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Georges Daube - One of the best experts on this subject based on the ideXlab platform.

  • Modeling the Growth and Interaction Between Brochothrix thermosphacta, Pseudomonas spp., and Leuconostoc gelidum in Minced Pork Samples.
    Frontiers in microbiology, 2020
    Co-Authors: Emilie Cauchie, Papa-abdoulaye Fall, Laurent Delhalle, Ghislain Baré, Assia Tahiri, Bernard Taminiau, N. Korsak, Sophie Burteau, Frédéric Farnir, Georges Daube
    Abstract:

    The aim of this study was to obtain the growth parameters of specific spoilage micro-organisms previously isolated in Minced Pork (MP) samples and to develop a three-spoilage species interaction model under different storage conditions. Naturally contaminated samples were used to validate this approach by considering the effect of the food microbiota. Three groups of bacteria were inoculated on irradiated samples, in mono- and in co-culture experiments (n = 1152): Brochothrix thermosphacta, Leuconostoc gelidum, and Pseudomonas spp. (Pseudomonas fluorescens and Pseudomonas fragi). Samples were stored in two food packaging [food wrap and modified atmosphere packaging (CO2 30%/O2 70%)] at three isothermal conditions (4, 8, and 12°C). Analysis was carried out by using both 16S rRNA gene amplicon sequencing and classical microbiology in order to estimate bacterial counts during the storage period. Growth parameters were obtained by fitting primary (Baranyi) and secondary (square root) models. The food packaging shows the highest impact on bacterial growth rates, which in turn have the strongest influence on the shelf life of food products. Based on these results, a three-spoilage species interaction model was developed by using the modified Jameson-effect model and the Lotka Volterra (prey-predator) model. The modified Jameson-effect model showed slightly better performances, with 40-86% out of the observed counts falling into the Acceptable Simulation Zone (ASZ). It only concerns 14-48% for the prey-predator approach. These results can be explained by the fact that the dynamics of experimental and validation datasets seems to follow a Jameson behavior. On the other hand, the Lotka Volterra model is based on complex interaction factors, which are included in highly variable intervals. More datasets are probably needed to obtained reliable factors, and so better model fittings, especially for three- or more-spoilage species interaction models. Further studies are also needed to better understand the interaction of spoilage bacteria between them and in the presence of natural microbiota.

  • assessment of spoilage bacterial communities in food wrap and modified atmospheres packed Minced Pork meat samples by 16s rdna metagenetic analysis
    Frontiers in Microbiology, 2020
    Co-Authors: Emilie Cauchie, Papa-abdoulaye Fall, Laurent Delhalle, Ghislain Baré, Assia Tahiri, Bernard Taminiau, N. Korsak, Sophie Burteau, Frédéric Farnir, Georges Daube
    Abstract:

    Although several studies have focused on the dynamics of bacterial food community, little is known about the variability of batch production and microbial changes that occur during storage. The aim of the study was to characterize the microbial spoilage community of Minced Pork meat samples, among different food production and storage, using both 16S rRNA gene sequencing and classical microbiology. Three batches of samples were obtained from four local Belgian facilities (A, B, C, D) and stored until shelf life under food wrap (FW) and modified atmosphere packaging (MAP, CO2 30%/O2 70%), at constant and dynamic temperature. Analysis of 288 samples were performed by 16S rRNA gene sequencing in combination with counts of psychrotrophic and lactic acid bacteria at 22°C. At the first day of storage, different psychrotrophic counts were observed between the four food companies (Kruskal-Wallist test, p-value 5% in relative abundance) were identified in MAP and 7 in FW. Pseudomonas was more present in FW and this genus was potentially replaced by Brochothrix in MAP (two-sided Welch’s t-test, p-value<0.05). Also, a high Bray-Curtis dissimilarity in genus relative abundance was observed between food companies and batches. Although the bacteria consistently dominated the microbiota in our samples are known, results indicated that bacterial diversity needs to be addressed on the level of food companies, batches variation and food storage conditions. Present data illustrate that the combined approach provides complementary results on microbial dynamics in Minced Pork meat samples, considering batches and packaging variations.

  • assessing interventions by quantitative risk assessment tools to reduce the risk of human salmonellosis from fresh Minced Pork meat in belgium
    Journal of Food Protection, 2009
    Co-Authors: Laurent Delhalle, N. Korsak, Frédéric Farnir, Claude Saegerman, Winy Messens, Y Van Der Stede, Georges Daube
    Abstract:

    The risk of human salmonellosis through the consumption of Minced Pork meat in Belgium was assessed via a modular risk model covering Pork meat production from lairage to human consumption. The main goal of the model was to give concrete options to reduce effectively the risk of human salmonellosis through the consumption of Minced Pork meat. These options (scenarios) were elaborated with reference to the international situation and the literature to give concrete and realistic possibilities for improving the microbiological quality of Pork meat and to reduce the number of human salmonellosis cases per year in Belgium. The model estimates 15,376 cases of human salmonellosis per year in Belgium due to the consumption of Minced Pork meat. The results of the scenarios showed that the risk of human salmonellosis could be significantly reduced by efforts all along the Pork meat production chain but also by efforts made by consumers. The responsibility of food business operators for the Pork meat production chain is high in relation to the microbiological quality of meat delivery, especially at the slaughterhouse. Consumers also need to be aware of good hygiene practices during preparation of the meat at home. Cross-contamination with raw food can be avoided by changing the habits and the behavior of the household cook. The results of these scenarios would be useful for the food business operators involved in the Pork meat chain and for public health authorities.

Jingrong Cheng - One of the best experts on this subject based on the ideXlab platform.

  • effects of mulberry polyphenols on oxidation stability of sarcoplasmic and myofibrillar proteins in dried Minced Pork slices during processing and storage
    Meat Science, 2020
    Co-Authors: Jingrong Cheng, Xueming Liu, Rong Xiang, Mingjun Zhu
    Abstract:

    Abstract This experiment was designed to evaluate the influence of mulberry polyphenols (MP) on oxidation stability of sarcoplasmic and myofibrillar proteins in dried Minced Pork slice during processing and storage. Composition, amino acid side chain modification, average particle size, hydrophobicity and solubility of proteins in the slices were investigated. MP displayed protective effects on oxidation stability of sarcoplasmic and myofibrillar proteins in slices, considering carbonyl formation and transformation from SH group to S S group were remarkably retarded by MP. Proteins in MP-treated slices possessed larger average particle size but lower aggregation during processing and storage. Meanwhile, the strengthened ionic bonds and weakened hydrogen, hydrophobic and disulfide bond could be responsible for the improved protein stability of slice with MP. All these results suggested that mulberry polyphenol could improve protein oxidation stability in meat products.

  • the effects of thermal processing and β cyclodextrin on extractable polyphenols in mulberry juice enriched dried Minced Pork slices
    Lwt - Food Science and Technology, 2019
    Co-Authors: Jingrong Cheng, Xueming Liu, Rong Xiang, Mingjun Zhu
    Abstract:

    Abstract To explore strategies for improving polyphenols retention in hot processed food, the effects of heat treatment time-temperature combinations and β-cyclodextrin addition on the extractable polyphenols in mulberry juice-enriched dried Minced Pork slices were studied. The results indicated that phenolic compounds underwent the greatest losses with processing conditions of drying at high temperature × short time followed by baking at low temperature × long time. A procedure of drying for 10 h at 40 °C followed by baking for 3 min at 150 °C was recommended for slice preparation on the basis of the highest retention rates of phenols (54.84% polyphenols, 39.1% flavonoids, and 59.62% anthocyanins). The total polyphenol content, total flavonoid content, total anthocyanin content, ABTS▪+ scavenging ability, ferric-reducing antioxidant power, and oxygen radical-absorbance capacity of the product could be further enhanced by adding 1% β-cyclodextrin. Four phenolic acids, three flavonoids, and two anthocyanins were detected in the products. Most phenols remained stable during storage except for cryptochlorogenic acid, caffeic acid and quercetin; β-cyclodextrin did not effectively prevent the degradation of the latter two. Overall, the results suggest that optimizing the heat treatment process as well as adding β-cyclodextrin may be promising strategies for improving the stability of mulberry polyphenols.

  • effect of microencapsulated process on stability of mulberry polyphenol and oxidation property of dried Minced Pork slices during heat processing and storage
    Lwt - Food Science and Technology, 2019
    Co-Authors: Jingrong Cheng, Xueming Liu, Mingjun Zhu
    Abstract:

    Abstract Microencapsulation is a promising technique for improving the stability of bioactive compounds. This study is to evaluate the effect of mulberry polyphenols microcapsules (MPM) as a partial substitute of mulberry polyphenol (MP) in mitigating of polyphenols degradation and oxidation of dried Minced Pork slice. Results presented that stability of MP is remarkable enhanced when it was microencapsulated using gum Arabic and the optimum core/wall ratio was 1/90. Partial replacement of MP by MPM as antioxidant in slices can effectively enhance polyphenols stability while exhibit synergistic inhibitory effect on protein and lipid oxidation. After 20 days storage, about 50.63% phenolic, 37.95% flavonoid and 51.32% anthocyanin were recovered in slices made with both MPM and MP, and the slices showed the best oxidation stability among all tests and good color stability. All these results demonstrated that mulberry polyphenol may be substituted for chemical antioxidants for meat products by microencapsulation technology.

  • stability of phenolic compounds and antioxidant capacity of concentrated mulberry juice enriched dried Minced Pork slices during preparation and storage
    Food Control, 2018
    Co-Authors: Jingrong Cheng, Xueming Liu, Wei Zhang, Zhiyi Chen, Xuping Wang
    Abstract:

    Abstract Functional foods have been of increasing demand due to the growing consumer awareness of the relationship between diet and health. Addition of healthy ingredients to meat products is an important method for development of functional meat products. In this contribution, functional dried-Minced Pork slices incorporated with concentrated mulberry juice (CMJ) were developed and stability of phenolic compounds and antioxidant capacity during product preparation and storage were evaluated. The CMJ contained high amounts of total phenolics, anthocyanin and flavonoids (19.13 ± 0.64 mg GAE/g d.m., 4.91 ± 0.18 C3GE mg/g d.m. and 18.39 ± 1.21 mg CE/g d.m., respectively) and showed excellent antioxidant activities in all assays used. CMJ incorporation drastically minimized lipid and protein oxidation of dried-Minced Pork slices by decreasing thiobarbituric acid-reactive substances (TBARS) value and carbonyls content during processing and storage. Thermal treatment significantly destroyed the main antioxidant ingredients including anthocyanins, flavonoids, and phenolics in dried-Minced Pork slices with added CMJ; however, this deterioration could be effectively counteracted by using β-cyclodextrin. The redness increased but lightness decreased with CMJ added, and color of the product remained stable during storage. Therefore, CMJ rich in phenolic compounds could be used as a natural antioxidant and pigment in dried-Minced Pork slices with suitable protective strategy.

  • inhibitory effect of mulberry morus alba polyphenol on the lipid and protein oxidation of dried Minced Pork slices during heat processing and storage
    Lwt - Food Science and Technology, 2018
    Co-Authors: Mingjun Zhu, Xueming Liu, Jingrong Cheng
    Abstract:

    Abstract This study aims to assess the antioxidant efficacy of mulberry (Morus alba) polyphenol (MP) in vacuum-packed dried Minced Pork slices stored at room temperature for 20 days. Dried Minced Pork slices were manufactured with 20 g/kg, 40 g/kg MP or 0.2 g/kg BHT, respectively. The results presented that MP significantly reduced TBRAS values increment and carbonyls formation while decelerated sulfhydryl losses in dried Minced Pork slices. Dried Minced Pork slices manufactured with MP gained higher a* value (P

Cauchie Emilie - One of the best experts on this subject based on the ideXlab platform.

  • Assessment of spoilage bacterial communities in food wrap and modified atmospheres-packed Minced Pork meat samples by 16S rDNA metagenetic analysis.
    2020
    Co-Authors: Cauchie Emilie, Korsak Koulagenko Nicolas, Baré Ghislain, Tahiri Assia, Delhalle Laurent, Taminiau Bernard, Burteau Sophie, Fall, Abdoulaye Papa, Farnir Frédéric, Daube Georges
    Abstract:

    Although several studies have focused on the dynamics of bacterial food community, little is known about the variability of batch production and microbial changes that occur during storage. The aim of the study was to characterize the microbial spoilage community of Minced Pork meat samples, among different food production and storage, using both 16S rRNA gene sequencing and classical microbiology. Three batches of samples were obtained from four local Belgian facilities (A–D) and stored until shelf life under food wrap (FW) and modified atmosphere packaging (MAP, CO2 30%/O2 70%), at constant and dynamic temperature. Analysis of 288 samples were performed by 16S rRNA gene sequencing in combination with counts of psychrotrophic and lactic acid bacteria at 22◦C. At the first day of storage, different psychrotrophic counts were observed between the four food companies (Kruskal-Wallist test, p-value 5% in relative abundance) were identified in MAP and 7 in FW. Pseudomonas was more present in FW and this genus was potentially replaced by Brochothrix in MAP (two-sided Welch’s t-test, p-value < 0.05). Also, a high Bray-Curtis dissimilarity in genus relative abundance was observed between food companies and batches. Although the bacteria consistently dominated the microbiota in our samples are known, results indicated that bacterial diversity needs to be addressed on the level of food companies, batches variation and food storage conditions. Present data illustrate that the combined approach provides complementary results on microbial dynamics in Minced Pork meat samples, considering batches and packaging variations.Peer reviewe

  • Développement d’une approche de modélisation pour la caractérisation et la prévision de la dynamique des microbiotes bactériens altérants dans les denrées alimentaires périssables
    Université de Liège ​Liège ​​Belgique, 2020
    Co-Authors: Cauchie Emilie
    Abstract:

    Food waste is currently a major problem since it is estimated that about one third of the food produced in the world is discarded before it is consumed. The reasons for these food losses and waste are varied and one cause is the bacterial spoilage, rendering foods unacceptable for consumption. The study of the dynamics of bacterial spoilage populations and the prediction of their dynamics would therefore be interesting to better understand and anticipate this phenomenon. This research focused on the study of predictive models for spoilage bacteria of fresh meat and meat products, considered as highly perishable foodstuffs. The two working matrices were Pork Minced meat and white pudding, considering variations in storage conditions (temperature and packaging). The first chapter of this thesis provides a general overview of bacterial spoilage of meat and meat products, as well as factors that may promote or limit its development. The different techniques used in this study to characterize and modelize the dynamics of spoilage microbiota are also described. This research was then divided into four main areas that are discussed in the other chapters: (1) describing the spoilage bacterial microbiota naturally present in the matrices studied; (2) characterizing the spoilage bacteria of interest for these products; (3) developing and validating predictive models with one or more bacteria; (4) and studying the metabolome of Minced meat inoculated by spoilage microorganisms of interest. These studies have demonstrated the interest of combining results from classical microbiology and 16S rDNA-based metagenetic to monitor and predict the dynamics of spoilage microbiota. For the white pudding, the bacteria of interest were Brochothrix thermosphacta, Carnobacterium maltaromaticum, Lactobacillus spp. (Lb. fuchuensis, Lb. graminis, Lb. oligofermentans), Lactococcus lactis, Leuconostoc mesenteroides, Pseudomonas psychrophila, Pseudomonas sp., Psychrobacter spp. (Psy. okhotskensis, Psy. urativorans), Raoultella terrigena and Serratia sp. For Minced Pork samples they were B. thermosphacta, Lb. algidus, Lc. piscium, Leuconostoc spp. (Ln. inhae, Ln. gelidum), Photobacterium spp. (Ph. kishitanii, Ph. phosphoreum) and Pseudomonas spp. (Ps. fragi, Ps. fluorescens, Ps. psychrophila). The type of packaging and storage temperature have a significant effect on the different dynamics, as well as the food companies and the production batches analyzed. Some of these bacteria of interest were then inoculated on sterile and non-sterile matrices, stored at different temperatures and packaging. The growth parameters to each bacterium were collected: maximum growth rate, lag time, minimum and maximum bacterial populations, time to reach the stationary phase, time to reach the spoilage threshold, minimum growth temperature, etc. Packaging seems to have the greatest impact on the maximum growth rate, itself having the greatest influence on the microbiological shelf life of the foods studied. Based on these data, good adjustments were obtained for the growth simulations, but overestimations were often observed. The same observations could be made by comparing the simulations performed on the white pudding with those available from software (ComBase and Sym'Previus). For Minced Pork, the data obtained allowed the development of three species interaction models based on the Lotka-Volterra (prey-predator model) and the modified Jameson models. The simulations obtained were validated by monitoring the spoilage microbiota of naturally contaminated Pork Minced meat matrices. The modified Jameson model obtained the best adjustments, although the prey-predator approach seems to be an interesting interaction model for complex microbiota. However, these proposals for models with three or more spoilage bacteria need to be validated by more experimental repetitions. Finally, metabolomic analyses (1H-NMR), in collaboration with CIRM-CHU, were performed in order to monitor the metabolites produced by inoculated bacteria in sterile Minced Pork samples. The dynamics of the metabolome for sterile non-inoculated matrices was also monitored. The different metabolomic patterns and metabolites produced were highlighted according to the inoculated bacteria and the food packaging. Moreover, the storage temperature seems to have the lowest impact on the metabolome. Development of predictive models based on data obtained by multi-omics analyses, combined with classical microbiology, provide an interesting approach. Further research on the development of complex models integrating the dynamics of two or more spoilage bacteria, interacting with each other and with the natural microbiota of foodstuffs, will be also an important step for better understanding and anticipating the bacterial spoilage of perishable foodstuffs

  • Développement d’une approche de modélisation pour la caractérisation et la prévision de la dynamique des microbiotes bactériens altérants dans les denrées alimentaires périssables
    Université de Liège ​Liège ​​Belgique, 2020
    Co-Authors: Cauchie Emilie
    Abstract:

    audience: researcher, professional, student, popularization, otherFood waste is currently a major problem since it is estimated that about one third of the food produced in the world is discarded before it is consumed. The reasons for these food losses and waste are varied and one cause is the bacterial spoilage, rendering foods unacceptable for consumption. The study of the dynamics of bacterial spoilage populations and the prediction of their dynamics would therefore be interesting to better understand and anticipate this phenomenon. This research focused on the study of predictive models for spoilage bacteria of fresh meat and meat products, considered as highly perishable foodstuffs. The two working matrices were Pork Minced meat and white pudding, considering variations in storage conditions (temperature and packaging). The first chapter of this thesis provides a general overview of bacterial spoilage of meat and meat products, as well as factors that may promote or limit its development. The different techniques used in this study to characterize and modelize the dynamics of spoilage microbiota are also described. This research was then divided into four main areas that are discussed in the other chapters: (1) describing the spoilage bacterial microbiota naturally present in the matrices studied; (2) characterizing the spoilage bacteria of interest for these products; (3) developing and validating predictive models with one or more bacteria; (4) and studying the metabolome of Minced meat inoculated by spoilage microorganisms of interest. These studies have demonstrated the interest of combining results from classical microbiology and 16S rDNA-based metagenetic to monitor and predict the dynamics of spoilage microbiota. For the white pudding, the bacteria of interest were Brochothrix thermosphacta, Carnobacterium maltaromaticum, Lactobacillus spp. (Lb. fuchuensis, Lb. graminis, Lb. oligofermentans), Lactococcus lactis, Leuconostoc mesenteroides, Pseudomonas psychrophila, Pseudomonas sp., Psychrobacter spp. (Psy. okhotskensis, Psy. urativorans), Raoultella terrigena and Serratia sp. For Minced Pork samples they were B. thermosphacta, Lb. algidus, Lc. piscium, Leuconostoc spp. (Ln. inhae, Ln. gelidum), Photobacterium spp. (Ph. kishitanii, Ph. phosphoreum) and Pseudomonas spp. (Ps. fragi, Ps. fluorescens, Ps. psychrophila). The type of packaging and storage temperature have a significant effect on the different dynamics, as well as the food companies and the production batches analyzed. Some of these bacteria of interest were then inoculated on sterile and non-sterile matrices, stored at different temperatures and packaging. The growth parameters to each bacterium were collected: maximum growth rate, lag time, minimum and maximum bacterial populations, time to reach the stationary phase, time to reach the spoilage threshold, minimum growth temperature, etc. Packaging seems to have the greatest impact on the maximum growth rate, itself having the greatest influence on the microbiological shelf life of the foods studied. Based on these data, good adjustments were obtained for the growth simulations, but overestimations were often observed. The same observations could be made by comparing the simulations performed on the white pudding with those available from software (ComBase and Sym'Previus). For Minced Pork, the data obtained allowed the development of three species interaction models based on the Lotka-Volterra (prey-predator model) and the modified Jameson models. The simulations obtained were validated by monitoring the spoilage microbiota of naturally contaminated Pork Minced meat matrices. The modified Jameson model obtained the best adjustments, although the prey-predator approach seems to be an interesting interaction model for complex microbiota. However, these proposals for models with three or more spoilage bacteria need to be validated by more experimental repetitions. Finally, metabolomic analyses (1H-NMR), in collaboration with CIRM-CHU, were performed in order to monitor the metabolites produced by inoculated bacteria in sterile Minced Pork samples. The dynamics of the metabolome for sterile non-inoculated matrices was also monitored. The different metabolomic patterns and metabolites produced were highlighted according to the inoculated bacteria and the food packaging. Moreover, the storage temperature seems to have the lowest impact on the metabolome. Development of predictive models based on data obtained by multi-omics analyses, combined with classical microbiology, provide an interesting approach. Further research on the development of complex models integrating the dynamics of two or more spoilage bacteria, interacting with each other and with the natural microbiota of foodstuffs, will be also an important step for better understanding and anticipating the bacterial spoilage of perishable foodstuffs

  • A NMR-based metabolomics approach for reducing food losses: the example of Minced Pork meat
    2018
    Co-Authors: Cauchie Emilie, Korsak Koulagenko Nicolas, Leenders Justine, Baré Ghislain, Tahiri Assia, Delhalle Laurent, De Tullio Pascal, Daube Georges
    Abstract:

    In Europe, the losses of initial meat production represent 20% and more than half of this occurs at animal production, slaughtering, processing and distribution step. In order to control food waste, studies have highlighted the importance of monitoring the microbial diversity of food products because spoilage by bacteria that contaminate the food matrix is a major issue. As such, the combination of metabolomics data with other complementary approaches (classical microbiology and quality parameters) can gives the opportunity to gain deeper insights into and have a better comprehension of the spoilage mechanisms. The aim of the current study was to assess meat spoilage through the evolution of bacterial counts and changes in the metabolic profile of Minced Pork meat using Nuclear Magnetic Resonance (NMR) based metabolomics. Microbiological assessment, pH measurements, gas composition and metabolomics analysis were carried out in meat samples stored under food wrap and under modified atmosphere packaging (70% O2 – 30% CO2) at 4, 8 and 12°C during 13 days. All samples were irradiated and then inoculated separately with three dominant bacterial species: Brochothrix thermosphacta, Leuconostoc gelidum and Pseudomonas fragi. For all conditions, non-inoculated samples were also stored. Analysis were carried out at day 0 and at day 13 for metabolomics analysis, and each day for all others measurements. The multivariate analysis (PLS-DA) reveals a clear discrimination between: (i) the non-inoculated product at day 0 and at day 13, (ii) the inoculated and non-inoculated samples, (iii) the type of bacterium, and (iv) the packaging conditions. It can be observed that the type of bacterium inoculated had a higher impact on the metabolome than that the packaging conditions. Moreover, some metabolites are significantly increased: acetate and glycerol for B. thermosphacta, betaine and lactate for L. gelidum, threonine and glycine for P. fragi. Exploration of the correlations of NMR-based metabolomics results with others microbial parameters suggested their use as possible spoilage tool to provide information on Minced Pork meat spoilage and to follow intrinsically the evolution of the metabolomics pattern linked to a specific bacterium in a complex bacterial ecosystem.Peer reviewe

  • A NMR-based metabolomics approach for reducing food losses: the example of Minced Pork meat
    Asian Institute of Technology, 2018
    Co-Authors: Cauchie Emilie, Korsak Koulagenko Nicolas, Leenders Justine, Baré Ghislain, Tahiri Assia, Delhalle Laurent, De Tullio Pascal, Daube Georges
    Abstract:

    peer reviewedaudience: researcher, professionalIn Europe, the losses of initial meat production represent 20% and more than half of this occurs at animal production, slaughtering, processing and distribution step. In order to control food waste, studies have highlighted the importance of monitoring the microbial diversity of food products because spoilage by bacteria that contaminate the food matrix is a major issue. As such, the combination of metabolomics data with other complementary approaches (classical microbiology and quality parameters) can gives the opportunity to gain deeper insights into and have a better comprehension of the spoilage mechanisms. The aim of the current study was to assess meat spoilage through the evolution of bacterial counts and changes in the metabolic profile of Minced Pork meat using Nuclear Magnetic Resonance (NMR) based metabolomics. Microbiological assessment, pH measurements, gas composition and metabolomics analysis were carried out in meat samples stored under food wrap and under modified atmosphere packaging (70% O2 – 30% CO2) at 4, 8 and 12°C during 13 days. All samples were irradiated and then inoculated separately with three dominant bacterial species: Brochothrix thermosphacta, Leuconostoc gelidum and Pseudomonas fragi. For all conditions, non-inoculated samples were also stored. Analysis were carried out at day 0 and at day 13 for metabolomics analysis, and each day for all others measurements. The multivariate analysis (PLS-DA) reveals a clear discrimination between: (i) the non-inoculated product at day 0 and at day 13, (ii) the inoculated and non-inoculated samples, (iii) the type of bacterium, and (iv) the packaging conditions. It can be observed that the type of bacterium inoculated had a higher impact on the metabolome than that the packaging conditions. Moreover, some metabolites are significantly increased: acetate and glycerol for B. thermosphacta, betaine and lactate for L. gelidum, threonine and glycine for P. fragi. Exploration of the correlations of NMR-based metabolomics results with others microbial parameters suggested their use as possible spoilage tool to provide information on Minced Pork meat spoilage and to follow intrinsically the evolution of the metabolomics pattern linked to a specific bacterium in a complex bacterial ecosystem

George-john E. Nychas - One of the best experts on this subject based on the ideXlab platform.

  • rapid detection of Minced Pork and chicken adulteration in fresh stored and cooked ground meat
    Food Control, 2021
    Co-Authors: Lemoniachristina Fengou, Panagiotis Tsakanikas, George-john E. Nychas
    Abstract:

    Abstract A common fraudulent practice throughout the supply chain is the partial substitution of meat products with other meat species than the ones claimed. Thus, detection of meat adulteration using rapid, non-invasive methods during production, processing, distribution, consumption, and disposal of food products is of vital importance for the protection of consumers. In that framework the objective of this work was the detection of Minced Pork with chicken (and vice versa) adulteration in (a) raw fresh, (b) raw stored and (c) cooked Minced meat using multispectral imaging (MSI) in tandem with support vector machines classification (SVM). Multispectral images were acquired at 0 h (freshly ground meat samples, n = 360), after 24 h and 48 h (stored meat samples, n = 180). Subsequently, at 48 h of storage, samples were cooked, and new images were acquired (n = 180). SVM classification models were developed and externally validated with sets from (a), (b) and (c). Their performance for the external validation in terms of accuracy were: for (a) freshly ground meat, 96.67% (n = 360), (b) stored Minced meat, 0 h = 93.33%, 24 h = 97.78% and 48 h = 95.56%, (n = 180) and (c) cooked Minced meat, 95.56% (n = 180). MSI data coupled with SVM algorithm exhibit promising potential for the rapid detection of adulterated meat samples in all three cases.

  • estimation of Minced Pork microbiological spoilage through fourier transform infrared and visible spectroscopy and multispectral vision technology
    Foods, 2019
    Co-Authors: Lemoniachristina Fengou, Evgenia D Spyrelli, Alexandra Lianou, Panagiotis Tsakanikas, Efstathios Z Panagou, George-john E. Nychas
    Abstract:

    Spectroscopic and imaging methods coupled with multivariate data analysis have been increasingly studied for the assessment of food quality. The objective of this work was the estimation of microbiological quality of Minced Pork using non-invasive spectroscopy-based sensors. For this purpose, Minced Pork patties were stored aerobically at different isothermal (4, 8, and 12 °C) and dynamic temperature conditions, and at regular time intervals duplicate samples were subjected to (i) microbiological analyses, (ii) Fourier transform infrared (FTIR) and visible (VIS) spectroscopy measurements, and (iii) multispectral image (MSI) acquisition. Partial-least squares regression models were trained and externally validated using the microbiological/spectral data collected at the isothermal and dynamic temperature storage conditions, respectively. The root mean squared error (RMSE, log CFU/g) for the prediction of the test (external validation) dataset for the FTIR, MSI, and VIS models was 0.915, 1.173, and 1.034, respectively, while the corresponding values of the coefficient of determination (R2) were 0.834, 0.727, and 0.788. Overall, all three tested sensors exhibited a considerable potential for the prediction of the microbiological quality of Minced Pork.

  • genotypic characterization of brochothrix thermosphacta isolated during storage of Minced Pork under aerobic or modified atmosphere packaging conditions
    Meat Science, 2012
    Co-Authors: Olga S Papadopoulou, Agapi I Doulgeraki, Cristian Botta, Luca Simone Cocolin, George-john E. Nychas
    Abstract:

    Abstract A total of 306 colonies were isolated from the selective medium for Brochothrix spp., during the spoilage of Minced Pork stored at 0, 5, 10 and 15 °C and packed aerobically and under modified atmosphere packaging conditions (MAP). Brochothrix biodiversity was assessed by Pulsed Field Gel Electrophoresis (PFGE), and representative strains were further analysed by Rep-PCR using primer (GTG) 5 and Sau-PCR with primers SAG 1 and SAG 2 . Although, different results were obtained from the different methods, a significant diversity among isolates recovered from aerobic conditions was observed. On the contrary, isolates from MAP showed a lower degree of heterogeneity. The storage conditions affected the Brochothrix diversity, the strains isolated in the initial stage being different from the ones present at the final stage of storage at chill temperatures. A representative number of isolates, based on the results of the clustering by molecular methods, were subjected to 16S rRNA gene sequencing, revealing that all belonged to Brochothrix thermosphacta .

  • contribution of fourier transform infrared ftir spectroscopy data on the quantitative determination of Minced Pork meat spoilage
    Food Research International, 2011
    Co-Authors: Olga S Papadopoulou, Efstathios Z Panagou, Chrysoula C Tassou, George-john E. Nychas
    Abstract:

    Abstract The aim of this work was to investigate the feasibility of Fourier transform infrared (FTIR) spectroscopy to quantify biochemical changes occurring in fresh Minced Pork meat in the attempt to monitor spoilage. For this reason, partial least squares (PLS) models were constructed to correlate spectral data from FTIR with Minced Pork meat spoilage during aerobic storage of meat samples at different storage temperatures (0, 5, 10, and 15 °C). Spectral data were collected from the surface of meat samples in parallel with microbiological analysis to enumerate the population of total viable counts, Pseudomonas spp., Brochothrix thermosphacta , lactic acid bacteria and Enterobacteriaceae . Qualitative interpretation of spectral data was based on sensory evaluation, using a three point hedonic scale, discriminating meat samples in three quality classes, namely fresh, semi-fresh and spoiled. The purpose of the developed models was to classify Minced Pork samples in the respective quality class, and also to correlate the population dynamics of the microbial association with FTIR spectra. The obtained results demonstrated good performance in classifying meat samples in one of the three pre-defined sensory classes. The overall correct classification rate for the three sensory classes was 94.0% and 88.1% during model calibration and validation, respectively. Furthermore, PLS regression models were also employed to provide quantitative estimations of microbial counts during meat storage. The performance was based on graphical plots and statistical indices (bias factor, accuracy factor, standard error of calibration, standard error of prediction, and correlation coefficient). The values of the bias factor were close to unity for all microbial groups indicating no systematic bias of the models. Moreover, the calculated values of the accuracy factor showed that the average deviation between predictions and observations was 7.5% and 7.9% for total viable counts and Pseudomonas spp. and 10.7% and 11.3% for lactic acid bacteria and B. thermosphacta . Finally, correlations above 0.80 between observed and estimated counts were observed for both training and test data sets.

  • control of spoilage microorganisms in Minced Pork by a self developed modified atmosphere induced by the respiratory activity of meat microflora
    Food Microbiology, 2008
    Co-Authors: Konstantinos P Koutsoumanis, Eleftherios H Drosinos, Anastasios Stamatiou, George-john E. Nychas
    Abstract:

    The changes in microbial flora of Minced Pork during aerobic storage at 0, 5, 10 and 15 degrees C were studied. Minced Pork samples (100g) were packed using two types of packaging films: (a) a common food film with high permeability (HPF) and (b) a film with low permeability (LPF). The respiratory activity of meat microflora and the use of a LPF resulted in a modified atmosphere in the package headspace developed during storage. Oxygen concentration decreased from 18.7% (after packaging) to 7% (after 15 days of storage) in packages with LPF, stored at 0 degrees C, while CO(2) increased from 3% to 10.5%, respectively. On the contrary, no significant atmosphere changes were observed during storage of HPF packages. The self-developed modified atmosphere in LPF packages resulted in a significant inhibition of pseudomonad growth which was more pronounced at low storage temperatures. For example, during storage at 0 degrees C, the growth rate of pseudomonads in meat packed with LPF was reduced by 48.7% compared to HPF. At 10 degrees C the latter reduction decreased to 13.7%. LPF packaging was also found to inhibit the growth of Brochothrix thermosphacta but this inhibition was weaker compared to pseudomonads. The effect of storage temperature on the growth rate of pseudomonads and B. thermosphacta in Minced Pork packed with the different films was modeled using an Arrhenius equation. For both bacteria, the activation energy was higher for LPF packaging. This can be attributed to the increased inhibitory effect of the modified atmosphere at lower storage temperature. The Arrhenius model was further used to evaluate the effect of temperature on the time required by the two bacteria to reach a spoilage level of 10(7)CFU/g. The results showed that when LPF packaging is combined with effective temperature control the time-to-spoilage can be significantly extended compared to HPF packaging.

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  • Modeling the Growth and Interaction Between Brochothrix thermosphacta, Pseudomonas spp., and Leuconostoc gelidum in Minced Pork Samples.
    Frontiers in microbiology, 2020
    Co-Authors: Emilie Cauchie, Papa-abdoulaye Fall, Laurent Delhalle, Ghislain Baré, Assia Tahiri, Bernard Taminiau, N. Korsak, Sophie Burteau, Frédéric Farnir, Georges Daube
    Abstract:

    The aim of this study was to obtain the growth parameters of specific spoilage micro-organisms previously isolated in Minced Pork (MP) samples and to develop a three-spoilage species interaction model under different storage conditions. Naturally contaminated samples were used to validate this approach by considering the effect of the food microbiota. Three groups of bacteria were inoculated on irradiated samples, in mono- and in co-culture experiments (n = 1152): Brochothrix thermosphacta, Leuconostoc gelidum, and Pseudomonas spp. (Pseudomonas fluorescens and Pseudomonas fragi). Samples were stored in two food packaging [food wrap and modified atmosphere packaging (CO2 30%/O2 70%)] at three isothermal conditions (4, 8, and 12°C). Analysis was carried out by using both 16S rRNA gene amplicon sequencing and classical microbiology in order to estimate bacterial counts during the storage period. Growth parameters were obtained by fitting primary (Baranyi) and secondary (square root) models. The food packaging shows the highest impact on bacterial growth rates, which in turn have the strongest influence on the shelf life of food products. Based on these results, a three-spoilage species interaction model was developed by using the modified Jameson-effect model and the Lotka Volterra (prey-predator) model. The modified Jameson-effect model showed slightly better performances, with 40-86% out of the observed counts falling into the Acceptable Simulation Zone (ASZ). It only concerns 14-48% for the prey-predator approach. These results can be explained by the fact that the dynamics of experimental and validation datasets seems to follow a Jameson behavior. On the other hand, the Lotka Volterra model is based on complex interaction factors, which are included in highly variable intervals. More datasets are probably needed to obtained reliable factors, and so better model fittings, especially for three- or more-spoilage species interaction models. Further studies are also needed to better understand the interaction of spoilage bacteria between them and in the presence of natural microbiota.

  • assessment of spoilage bacterial communities in food wrap and modified atmospheres packed Minced Pork meat samples by 16s rdna metagenetic analysis
    Frontiers in Microbiology, 2020
    Co-Authors: Emilie Cauchie, Papa-abdoulaye Fall, Laurent Delhalle, Ghislain Baré, Assia Tahiri, Bernard Taminiau, N. Korsak, Sophie Burteau, Frédéric Farnir, Georges Daube
    Abstract:

    Although several studies have focused on the dynamics of bacterial food community, little is known about the variability of batch production and microbial changes that occur during storage. The aim of the study was to characterize the microbial spoilage community of Minced Pork meat samples, among different food production and storage, using both 16S rRNA gene sequencing and classical microbiology. Three batches of samples were obtained from four local Belgian facilities (A, B, C, D) and stored until shelf life under food wrap (FW) and modified atmosphere packaging (MAP, CO2 30%/O2 70%), at constant and dynamic temperature. Analysis of 288 samples were performed by 16S rRNA gene sequencing in combination with counts of psychrotrophic and lactic acid bacteria at 22°C. At the first day of storage, different psychrotrophic counts were observed between the four food companies (Kruskal-Wallist test, p-value 5% in relative abundance) were identified in MAP and 7 in FW. Pseudomonas was more present in FW and this genus was potentially replaced by Brochothrix in MAP (two-sided Welch’s t-test, p-value<0.05). Also, a high Bray-Curtis dissimilarity in genus relative abundance was observed between food companies and batches. Although the bacteria consistently dominated the microbiota in our samples are known, results indicated that bacterial diversity needs to be addressed on the level of food companies, batches variation and food storage conditions. Present data illustrate that the combined approach provides complementary results on microbial dynamics in Minced Pork meat samples, considering batches and packaging variations.

  • assessing interventions by quantitative risk assessment tools to reduce the risk of human salmonellosis from fresh Minced Pork meat in belgium
    Journal of Food Protection, 2009
    Co-Authors: Laurent Delhalle, N. Korsak, Frédéric Farnir, Claude Saegerman, Winy Messens, Y Van Der Stede, Georges Daube
    Abstract:

    The risk of human salmonellosis through the consumption of Minced Pork meat in Belgium was assessed via a modular risk model covering Pork meat production from lairage to human consumption. The main goal of the model was to give concrete options to reduce effectively the risk of human salmonellosis through the consumption of Minced Pork meat. These options (scenarios) were elaborated with reference to the international situation and the literature to give concrete and realistic possibilities for improving the microbiological quality of Pork meat and to reduce the number of human salmonellosis cases per year in Belgium. The model estimates 15,376 cases of human salmonellosis per year in Belgium due to the consumption of Minced Pork meat. The results of the scenarios showed that the risk of human salmonellosis could be significantly reduced by efforts all along the Pork meat production chain but also by efforts made by consumers. The responsibility of food business operators for the Pork meat production chain is high in relation to the microbiological quality of meat delivery, especially at the slaughterhouse. Consumers also need to be aware of good hygiene practices during preparation of the meat at home. Cross-contamination with raw food can be avoided by changing the habits and the behavior of the household cook. The results of these scenarios would be useful for the food business operators involved in the Pork meat chain and for public health authorities.

  • development of a quantitative microbial risk assessment for human salmonellosis through household consumption of fresh Minced Pork meat in belgium
    Risk Analysis, 2009
    Co-Authors: Kaatje Bollaerts, Laurent Delhalle, Winy Messens, Y Van Der Stede, Marc Aerts, Jeroen Dewulf, Dominiek Maes, Sophie Quoilin, Koen Mintiens, K Grijspeerdt
    Abstract:

    A quantitative microbial risk assessment (QMRA) according to the Codex Alimentarius Principles is conducted to evaluate the risk of human salmonellosis through household consumption of fresh Minced Pork meat in Belgium. The quantitative exposure assessment is carried out by building a modular risk model, called the METZOON-model, which covers the Pork production from farm to fork. In the METZOON-model, the food production pathway is split up in six consecutive modules: (1) primary production, (2) transport and lairage, (3) slaughterhouse, (4) postprocessing, (5) distribution and storage, and (6) preparation and consumption. All the modules are developed to resemble as closely as possible the Belgian situation, making use of the available national data. Several statistical refinements and improved modeling techniques are proposed. The model produces highly realistic results. The baseline predicted number of annual salmonellosis cases is 20,513 (SD 9061.45). The risk is estimated higher for the susceptible population (estimate 4.713 x 10(-5); SD 1.466 x 10(-5)) compared to the normal population (estimate 7.704 x 10(-6); SD 5.414 x 10(-6)) and is mainly due to undercooking and to a smaller extent to cross-contamination in the kitchen via cook's hands.