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G M Crovetto - One of the best experts on this subject based on the ideXlab platform.
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effect of ensiling alfalfa at low and high dry matter on production of milk used to make Grana Cheese
Journal of Dairy Science, 2001Co-Authors: G Colombari, G Borreani, G M CrovettoAbstract:The effect of alfalfa ensiled in bunker silos at high moisture [HM, 34% dry matter (DM)] and low moisture (LM, 56% DM) content on milk production and Grana Padano Cheese quality was studied. Forty Italian Friesian lactating cows were allotted to two groups and fed, in a crossover design experiment, two corn silage-based diets containing 27% of the total DM as HM or LM. Each of the two periods included 10 d of adaptation and 3 experimental weeks. Forage was cut in the mid-vegetative stage with, on average, 34% neutral detergent fiber and 19% crude protein (DM basis). The two alfalfa silages showed a different fermentation pattern with 4.04 and 1.25% of lactic acid, 1.95 and 0.42% of acetic acid, 9.1 and 4.8% of total N ammonia-N for HM and LM, respectively. No butyric acid was found. Clostridial spores and yeast showed no growth in both silages except in the first 2 wk of the experiment where slight aerobic deterioration occurred. The HM treatment resulted in slightly lower DM intake (19.3 vs. 19.9 kg/d) and milk protein content (3.33 vs. 3.38%), higher milk fat content (3.56 vs. 3.37%), and 4% fat-corrected milk (25.7 vs. 24.4 kg/d). Totally, 38 Cheeses obtained from over 19 tons of milk with an average yield efficiency of 6.8%, were produced. The milk renneting and microbiological properties and the Cheese quality were not significantly different between treatments. However, both treatments had on average 40% of low quality (butyric fermentation) Cheeses observed mainly in the first 2 wk of the experiment, when the number of clostridial spores found in alfalfa silages was significantly higher than in the subsequent weeks. The data obtained suggest that the microbial quality of milk depends more on careful management and monitoring all of the steps in milk production, from silage harvest through to Cheese making, than on the moisture level of alfalfa silage, provided that the latter is in a range of 35 to 55% DM.
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comparison of lucerne silage and ventilated hay in maize silage based rations for dairy cows for the production of milk destined for Grana Cheese
Grass and Forage Science, 1999Co-Authors: G Colombari, G Borreani, G M CrovettoAbstract:Three experiments were carried out to study the effects of feeding lucerne silage (wilted to give different drymatter (DM) contents) and ventilated hay to dairy cows on milk production, milk quality, milk-renneting properties, clostridial spore content and the quality of Cheese prepared from the milk. The lucerne, cut at vegetative or early-bud stages of maturity, was harvested from alternate windrows and conserved as silage or artificially dried hay. The lucerne was wilted until it reached different DM contents of 550, 360 and 432 g kg ‐1 in the three experiments, harvested, chopped with a selfloading forage wagon and ensiled in low and narrow clamps made up of transferable prefabricated walls. The organic acid content, pH, yeast and mould counts of the lucerne silage suggested that there was no aerobic deterioration. In each experiment, fifty Italian Friesian lactating cows were divided into two groups and fed two maize silage-based rations for 6 weeks, which only differed in the lucerne forage [silage (S) vs. ventilated hay (H)], in a cross-over experimental design. The lucerne in the rations represented 35%, 23% and 24% of the DM of the rations for the three experiments. The microbiological profiles of the ration were influenced more by the maize silage than by the lucerne silage. Individual daily DM intakes were similar for the two treatments in Experiments 1 and 3 (on average 18AE 7k g in Experiment 1 and 20AE3 kg in Experiment 3) and slightly lower for S cows in comparison to H cows in Experiment 2 (18AE0 vs. 19AE0 kg). Milk yields of S and H cows were 21AE0 and 20AE8, 20AE0 and 20AE 6( P <0 AE01), and 28AE4 and 27AE 9k g d ‐1 in Experiments 1, 2 and 3 respectively. Milk composition was similar for all the experiments for the two treatments, except that the protein content was lower and the fat content was higher in the silage treatment than in the hay. The renneting properties and microbiology of the milk were not influenced by the introduction of lucerne silage into the rations, although the season in which it was consumed had a greater effect on the microbiological content, in terms of standard bacterial counts, proteolytic, coli and lactic acid bacteria, and clostridia spores. The clostridial spore counts were always very low (< 400 per litre), thus fulfilling the requirements for top-quality milk for Grana Cheese production. In the third experiment, the quality of Grana Padano Cheese produced was examined, and no differences between treatments were observed after 12 months of maturation. These results show that lucerne silage can be included in the ration of dairy cows instead of ventilated lucerne hay, which is considered to be the top-quality hay available for the production of milk destined for Grana Cheese, without any negative effects on milk and Cheese quality.
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Comparison of lucerne silage and ventilated hay in maize silage‐based rations for dairy cows for the production of milk destined for Grana Cheese
Grass and Forage Science, 1999Co-Authors: G Colombari, G Borreani, G M CrovettoAbstract:Three experiments were carried out to study the effects of feeding lucerne silage (wilted to give different drymatter (DM) contents) and ventilated hay to dairy cows on milk production, milk quality, milk-renneting properties, clostridial spore content and the quality of Cheese prepared from the milk. The lucerne, cut at vegetative or early-bud stages of maturity, was harvested from alternate windrows and conserved as silage or artificially dried hay. The lucerne was wilted until it reached different DM contents of 550, 360 and 432 g kg ‐1 in the three experiments, harvested, chopped with a selfloading forage wagon and ensiled in low and narrow clamps made up of transferable prefabricated walls. The organic acid content, pH, yeast and mould counts of the lucerne silage suggested that there was no aerobic deterioration. In each experiment, fifty Italian Friesian lactating cows were divided into two groups and fed two maize silage-based rations for 6 weeks, which only differed in the lucerne forage [silage (S) vs. ventilated hay (H)], in a cross-over experimental design. The lucerne in the rations represented 35%, 23% and 24% of the DM of the rations for the three experiments. The microbiological profiles of the ration were influenced more by the maize silage than by the lucerne silage. Individual daily DM intakes were similar for the two treatments in Experiments 1 and 3 (on average 18AE 7k g in Experiment 1 and 20AE3 kg in Experiment 3) and slightly lower for S cows in comparison to H cows in Experiment 2 (18AE0 vs. 19AE0 kg). Milk yields of S and H cows were 21AE0 and 20AE8, 20AE0 and 20AE 6( P
G Colombari - One of the best experts on this subject based on the ideXlab platform.
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effect of ensiling alfalfa at low and high dry matter on production of milk used to make Grana Cheese
Journal of Dairy Science, 2001Co-Authors: G Colombari, G Borreani, G M CrovettoAbstract:The effect of alfalfa ensiled in bunker silos at high moisture [HM, 34% dry matter (DM)] and low moisture (LM, 56% DM) content on milk production and Grana Padano Cheese quality was studied. Forty Italian Friesian lactating cows were allotted to two groups and fed, in a crossover design experiment, two corn silage-based diets containing 27% of the total DM as HM or LM. Each of the two periods included 10 d of adaptation and 3 experimental weeks. Forage was cut in the mid-vegetative stage with, on average, 34% neutral detergent fiber and 19% crude protein (DM basis). The two alfalfa silages showed a different fermentation pattern with 4.04 and 1.25% of lactic acid, 1.95 and 0.42% of acetic acid, 9.1 and 4.8% of total N ammonia-N for HM and LM, respectively. No butyric acid was found. Clostridial spores and yeast showed no growth in both silages except in the first 2 wk of the experiment where slight aerobic deterioration occurred. The HM treatment resulted in slightly lower DM intake (19.3 vs. 19.9 kg/d) and milk protein content (3.33 vs. 3.38%), higher milk fat content (3.56 vs. 3.37%), and 4% fat-corrected milk (25.7 vs. 24.4 kg/d). Totally, 38 Cheeses obtained from over 19 tons of milk with an average yield efficiency of 6.8%, were produced. The milk renneting and microbiological properties and the Cheese quality were not significantly different between treatments. However, both treatments had on average 40% of low quality (butyric fermentation) Cheeses observed mainly in the first 2 wk of the experiment, when the number of clostridial spores found in alfalfa silages was significantly higher than in the subsequent weeks. The data obtained suggest that the microbial quality of milk depends more on careful management and monitoring all of the steps in milk production, from silage harvest through to Cheese making, than on the moisture level of alfalfa silage, provided that the latter is in a range of 35 to 55% DM.
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comparison of lucerne silage and ventilated hay in maize silage based rations for dairy cows for the production of milk destined for Grana Cheese
Grass and Forage Science, 1999Co-Authors: G Colombari, G Borreani, G M CrovettoAbstract:Three experiments were carried out to study the effects of feeding lucerne silage (wilted to give different drymatter (DM) contents) and ventilated hay to dairy cows on milk production, milk quality, milk-renneting properties, clostridial spore content and the quality of Cheese prepared from the milk. The lucerne, cut at vegetative or early-bud stages of maturity, was harvested from alternate windrows and conserved as silage or artificially dried hay. The lucerne was wilted until it reached different DM contents of 550, 360 and 432 g kg ‐1 in the three experiments, harvested, chopped with a selfloading forage wagon and ensiled in low and narrow clamps made up of transferable prefabricated walls. The organic acid content, pH, yeast and mould counts of the lucerne silage suggested that there was no aerobic deterioration. In each experiment, fifty Italian Friesian lactating cows were divided into two groups and fed two maize silage-based rations for 6 weeks, which only differed in the lucerne forage [silage (S) vs. ventilated hay (H)], in a cross-over experimental design. The lucerne in the rations represented 35%, 23% and 24% of the DM of the rations for the three experiments. The microbiological profiles of the ration were influenced more by the maize silage than by the lucerne silage. Individual daily DM intakes were similar for the two treatments in Experiments 1 and 3 (on average 18AE 7k g in Experiment 1 and 20AE3 kg in Experiment 3) and slightly lower for S cows in comparison to H cows in Experiment 2 (18AE0 vs. 19AE0 kg). Milk yields of S and H cows were 21AE0 and 20AE8, 20AE0 and 20AE 6( P <0 AE01), and 28AE4 and 27AE 9k g d ‐1 in Experiments 1, 2 and 3 respectively. Milk composition was similar for all the experiments for the two treatments, except that the protein content was lower and the fat content was higher in the silage treatment than in the hay. The renneting properties and microbiology of the milk were not influenced by the introduction of lucerne silage into the rations, although the season in which it was consumed had a greater effect on the microbiological content, in terms of standard bacterial counts, proteolytic, coli and lactic acid bacteria, and clostridia spores. The clostridial spore counts were always very low (< 400 per litre), thus fulfilling the requirements for top-quality milk for Grana Cheese production. In the third experiment, the quality of Grana Padano Cheese produced was examined, and no differences between treatments were observed after 12 months of maturation. These results show that lucerne silage can be included in the ration of dairy cows instead of ventilated lucerne hay, which is considered to be the top-quality hay available for the production of milk destined for Grana Cheese, without any negative effects on milk and Cheese quality.
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Comparison of lucerne silage and ventilated hay in maize silage‐based rations for dairy cows for the production of milk destined for Grana Cheese
Grass and Forage Science, 1999Co-Authors: G Colombari, G Borreani, G M CrovettoAbstract:Three experiments were carried out to study the effects of feeding lucerne silage (wilted to give different drymatter (DM) contents) and ventilated hay to dairy cows on milk production, milk quality, milk-renneting properties, clostridial spore content and the quality of Cheese prepared from the milk. The lucerne, cut at vegetative or early-bud stages of maturity, was harvested from alternate windrows and conserved as silage or artificially dried hay. The lucerne was wilted until it reached different DM contents of 550, 360 and 432 g kg ‐1 in the three experiments, harvested, chopped with a selfloading forage wagon and ensiled in low and narrow clamps made up of transferable prefabricated walls. The organic acid content, pH, yeast and mould counts of the lucerne silage suggested that there was no aerobic deterioration. In each experiment, fifty Italian Friesian lactating cows were divided into two groups and fed two maize silage-based rations for 6 weeks, which only differed in the lucerne forage [silage (S) vs. ventilated hay (H)], in a cross-over experimental design. The lucerne in the rations represented 35%, 23% and 24% of the DM of the rations for the three experiments. The microbiological profiles of the ration were influenced more by the maize silage than by the lucerne silage. Individual daily DM intakes were similar for the two treatments in Experiments 1 and 3 (on average 18AE 7k g in Experiment 1 and 20AE3 kg in Experiment 3) and slightly lower for S cows in comparison to H cows in Experiment 2 (18AE0 vs. 19AE0 kg). Milk yields of S and H cows were 21AE0 and 20AE8, 20AE0 and 20AE 6( P
Elena Franciosi - One of the best experts on this subject based on the ideXlab platform.
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the spatial distribution of bacteria in Grana Cheese during ripening
Systematic and Applied Microbiology, 2012Co-Authors: L. Monfredini, Agostino Cavazza, E. Poznanski, Luca Settanni, Elena FranciosiAbstract:Abstract The microbial composition and its spatial distribution of Grana Trentino, a hard Parmesan-like Cheese, was determined, from vat milk to Cheese. After cutting along the vertical axis of the Cheese wheels, three layers were sampled diagonally across the Cheese: under the Cheese rind, an intermediate section and the Cheese core. After two different ripening periods (9 and 18 months), the Cheese samples were analysed using traditional culture dependent and culture independent methods. Milk samples were dominated by mesophilic and psychrophilic bacterial counts. Thermophilic bacteria ( Lactobacillus helveticus ) were found in high amounts in cooked whey and natural whey starter cultures. After 9 months of ripening, lactic acid bacteria (LAB) counts were higher than those after 18 months. Furthermore, the LAB numbers in the Cheese core was lower than those under the rind or in the intermediate section. The main LAB species isolated from milk ( Lactococcus lactis , Pediococcus pentosaceus , Streptococcus uberis and Lactococcus garvieae ) were not found in the corresponding Cheeses. Some differences were observed in the species composition among the three Cheese sections. Microbiota under the rind and in the intermediate section was similar and dominated by Lactobacillus paracasei and Lactobacillus rhamnosus . The core, after 18 months of ripening, was characterized by a total absence of LAB. In each sample, all LAB were genotypically grouped and the different biotypes were subjected to several technological tests indicating that some non-starter LAB (NSLAB) displayed technological features that are favorable for the production of Grana Trentino Cheese.
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The spatial distribution of bacteria in Grana-Cheese during ripening
Systematic and Applied Microbiology, 2012Co-Authors: L. Monfredini, Agostino Cavazza, E. Poznanski, Luca Settanni, Elena FranciosiAbstract:The microbial composition and its spatial distribution of Grana Trentino, a hard Parmesan-like Cheese, was determined, from vat milk to Cheese. After cutting along the vertical axis of the Cheese wheels, three layers were sampled diagonally across the Cheese: under the Cheese rind, an intermediate section and the Cheese core. After two different ripening periods (9 and 18 months), the Cheese samples were analysed using traditional culture dependent and culture independent methods. Milk samples were dominated by mesophilic and psychrophilic bacterial counts. Thermophilic bacteria (Lactobacillus helveticus) were found in high amounts in cooked whey and natural whey starter cultures. After 9 months of ripening, lactic acid bacteria (LAB) counts were higher than those after 18 months. Furthermore, the LAB numbers in the Cheese core was lower than those under the rind or in the intermediate section. The main LAB species isolated from milk (Lactococcus lactis, Pediococcus pentosaceus, Streptococcus uberis and Lactococcus garvieae) were not found in the corresponding Cheeses. Some differences were observed in the species composition among the three Cheese sections. Microbiota under the rind and in the intermediate section was similar and dominated by Lactobacillus paracasei and Lactobacillus rhamnosus. The core, after 18 months of ripening, was characterized by a total absence of LAB. In each sample, all LAB were genotypically grouped and the different biotypes were subjected to several technological tests indicating that some non-starter LAB (NSLAB) displayed technological features that are favorable for the production of Grana Trentino Cheese. © 2011 Elsevier GmbH.
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Microbial analysis of raw cows’ milk used for Cheese-making: influence of storage treatments on microbial composition and other technological traits
World Journal of Microbiology and Biotechnology, 2011Co-Authors: Elena Franciosi, Agostino Cavazza, Luca Settanni, Nicola Cologna, E. PoznanskiAbstract:Raw milk used to produce Grana Cheese was subjected to several treatment regimes, including varying temperatures and storage times. Milk from morning and evening milking were transferred to a dairy factory separately (double delivery) or together (single delivery), after storage at the farm for 12 h; in the former case, milk was stored at 12 or 8°C, whereas, in the latter, it was kept at ambient temperature or 18°C. Values of pH of the vat milk were lower for milk samples kept at room temperature, while other physico-chemical parameters and rheological characteristics tested did not show significant differences linked to the different storage temperatures of milk used for “Grana Trentino” Cheese production. Total microorganisms and several microbial groups (psychrotrophic bacteria, coliforms, mesophilic and termophilic lactic acid bacteria, including enterococci, pseudomonads and clostridia) were detected and quantified by classical (plate count and most probable number) techniques, after each technological treatment for a total of 212 milk and cream samples. The application of a culture-independent microbiological strategy, consisting of denaturing gradient gel electrophoresis, allowed the recognition of several bacterial genera and species.
Erasmo Neviani - One of the best experts on this subject based on the ideXlab platform.
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influence of the temperature gradient on the growth of thermophilic lactobacilli used as natural starters in Grana Cheese
Journal of Dairy Science, 1998Co-Authors: Giorgio Giraffa, Lia Rossetti, G Mucchetti, Francesco Addeo, Erasmo NevianiAbstract:This study investigated the evolution of the Lactobacillus species and the microbial composition of the starter during Grana Cheese making. The early stages of Cheese making were studied, and both the composition of the natural whey starter and its modification in response to curd cooking were considered. The growth and distribution of the thermophilic lactobacilli in the Cheese at 48 h after molding was affected by the temperature gradient between the external and internal Cheese zones. Growth was maximum between 0 and 6 h in the Cheese exterior and between 6 and 24 h in the core. This variation occurred because the Cheese interior was around 52°C 6 h after molding, which is far from the optimum for the thermophilic lactobacilli growth. Dot-blot hybridization experiments allowed the identification of up to 280 isolates. Lactobacillus helveticus predominated in the natural whey starter and in the external Cheese zones. Distribution of Lactobacillus delbrueckii and the heterofermentative lactobacilli, which slowly increased from the molding until 48 h, was more variable in the internal regions than in the external regions of the Cheese. This study demonstrates that the thermophilic lactobacilli behave differently during the technological process than during experiments using laboratory models.
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evolution of lactic acid microflora during Grana Cheese making and ripening
M.A.N. Microbiologie aliments nutrition, 1997Co-Authors: Giorgio Giraffa, G Mucchetti, Francesco Addeo, Erasmo NevianiAbstract:In Grana Padano or Parmigiano-Reggiano Cheese, the most widespread Italian Cheese varieties, the lactic acid microflora, deriving of both raw milk and Cheese whey starter, plays an important role in determining the typicality of the products. The thermophilic lactic acid bacteria (LAB), mostly derived from the whey starter, represent the predominant microflora during Cheese-making and the early stages of ripening. As the whey starter represents a mixed-strain culture responsible for complex biochemical phenomena, its role in curd acidification and Cheese ripening has been attentively considered. The various mesophiic LAB species enabling milk transformation and contributing together with the starter to the acidifying activity, prevent the spoilage bacteria development. Some of the non-starter LAB (NSLAB) of raw milk, such as Lactobacillus casei and pediococci, become the dominant microflora during ripening and are considered as important microflora for the development of the Cheese flavour. The present overview focus the attention on the main recent advances on the key role of thermophilic LAB in the two varieties of Cheese. Particular attention is paid on lactobacilli of the whey starter culture.
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acidification activity of thermophilic lactobacilli under the temperature gradient of Grana Cheese making
Journal of Dairy Science, 1995Co-Authors: Erasmo Neviani, Rosella Divizia, Emanuela Abbiati, Monica GattiAbstract:We have studied the growth and acidification activities of strains of the most important species present in natural whey starters for Grana Cheese under a temperature gradient that was similar to that used in the first 24 h of Cheese making. Results showed that strains can be classified according to their ability to adapt to Cheese-making conditions. Some strains that had good acidification activity at optimal temperature were not able to decrease pH under technological conditions of Cheese manufacture.
Paola Battilani - One of the best experts on this subject based on the ideXlab platform.
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modelling fungal growth mycotoxin production and release in Grana Cheese
Microorganisms, 2020Co-Authors: Marco Camardo Leggieri, Amedeo Pietri, Paola BattilaniAbstract:No information is available in the literature about the influence of temperature (T) on Penicillium and Aspergillus spp. growth and mycotoxin production on Cheese rinds. The aim of this work was to: (i) study fungal ecology on Cheese in terms of T requirements, focusing on the partitioning of mycotoxins between the rind and mycelium; and (ii) validate predictive models previously developed by in vitro trials. Grana Cheese rind blocks were inoculated with A. versicolor, P. crustosum, P. nordicum, P. roqueforti, and P. verrucosum, incubated at different T regimes (10–30 °C, step 5 °C) and after 14 days the production of mycotoxins (ochratoxin A (OTA); sterigmatocystin (STC); roquefortine C (ROQ-C), mycophenolic acid (MPA), Pr toxin (PR-Tox), citrinin (CIT), cyclopiazonic acid (CPA)) was quantified. All the fungi grew optimally around 15–25 °C and produced the expected mycotoxins (except MPA, Pr-Tox, and CIT). The majority of the mycotoxins produced remained in the mycelium (~90%) in three out of five fungal species (P. crustosum, P. nordicum, and P. roqueforti); the opposite occurred for A. versicolor and P. verrucosum with 71% and 58% of STC and OTA detected in Cheese rind, respectively. Available predictive models fitted fungal growth on the Cheese rind well, but validation was not possible for mycotoxins because they were produced in a very narrow T range.
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polyphasic identification of penicillia and aspergilli isolated from italian Grana Cheese
Food Microbiology, 2018Co-Authors: Simone Decontardi, Nelson Lima, Celia Maria Goncalves Soares, Paola BattilaniAbstract:Abstract Penicillium and Aspergillus genera, both including mycotoxin producing species, were reported as associated to Cheese and Cheese working environment, but never studied in an extensive way in Italian Grana Cheese (Grana Padano and Parmigiano Reggiano). The aim of this work was to address the identification of Aspergilli and Penicillia associated to Grana Cheese in order to lay down the basis for risk assessment and safe processing for a high quality production. One hundred and four strains belonging to Aspergillus and Penicillium genera were obtained from Cheese crust and from ripening room air (with the latter largely dominant), and identified following a polyphasic approach, strongly required for the identification at the species level. Morphological observation was used along with molecular techniques, RAPD-PCR fingerprinting and calmodulin gene sequencing (CaM), the former aimed to limit as much as possible the latter sequencing effort. Seventy four percent of the strains were assigned to Penicillium subgenus Penicillium, section Fasciculata. Main mycotoxin producing species identified were A. flavus, P. crustosum and P. verrucosum, while the dominant species in both air and Cheese crust was P. solitum, which has never been so far reported as mycotoxigenic. Results obtained in this study confirmed that mycotoxin contamination is a possible issue to face during Grana Cheese making.
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Modelling the sporulation of some fungi associated with Cheese, at different temperature and water activity regimes
International Journal of Food Microbiology, 2018Co-Authors: Marco Camardo Leggieri, Simone Decontardi, Paola BattilaniAbstract:Abstract The objectives of this study were to determine, in-vitro, the influence of temperature (T; 10–30 °C, step 5°), water activity (aw, 0.83–0.99; step 0.04) and time on sporulation (SPO) of some Cheese-related fungi belonging to Penicillium spp. and A. versicolor. Overall, sporulation started rapidly (8 h in optimal conditions); it was significantly influenced by T and aw and the fungi studied were clearly distinguished based on their thermo-hydro adaptation. Boundary conditions for sporulation were defined for all the fungi considered and the sporulation rate was successfully modelled, especially based on T and time regimes. Penicillium crustosum, P. nordicum and P. verrucosum showed optimum for SPO at T between 20 and 25 °C and their sporulation continued up to aw = 0.87 (aw = 0.83 for P. nordicum). They resulted the fungi best adapted to the environmental conditions of ripening Grana Cheese storehouses; therefore, it is expected they dominate on the Grana Cheese surface. Studies on Cheese are necessary to validate these results obtained on artificial media and without fungi co-occurrence.
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survey of penicillia associated with italian Grana Cheese
International Journal of Food Microbiology, 2017Co-Authors: Simone Decontardi, Antonio Mauro, Nelson Lima, Paola BattilaniAbstract:Abstract The present work aimed to contribute information on the mycobiota associated with ripening Grana Cheese, with focus on the genus Penicillium as potential mycotoxin producers. Eighteen wheels of Grana Cheese, aged in different storehouses situated in Northern Italy, were sampled to isolate associated fungi. Penicillium spp. were commonly dominant; morphological observation and gene sequencing were applied to identify Penicillium at species level. P. crustosum and P. solitum were the dominant species. Citrinin and ochratoxin A mycotoxins were analysed and the latter was found in all Grana Cheese samples. These results confirmed that a polyphasic approach is mandatory for Penicillium identification at species level.
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Modeling growth and toxin production of toxigenic fungi signaled in Cheese under different temperature and water activity regimes
Toxins, 2016Co-Authors: Marco Camardo Leggieri, Simone Decontardi, Amedeo Pietri, Terenzio Bertuzzi, Paola BattilaniAbstract:The aim of this study was to investigate in vitro and model the effect of temperature (T) and water activity (aw) conditions on growth and toxin production by some toxigenic fungi signaled in Cheese. Aspergillus versicolor, Penicillium camemberti, P. citrinum, P. crustosum, P. nalgiovense, P. nordicum, P. roqueforti, P. verrucosum were considered they were grown under different T (0–40 °C) and aw (0.78–0.99) regimes. The highest relative growth occurred around 25 °C; all the fungi were very susceptible to aw and 0.99 was optimal for almost all species (except for A. versicolor, awopt = 0.96). The highest toxin production occurred between 15 and 25 °C and 0.96–0.99 aw. Therefore, during Grana Cheese ripening, managed between 15 and 22 °C, ochratoxin A (OTA), penitrem A (PA), roquefortine-C (ROQ-C) and mycophenolic acid (MPA) are apparently at the highest production risk. Bete and logistic function described fungal growth under different T and aw regimes well, respectively. Bete function described also STC, PA, ROQ-C and OTA production as well as function of T. These models would be very useful as starting point to develop a mechanistic model to predict fungal growth and toxin production during Cheese ripening and to help advising the most proper setting of environmental factors to minimize the contamination risk.
