cultures in Sour Cream and semi-hard cheeses produced at the pilot scale, to evaluate i) their antifungal activity during both challenge tests and shelf life tests, and ii) their impact on organoleptic properties. Four chromatography methods were combined to analyse antifungal compounds.Two binary combinations, A1 and A3 composed of L. plantarum L244 associated with either L. harbinensis L172 or L. rhamnosus CIRM-BIA1113, respectively, were selected from the screening step. Both combinations showed antifungal activity during in situ assays, with a higher efficacy of the combination A1 and a higher overall activity in Sour Cream compared to cheese [2]. In Sour Cream, A1 delayed the growth of P. commune, M. racemosus and R. mucilaginosafor 2-24 days depending of the antifungal culture inoculum, without effect on organoleptic properties at low inoculum (106colony-forming units (CFU)/mL). In semi-hard cheese, A1 delayed the growth of P. commune for 1 to 6 days. Analyses of antifungal compounds revealed that 33 compounds were in significantly higher amount in at least one product inoculated with an antifungal culture compared to the controls [3]. They were present at concentrations below their minimum inhibitory concentration and thus could act in synergy. Our screening approach allowed developing two antifungal combinations that exhibit significant antifungal activity and provide future prospects for use as bioprotective cultures in dairy products. This extensive study also contributes to improve the knowledge about the action mode of antifungal lactobacilli

  • Selection of effective antifungal cultures in fermented dairy products and identification of antifungal metabolites
    2019
    Co-Authors: Marcia Leyva Salas, Jerome Mounier, Emmanuel Coton, Gilles Garric, Florence Valence-bertel, Marie-bernadette Maillard, Anne Thierry
    Abstract:

    Introduction: Antifungal cultures are of growing interest as an alternative to chemical preservatives to reduce food fungal spoilage in the context of a growing consumers’ demand for clean label foods [1]. Our aim was to select strains that exhibit significant antifungal activity in dairy products and to identify the compounds most likely involved in their activity. Materials and methods: Lactic acid bacteria and propionibacteria strains were screened alone and in combinations in yogurt and cheese models against four major spoilage fungi (Penicillium commune, Mucor racemosus, Galactomyces geotrichum, and Yarrowia lipolytica). Two binary combinations of lactobacilli were then selected to be evaluated in situ as adjunct cultures in Sour Cream and semi-hard cheeses produced at a pilot scale to evaluate their antifungal activity during challenge tests and shelf life tests, and their impact on organoleptic properties. Four methods, including liquid and gas chromatography coupled to mass spectrometry, were combined to detect and quantify antifungal compounds. These methods targeted 56 antifungal compounds as well as volatile compounds and were followed by statistical analyses to identify the compounds associated to antifungal activity. Results and discussion: The more effective antifungal culture, composed of two lactobacilli strains, delayed the growth of P. commune, M. racemosus and R. mucilaginosa for 2–24 days on Sour Cream, depending of the antifungal culture inoculum, and the growth of P. commune in semi-hard cheese for 1–6 days. Antifungal cultures had no effect on organoleptic properties at low inoculum level (6 logCFU/mL) [2]. Overall, 53 antifungal compounds were detected, of which 33 were in significantly higher amount in at least one product inoculated with an antifungal culture compared to the controls. They were present at concentrations below their minimum inhibitory concentration and thus could act in synergy. Among them, the most commonly identified were acetic, hydroxyphenyllactic, phenyllactic, 3-phenylpropanoic, 3-(4-hydroxyphenyl)propanoic and 5-oxopyrrolidine-2-carboxylic acids, diacetyl, acetoin, and a yet unidentified volatile compound. Our screening approach allowed developing antifungal combinations that exhibit significant antifungal activity and providing future prospects for use as bioprotective cultures in dairy products. This extensive study also contributes to improve the knowledge about the action mode of antifungal lactobacilli.

  • Potential of lactic acid bacteria combinations as antifungal cultures in pilot scale dairy products.
    2019
    Co-Authors: Marcia Leyva Salas, Jerome Mounier, Anne Thierry, Manon Chatel, Gilles Garric, Florence Valence-bertel, Marielle Harel-oger, Mathilde Lemaître, Emmanuel Coton
    Abstract:

    Consumer's demand for naturally preserved food products is growing and the use of bioprotective cultures is an alternative to chemical preservatives or a complementary tool to hurdle technologies to avoid or delay fungal spoilage of dairy products. To develop antifungal cultures for the dairy product biopreservation, experiments were conducted both in vitro and in situ. Firstly, the antifungal activity of 32 strains of lactic acid bacteria (LAB) and propionibacteria was screened alone, and then on combinations based on 5 selected lactobacilli strains. This screening was performed in yogurt and cheese models against four major spoilage fungi previously isolated from contaminated dairy products (Penicillium commune, Mucor racemosus, Galactomyces geotrichum, and Yarrowia lipolytica). Selected combinations were then tested as adjunct cultures in Sour Cream and semi-hard cheeses produced at a pilot scale to evaluate their antifungal activity during challenge tests against selected fungal targets (P. commune, M. racemosus, and Rhodotorula mucilaginosa) and shelf life tests; and their impact on product organoleptic properties. The screening step allowed selecting two binary combinations, A1 and A3 composed of Lactobacillus plantarum L244 and either Lactobacillus harbinensis L172 or Lactobacillus rhamnosus CIRM-BIA1113, respectively. In situ assays showed that the A1 combination delayed the growth of P. commune, M. racemosus and R. mucilaginosa for 2-24 days on Sour Cream depending of the antifungal culture inoculum, without effect on organoleptic properties at low inoculum (106 colony-forming units (CFU)/mL). Moreover, the A1 and A3 combinations also delayed the growth of P. commune in semi-hard cheese for 1-6 days and 1 day, respectively. Antifungal cultures neither impacted the growth of starter cultures in both Sour Cream and cheese nor the products' pH, although post acidification was observed in Sour Cream supplemented with these combinations at the highest concentrations (2.107 CFU/mL). The combination of both in vitro and in situ screening assays allowed developing 2 antifungal combinations exhibiting significant antifungal activity and providing future prospects for use as bioprotective cultures in dairy products.

  • Selection of Algerian lactic acid bacteria for use as antifungal bioprotective cultures and application in dairy and bakery products
    Food Microbiology, 2019
    Co-Authors: Massinissa Ouiddir, Guessas Bettache, Marcia Leyva Salas, Samira Brahimi, Kihel Mabrouk, Audrey Pawtowski, Christelle Donot, Emmanuel Coton, Jerome Mounier
    Abstract:

    In the context of a demand for “preservative-free” food products, biopreservation appears as a promising alternative to either replace or reduce the use of chemical preservatives. The purpose of this study was to evaluate the antifungal activity of a collection of lactic acid bacteria (n=194), and then to evaluate the applicability and efficacy of selected ones used as bioprotective cultures against mold spoilers in dairy and bakery products. First, lactic acid bacteria were isolated from various Algerian raw milk samples and Amoredj, a traditional fermented product. Secondly, in vitro screening tests against Mucor racemosus UBOCC-A-109155, Penicillium commune UBOCC-A-116003, Yarrowia lipolytica UBOCC-A-216006, Aspergillus tubingensis AN, Aspergillus flavus T5 and Paecilomyces formosus AT allowed for the selection of 3 active strains, namely Lactobacillus plantarum CH1, Lactobacillus paracasei B20 and Leuconostoc mesenteroides L1. In situ tests were then performed to validate their activity in actual products (Sour Cream and Sourdough bread) challenged with fungal spoilers. These tests showed that antifungal LAB could slow the fungal target growth and could be candidates of interest for industrial applications. Finally, organic acids and various antifungal compounds produced in Sour Cream and Sourdough bread by the selected LAB, and thus potentially supporting the observed antifungal activity, were identified and quantified by HPLC and LC-QTOF.

  • Composés potentiellement support de l’activité antifongique de cultures bioprotectrices dans des produits laitiers
    2018
    Co-Authors: Marcia Leyva Salas, Jerome Mounier, Emmanuel Coton, Florence Valence-bertel, Marie-bernadette Maillard, Anne Thierry
    Abstract:

    Fungi are commonly responsible for dairy product spoilage, which leads to substantial economic losses for the dairy industry as well as consumer dissatisfaction. Lactic acid bacteria can play an active role in the bioprotection of fermented dairy product, by producing a large range of antifungal metabolites. In a previous study, 3 binary combinations of lactobacilli strains were selected from a screening of the antifungal activity of 32 strains tested as adjunct cultures in yogurt and cheese models and the applicability of 2 of them in dairy products was validated at the pilot scale in Sour Cream and semi-hard cheese. Thus, the aim of the present study was to investigate the compounds produced by these antifungal cultures in these dairy products with a potential role in the observed antifungal activity. Using four different analytical methods including high performance liquid chromatography and gas chromatography combined or not with mass spectrometry, 53 compounds with known antifungal activity were detected in at least one of the four dairy products analyzed. Each antifungal culture produced a cocktail of 2 to 27 compounds, depending on the product. Acetic acid, diacetyl, hydroxyphenyllactic acid, pyruvic acid, phenyllactic acid, succinic acid, decanoic acid and some long-chain unsaturated fatty acids were the most commonly identified compounds. Their concentrations markedly differed according to the considered dairy product. Lactic, acetic, and citric acids were the most abundant compounds, while most of the other compounds were present in concentrations