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Fresh-cut produces are often consumed uncooked, thus proper sanitation is essential for preventing cross contamination. The reduction and subsequent growth of Salmonella enterica sv Thompson were studied in pre-cut iceberg lettuce washed with simulated wash water (SWW), sodium hypochlorite (SH, free chlorine 25 mg/L), and peroxyacetic acid (PAA, 80 mg/L) and stored for 9 days under modified atmosphere at 9, 13, and 18 °C. Differences in reduction between SH and PAA were non-existent. Overall, visual quality, dehydration, leaf edge and superficial browning and aroma during storage at 9 °C were similar among treatments, but negative effects increased with temperature. These results demonstrated that PAA can be used as an effective alternative to chlorine for the disinfection of Salmonella spp. in fresh-cut lettuce. The growth of Salmonella enterica sv Thompson was successfully described with the Baranyi and Roberts growth model in the studied storage temperature range, and after treatment with SWW, chlorine, and PAA. Subsequently, predictive secondary models were used to describe the relationship between growth rates and temperature based on the models' family described by Belehrádek. Interestingly, the exposure to disinfectants biased growth kinetics of Salmonella during storage. Below 12 °C, growth rates in lettuce treated with disinfectant (0.010-0.011 log CFU/h at 9 °C) were lower than those in lettuce washed with water (0.016 log CFU/h at 9 °C); whereas at higher temperatures, the effect was the opposite. Thus, in this case, the growth rate values registered at 18 °C for lettuce treated with disinfectant were 0.048-0.054 log CFU/h compared to a value of 0.038 log CFU/h for lettuce treated with only water. The data and models developed in this study will be crucial to describing the wash-related dynamics of Salmonella in a risk assessment framework applied to fresh-cut produce, providing more complete and accurate risk estimates.

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In this study cut, pineapple slices of 1 cm thick were packaged and stored at different temperatures and equilibrium modified atmosphere packages (EMAPs) to determine changes of color and firmness over time to represent physicochemical shelf life. From the experimental data, a variance analysis was performed to determine the effect of temperature and O2 level on the evolution of color (CIELAB coordinates) and firmness. It was observed that the evolution in L* , a* , and b* coordinates is independent on O2 concentration in the EMAP system. After that, suitable models were adjusted to represent the change of the quality properties as a function of temperature by using first-order models to represent color and a power model for firmness. Likewise, a modified normal distribution function was adjusted to represent the coefficient of firmness loss depending on the O2 level besides the temperature effect. The firmness model was used to obtain a suitable equation to predict shelf life of the pineapple slices for different EMAP systems. Finally, a validation experiment was performed at 8 °C obtaining a high capacity of prediction (R2 adj > 0.90) compared with the experimental data. The adjusted model can be used to configure a satisfactory EMAP system for the best preservation of minimally processed pineapple from the predicted evolution of color, firmness, and shelf life depending on temperature and O2 concentration. PRACTICAL APPLICATION: In this work, we built a mathematical model to simulate the shelf life of pineapple cut into slices based on changes in color and firmness and as a function of temperature and oxygen level. These properties are truly relevant because they are very clear evidence of the fruit deterioration, and for that reason, we chose them for the model. The model we developed can be applied in retail and supermarket systems to determine precisely how long the product on the shelf can last before being disposed of, reducing material losses.

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Abstract: The aim of this study was to investigate the effects of different packaging systems on the shelf life of refrigerated ground beef. The ground beef samples were packaged as follows: AA (100% ambient air), 90O2:10CO2 (90% O2 and 10% CO2), 80O2:20CO2 (80% O2 and 20% CO2), 70O2:30CO2 (70% O2 and 30% CO2), 60O2:40CO2 (60% O2 and 40% CO2), 50O2:50CO2 (50% O2 and 50% CO2), 100O2 (100% O2), and VP (vacuum packaging). All treatments were analyzed daily for O2 and CO2 levels, pH, filtration time, total volatile basic nitrogen (TVB-N), aerobic mesophilic heterotrophic bacteria (AMHB), and aerobic psychrotrophic heterotrophic bacteria (APHB) over 20 days at 2 °C. All MAP systems had a decrease of O2 and an increase of CO2 levels during storage period (p < 0.05). Overall, the MAP systems were similarly able to decrease the pH and retard the increase of TVB-N and filtration time over the storage period (p > 0.05). Moreover, the MAP systems increased the lag phase and/or the generation time of both AMHB and APHB, extending the shelf life by 3 (90O2:10CO2), 4 (70O2:30CO2 and 100O2), and 5 days (80O2:20CO2, 60O2:40CO2, 50O2:50CO2, and VP). All MAP systems were equally effective in retarding physicochemical degradation; however, 80O2:20CO2, 60O2:40CO2, 50O2:50CO2, and VP were the most effective in impairing bacterial growth and extending the shelf life of ground beef stored under refrigeration.

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The effect of different modified atmosphere packaging regimes on the behavior of Salmonella spp. on minced meat was studied. Minced meat was experimentally contaminated with a Salmonella spp. cocktail (S. Enteritidis, S. Typhimurium, S. Infantis and S. Arizonae), packaged under vacuum or modified atmosphere with initial headspaces containing 20%O2/50%CO2/30%N2 and 20%O2/30%CO2/50%N2) and stored at 3 ± 1 °C for 12 days. Samples were analyzed for Salmonella spp., viable and lactic acid bacteria count every third day. Salmonella spp. counts decreased during storage in all packaging types, with reductions of about 1.5 log CFU/g. A significant difference (p < 0.01) was noted between Salmonella spp. counts in meat packaged in vacuum and modified atmospheres, although there was no significant difference in Salmonella spp. count between meat packaged in 50%CO2, and meat packaged in 30%CO2. At the end of the study, there were significant differences (p < 0.01; p < 0.05) in total viable and lactic acid bacterial counts between meat packaged in vacuum and modified atmosphere, and the lowest counts were noted in meat packaged in modified atmosphere with 50%CO2.(AU)

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Abstract The effect of different modified atmosphere packaging regimes on the behavior of Salmonella spp. on minced meat was studied. Minced meat was experimentally contaminated with a Salmonella spp. cocktail (S. Enteritidis, S. Typhimurium, S. Infantis and S. Arizonae), packaged under vacuum or modified atmosphere with initial headspaces containing 20%O2/50%CO2/30%N2 and 20%O2/30%CO2/50%N2) and stored at 3 ± 1 °C for 12 days. Samples were analyzed for Salmonella spp., viable and lactic acid bacteria count every third day. Salmonella spp. counts decreased during storage in all packaging types, with reductions of about 1.5 log CFU/g. A significant difference (p < 0.01) was noted between Salmonella spp. counts in meat packaged in vacuum and modified atmospheres, although there was no significant difference in Salmonella spp. count between meat packaged in 50%CO2, and meat packaged in 30%CO2. At the end of the study, there were significant differences (p < 0.01; p < 0.05) in total viable and lactic acid bacterial counts between meat packaged in vacuum and modified atmosphere, and the lowest counts were noted in meat packaged in modified atmosphere with 50%CO2.

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The effect of different modified atmosphere packaging regimes on the behavior of Salmonella spp. on minced meat was studied. Minced meat was experimentally contaminated with a Salmonella spp. cocktail (S. Enteritidis, S. Typhimurium, S. Infantis and S. Arizonae), packaged under vacuum or modified atmosphere with initial headspaces containing 20%O2/50%CO2/30%N2 and 20%O2/30%CO2/50%N2) and stored at 3±1°C for 12 days. Samples were analyzed for Salmonella spp., viable and lactic acid bacteria count every third day. Salmonella spp. counts decreased during storage in all packaging types, with reductions of about 1.5logCFU/g. A significant difference (p<0.01) was noted between Salmonella spp. counts in meat packaged in vacuum and modified atmospheres, although there was no significant difference in Salmonella spp. count between meat packaged in 50%CO2, and meat packaged in 30%CO2. At the end of the study, there were significant differences (p<0.01; p<0.05) in total viable and lactic acid bacterial counts between meat packaged in vacuum and modified atmosphere, and the lowest counts were noted in meat packaged in modified atmosphere with 50%CO2.

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The effect of rosemary (Rosmarinus officinalis L.) essential oil (REO) and modified-atmosphere packaging (MAP) on the survival of certain pathogens (Salmonella Typhimurium and Listeria monocytogenes) in poultry fillets and on their meat quality during 7 days of refrigerated storage were investigated. Because REO at 0.05% and 0.1% had weak antibacterial activity and REO at 0.3%, 0.5% and 1.0% imparted unacceptable organoleptic properties, only REO at 0.2% was used to treat the poultry meat. The results showed that adding 0.2% REO to poultry fillets did not reduce the size of the population of S. Typhimurium and L. monocytogenes. However, REO treatment significantly decreased the L* (lightness) value and increased the a* (redness) value of stored fillets, and adding REO in combination with MAP reduced the level of lipid oxidation. In conclusion, in a suitable combination, REO can be applied to improve the quality of meat, but further studies should be conducted to determine the appropriate commercial level for different meat products.

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The effect of rosemary (Rosmarinus officinalis L.) essential oil (REO) and modified-atmosphere packaging (MAP) on the survival of certain pathogens (Salmonella Typhimurium and Listeria monocytogenes) in poultry fillets and on their meat quality during 7 days of refrigerated storage were investigated. Because REO at 0.05% and 0.1% had weak antibacterial activity and REO at 0.3%, 0.5% and 1.0% imparted unacceptable organoleptic properties, only REO at 0.2% was used to treat the poultry meat. The results showed that adding 0.2% REO to poultry fillets did not reduce the size of the population of S. Typhimurium and L. monocytogenes. However, REO treatment significantly decreased the L* (lightness) value and increased the a* (redness) value of stored fillets, and adding REO in combination with MAP reduced the level of lipid oxidation. In conclusion, in a suitable combination, REO can be applied to improve the quality of meat, but further studies should be conducted to determine the appropriate commercial level for different meat products.(AU)

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The effect of rosemary (Rosmarinus officinalis L.) essential oil (REO) and modified-atmosphere packaging (MAP) on the survival of certain pathogens (Salmonella Typhimurium and Listeria monocytogenes) in poultry fillets and on their meat quality during 7 days of refrigerated storage were investigated. Because REO at 0.05% and 0.1% had weak antibacterial activity and REO at 0.3%, 0.5% and 1.0% imparted unacceptable organoleptic properties, only REO at 0.2% was used to treat the poultry meat. The results showed that adding 0.2% REO to poultry fillets did not reduce the size of the population of S. Typhimurium and L. monocytogenes. However, REO treatment significantly decreased the L* (lightness) value and increased the a* (redness) value of stored fillets, and adding REO in combination with MAP reduced the level of lipid oxidation. In conclusion, in a suitable combination, REO can be applied to improve the quality of meat, but further studies should be conducted to determine the appropriate commercial level for different meat products.

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This study evaluated the influence of good manufacturing practices (GMP) on the shelf life of refrigerated fillets of Nile tilapia (Oreochromis niloticus) packed in modified atmosphere packaging (MAP) and irradiated. In a first series of experiments, 120 tilapia fillets kept under controlled sanitary conditions were purchased from a fish market managed by a cooperative. A second lot totaling 200 tilapia fillets was obtained under controlled storage conditions from a pilot plant. The combined effects of MAP (40% CO2 and 60% N2) and irradiation (1.5 kGy) were investigated by monitoring physical and chemical (total volatile bases and pH), bacteriological (aerobic heterotrophic mesophilic and psychrophilic bacteria) and sensory (acceptance test) changes in the samples. The quality of samples decreased with storage time regardless of the treatment, remaining higher in fillets produced in the pilot plant in comparison with the commercially produced fillets. The observed shelf life of nonirradiated commercially produced fillets was only 3 days, compared to 8 days for those produced in the pilot plant, probably due to GMP in the latter. It was concluded that, even with a combination of proven conservation methods for meats, the adoption of good manufacturing practices still remains essential before, during, and after the filleting process in order to ensure the effectiveness of the entire treatment.

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O objetivo deste trabalho foi caracterizar a influência da embalagem em atmosfera modificada (EAM) e do ácido lático (AL) navalidade comercial da linguiça frescal de frango. Para tanto, foram processadas duas massas de linguiça, sendo uma delasadicionado ácido lático (0,15%). As linguiças foram então embaladas nas seguintes atmosferas: 100%ar atmosférico, 100%N2, 100% CO2, 80% CO2/20% N2, 40% CO2/60% N2 e 20% CO2/80% N2, e armazenadas durante 16 dias a 4±2oC. Foramrealizadas, nos dias 0, 1, 9 e 16, análises bacteriológicas: contagem em placa de bactérias heterotróficas aeróbias mesófilas,bactérias heterotróficas aeróbias psicrotróficas, bactérias ácido-láticas, enterobactérias e Pseudomonas; e determinaçãodo pH. A EAM a 80/20 CO2/N2 mostrou-se como método mais eficaz, sob o ponto de vista microbiológico, em termos deconservação da linguiça frescal de frango, atingindo ao final do experimento valores de 6,0; 5,3 e 5,0 Log UFC/g (bactériasmesófilas, psicrotróficas e ácido-láticas, respectivamente). Em relação à adição do AL, tal tratamento foi eficaz sob o aspectode inibição microbiológica em quase todas as atmosferas, com exceção da 80/20 CO2/N2. Durante o experimento, não foiobservado crescimento de enterobactérias e Pseudomonas. Em relação ao pH, pôde-se observar que a adição de 0,15% deAL provocou uma queda do pH de 5,89 para ~5,50, suficiente para acarretar uma inibição significativa da taxa de multiplicaçãomicrobiana nas diferentes atmosferas, exceto na 80/20 CO2/N2. Pôde se concluir que a EAM com 80/20 CO2/N2, mostrou-secomo o método de conservação mais eficaz quanto ao aumento da vida útil da linguiça de frango e a adição de 0,15% de ALdemonstrou ser uma alternativa eficaz para conservação deste produto.(AU)

The present work has an objective to observe and to characterize, through microbiological analyses and pH determination, the influence of the Modified Atmosphere Packaging (MAP) and the lactic acid addictive in shelf life of fresh poultry sausage. Two sausage batches were made under laboratory control. One of them was added of lactic acid (0.15%). The samples were processed, and packaged in plastic bags (four sausages per bag). Finally, the bags were filled with different atmospheres: 100% air, 100% N2, 100% CO2, 80/20 CO2/N2, 40/60 CO2/N2 and 20/80 CO2/N2. Samples were stored in walk?in cold rooms at 4±2°C. Samples were taken at different days of storage (zero, 1, 9 and 16). Both added and not added with lactic acid samples were subjected to total viable aerobic counts (mesophylic and psycrophylic), lactic acid bacteria, Enterobacteriaceae, and Pseudomonas sp. in specific media plates. Also, it was determinate the pH of all the samples. The results were arranged in tables and graphs for the descriptive statistical analyses. The MAP 80/20 CO2/N2 was the more effective method to conserve fresh poultry sausages, reaching at the end of the experiment values of 6.0; 5,3 and 5.0 Log UFC/g (mesophylic, psycrophylic and acid-lactic bacteria, respectively), comparing to the conventional package (100% air) and 100% N2 that reached at the end of the experiment maximum values of 8.8 and 9.4 Log UFC/g, respectively. The addition of the acid lactic was effective about the aspect of microbiological inhibition, reaching inferior values in almost all the atmospheres comparing to the samples without addition of the acid, except to 80/20 CO2/N2, that the values of the microbial count in both treatments (with and without acid) they were very close. During the experiment, it was not observed the growth of Enterobacteriaceae and Pseudomonas. Analyzing the pH, it can be observed that the addition of 0.15% lactic acid caused a fall of the pH of 5.89 for ~5.50, enough to inhibit the microbial multiplication in the different atmospheres, except in 80/20 CO2/N2. After analyzed this results, it was concluded that MAP to 80/20% of CO2/N2 was the more effective method to increase the shelf life of the fresh poultry sausage, added or not added with lactic acid; the addition of 0.15% of lactic acid was an effective alternative for conservation of fresh poultry sausage chicken, wrapped or not in modified atmosphere(AU)

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O objetivo deste trabalho foi caracterizar a influência da embalagem em atmosfera modificada (EAM) e do ácido lático (AL) navalidade comercial da linguiça frescal de frango. Para tanto, foram processadas duas massas de linguiça, sendo uma delasadicionado ácido lático (0,15%). As linguiças foram então embaladas nas seguintes atmosferas: 100%ar atmosférico, 100%N2, 100% CO2, 80% CO2/20% N2, 40% CO2/60% N2 e 20% CO2/80% N2, e armazenadas durante 16 dias a 4±2oC. Foramrealizadas, nos dias 0, 1, 9 e 16, análises bacteriológicas: contagem em placa de bactérias heterotróficas aeróbias mesófilas,bactérias heterotróficas aeróbias psicrotróficas, bactérias ácido-láticas, enterobactérias e Pseudomonas; e determinaçãodo pH. A EAM a 80/20 CO2/N2 mostrou-se como método mais eficaz, sob o ponto de vista microbiológico, em termos deconservação da linguiça frescal de frango, atingindo ao final do experimento valores de 6,0; 5,3 e 5,0 Log UFC/g (bactériasmesófilas, psicrotróficas e ácido-láticas, respectivamente). Em relação à adição do AL, tal tratamento foi eficaz sob o aspectode inibição microbiológica em quase todas as atmosferas, com exceção da 80/20 CO2/N2. Durante o experimento, não foiobservado crescimento de enterobactérias e Pseudomonas. Em relação ao pH, pôde-se observar que a adição de 0,15% deAL provocou uma queda do pH de 5,89 para ~5,50, suficiente para acarretar uma inibição significativa da taxa de multiplicaçãomicrobiana nas diferentes atmosferas, exceto na 80/20 CO2/N2. Pôde se concluir que a EAM com 80/20 CO2/N2, mostrou-secomo o método de conservação mais eficaz quanto ao aumento da vida útil da linguiça de frango e a adição de 0,15% de ALdemonstrou ser uma alternativa eficaz para conservação deste produto.

The present work has an objective to observe and to characterize, through microbiological analyses and pH determination, the influence of the Modified Atmosphere Packaging (MAP) and the lactic acid addictive in shelf life of fresh poultry sausage. Two sausage batches were made under laboratory control. One of them was added of lactic acid (0.15%). The samples were processed, and packaged in plastic bags (four sausages per bag). Finally, the bags were filled with different atmospheres: 100% air, 100% N2, 100% CO2, 80/20 CO2/N2, 40/60 CO2/N2 and 20/80 CO2/N2. Samples were stored in walk?in cold rooms at 4±2°C. Samples were taken at different days of storage (zero, 1, 9 and 16). Both added and not added with lactic acid samples were subjected to total viable aerobic counts (mesophylic and psycrophylic), lactic acid bacteria, Enterobacteriaceae, and Pseudomonas sp. in specific media plates. Also, it was determinate the pH of all the samples. The results were arranged in tables and graphs for the descriptive statistical analyses. The MAP 80/20 CO2/N2 was the more effective method to conserve fresh poultry sausages, reaching at the end of the experiment values of 6.0; 5,3 and 5.0 Log UFC/g (mesophylic, psycrophylic and acid-lactic bacteria, respectively), comparing to the conventional package (100% air) and 100% N2 that reached at the end of the experiment maximum values of 8.8 and 9.4 Log UFC/g, respectively. The addition of the acid lactic was effective about the aspect of microbiological inhibition, reaching inferior values in almost all the atmospheres comparing to the samples without addition of the acid, except to 80/20 CO2/N2, that the values of the microbial count in both treatments (with and without acid) they were very close. During the experiment, it was not observed the growth of Enterobacteriaceae and Pseudomonas. Analyzing the pH, it can be observed that the addition of 0.15% lactic acid caused a fall of the pH of 5.89 for ~5.50, enough to inhibit the microbial multiplication in the different atmospheres, except in 80/20 CO2/N2. After analyzed this results, it was concluded that MAP to 80/20% of CO2/N2 was the more effective method to increase the shelf life of the fresh poultry sausage, added or not added with lactic acid; the addition of 0.15% of lactic acid was an effective alternative for conservation of fresh poultry sausage chicken, wrapped or not in modified atmosphere

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