Essential oils are effective antimicrobials on important some pathogenic bacteria and can be added packaging materials due to absorb various surfaces. In this study, the aim is to determinate of antimicrobial effects ...Essential oils are effective antimicrobials on important some pathogenic bacteria and can be added packaging materials due to absorb various surfaces. In this study, the aim is to determinate of antimicrobial effects of methyl cellulose films with containing various proportions thyme, rosemary, coriander, basil and pimento berry oils （1%, 2%, 3% and 4% g/cc） against important bacteria as a surface contaminant Listeria innocua by in vitro. For this purpose, 1 cm diameter discs were cut from methyl cellulose films containing essential oils and inhibition zone diameter which were measured by the agar diffusion method. As the results of these analyses, all prepared active edible methyl cellulose films were antimicrobial effects on Listeria innocua. The most powerful antimicrobial effect achieved with methyl cellulose film including coriander oil on Listeria innocua. And also the weakest antimicrobial effect achieved with methyl cellulose film including rosemary oil on Listeria. All results were significant by statistically （p 〈 0.01） and all analyses were replicated in three times.展开更多
Floor drains in processing environments harbor Listeria spp. due to continuous presence of humidity and organic substrates. Cleaning and washing activities in food-processing facilities can translocate the bacterial c...Floor drains in processing environments harbor Listeria spp. due to continuous presence of humidity and organic substrates. Cleaning and washing activities in food-processing facilities can translocate the bacterial cells from the drain to the surrounding environment, thus contaminating food products still in production. This study evaluated the potential for translocation of Listeria monocytogenes from drains to food contact surfaces in the surrounding environment using Listeria innocua as a surrogate. A 7 × 7 × 8-foot polycarbonate flexi-glass chamber with a 10-inch-diameter drain mounted on an aluminum cabinet was used. Stainless steel coupons (6.4 × 1.9 × 0.1 cm, 12 per height) were hung at 1, 3, and 5 feet inside the chamber. Four treatment sets;non-inoculated, non-treated;non-inoculated, treated;inoculated, treated;inoculated non-treated;and two subtreatments of 8 h and 48 h were performed. For the inoculated sets, meat slurry (10 gof ground beef in 900 mL water) and a four-strain cocktail of Listeria innocua at 7 - 8 log CFU/mL were used. For the treated sets, in addition, a commercial cleaner and sanitizer was applied. The drain was cleaned using a pressure hose (40 - 50 psi) after 8 h and 48 h. Coupons were then removed and enriched in listeria enrichment broth to establish if any cell translocated from the drain onto the stainless steel coupons via aerosols generated during washing. Confirmation was done using VIP Listeria rapid test kits. Results indicated translocation at all three heights ranging from 2% - 25%. Significantly higher translocation (p Listeria spp. from drains to food contact surfaces does occur and increases with increased proximity to the drain.展开更多
Meat is a rich nutrient matrix that provides a suitable environment for proliferation of meat spoilage microbiota and common food-bom pathogens, therefore adequate preservation has to be applied in order to preserve i...Meat is a rich nutrient matrix that provides a suitable environment for proliferation of meat spoilage microbiota and common food-bom pathogens, therefore adequate preservation has to be applied in order to preserve its safety and qualib：. Lantibiotic nisin is not conunonly used in the meat industry, in spite of its beneficial effect in e.g. dairy industry. Theretbre, here, the effect of nisin was searched in traditional fermented sausage Gombasek experimentally contaminated with Listeria innocua Lil strata Ihe antimicrobial effect of nisin was demonstrated by the Lil strain decrease at day 2 （after contamination） with the difference 1.79 logarithmic （log） cycles comparing with the control sausage （CLi）. At week l, the difference 4.14 log cycles was noted in the experimental sausages comparing with CLi sausages with prolonging inhibitory effect up to week 2; although the difference was diminished （1.82 log cycles）; but higher than at day 2, The pH values as well as lactic acid values were not influenced by the nisin treatment （pH value in the reference sausage was 5.0, in CLi 5.7 and in the experimental sausage E, 5.1; amount of lactic acid in t： was 0.099 mmol L^-1： and in CLi 0.107 mmol L^-1）.展开更多
本研究利用高分辨率熔解曲线的方法,以iap基因为靶标新设计一对引物同时鉴别单增李斯特氏菌、伊氏李斯特氏菌和英诺克李斯特氏菌,其余14种常见食源性病原微生物扩增为阴性结果,单增李斯特氏菌和伊氏李斯特氏菌的检出限为10个拷贝,英诺...本研究利用高分辨率熔解曲线的方法,以iap基因为靶标新设计一对引物同时鉴别单增李斯特氏菌、伊氏李斯特氏菌和英诺克李斯特氏菌,其余14种常见食源性病原微生物扩增为阴性结果,单增李斯特氏菌和伊氏李斯特氏菌的检出限为10个拷贝,英诺克李斯特氏菌的检测限为50个拷贝。本研究对78份样品进行HRM-realtimePCR法、GB4789.30-2016和SN/T1870-2016(荧光PCR法)的检测,并对3种方法的检测结果进行统计学分析。结果显示:HRM法和国标方法、HRM法和荧光PCR法的检测结果之间存在统计学差异,国标方法和荧光PCR法检测结果之间无统计学差异。本研究建立的基于HRM-real time PCR法检测3种李斯特氏菌的方法快速高效、特异性好、成本低,适用于食品中李斯特氏菌的日常检测和监管。展开更多
To test the feasibility of radiant energy vacuum （REV） dehydration, a technology that couples microwave cooking with vacuum pressure, on beef jerky preparation, the physical and microbial properties of the final jer...To test the feasibility of radiant energy vacuum （REV） dehydration, a technology that couples microwave cooking with vacuum pressure, on beef jerky preparation, the physical and microbial properties of the final jerky product was compared to conventional preparation methods. Physical characteristics assessed using puncture and shear tests of samples prepared using REV dehydration compared to the traditional method were not statistically different （P 〈 0.05）. Moisture content and water activity levels were also very similar between the two products, To test microbiological quality, samples were homogenized in a stomacher and a variety of 3 M Petrifilms were used to evaluate the microbial load. Raw beef harboured low numbers of microbes, but the post-marination pasteurization/smoking step used in both treatments eliminated all culturable microorganisms tested for. To further investigate the ability of REV dehydration to kill microbes, samples were spiked with Listeria innocua after the pasteurization/smoking step but prior to REV dehydration. Samples were taken at different time intervals for microbial enumeration, and a decimal reduction time of 1 min was calculated, with 99.99% of 1.98 × 10^7 CFU g^-1 Listeria being killed in five min. Improved drying times were observed for jerky samples prepared using the REV method offering potential energy savings during jerky preparation.展开更多
文摘Essential oils are effective antimicrobials on important some pathogenic bacteria and can be added packaging materials due to absorb various surfaces. In this study, the aim is to determinate of antimicrobial effects of methyl cellulose films with containing various proportions thyme, rosemary, coriander, basil and pimento berry oils （1%, 2%, 3% and 4% g/cc） against important bacteria as a surface contaminant Listeria innocua by in vitro. For this purpose, 1 cm diameter discs were cut from methyl cellulose films containing essential oils and inhibition zone diameter which were measured by the agar diffusion method. As the results of these analyses, all prepared active edible methyl cellulose films were antimicrobial effects on Listeria innocua. The most powerful antimicrobial effect achieved with methyl cellulose film including coriander oil on Listeria innocua. And also the weakest antimicrobial effect achieved with methyl cellulose film including rosemary oil on Listeria. All results were significant by statistically （p 〈 0.01） and all analyses were replicated in three times.
文摘Floor drains in processing environments harbor Listeria spp. due to continuous presence of humidity and organic substrates. Cleaning and washing activities in food-processing facilities can translocate the bacterial cells from the drain to the surrounding environment, thus contaminating food products still in production. This study evaluated the potential for translocation of Listeria monocytogenes from drains to food contact surfaces in the surrounding environment using Listeria innocua as a surrogate. A 7 × 7 × 8-foot polycarbonate flexi-glass chamber with a 10-inch-diameter drain mounted on an aluminum cabinet was used. Stainless steel coupons (6.4 × 1.9 × 0.1 cm, 12 per height) were hung at 1, 3, and 5 feet inside the chamber. Four treatment sets;non-inoculated, non-treated;non-inoculated, treated;inoculated, treated;inoculated non-treated;and two subtreatments of 8 h and 48 h were performed. For the inoculated sets, meat slurry (10 gof ground beef in 900 mL water) and a four-strain cocktail of Listeria innocua at 7 - 8 log CFU/mL were used. For the treated sets, in addition, a commercial cleaner and sanitizer was applied. The drain was cleaned using a pressure hose (40 - 50 psi) after 8 h and 48 h. Coupons were then removed and enriched in listeria enrichment broth to establish if any cell translocated from the drain onto the stainless steel coupons via aerosols generated during washing. Confirmation was done using VIP Listeria rapid test kits. Results indicated translocation at all three heights ranging from 2% - 25%. Significantly higher translocation (p Listeria spp. from drains to food contact surfaces does occur and increases with increased proximity to the drain.
文摘Meat is a rich nutrient matrix that provides a suitable environment for proliferation of meat spoilage microbiota and common food-bom pathogens, therefore adequate preservation has to be applied in order to preserve its safety and qualib：. Lantibiotic nisin is not conunonly used in the meat industry, in spite of its beneficial effect in e.g. dairy industry. Theretbre, here, the effect of nisin was searched in traditional fermented sausage Gombasek experimentally contaminated with Listeria innocua Lil strata Ihe antimicrobial effect of nisin was demonstrated by the Lil strain decrease at day 2 （after contamination） with the difference 1.79 logarithmic （log） cycles comparing with the control sausage （CLi）. At week l, the difference 4.14 log cycles was noted in the experimental sausages comparing with CLi sausages with prolonging inhibitory effect up to week 2; although the difference was diminished （1.82 log cycles）; but higher than at day 2, The pH values as well as lactic acid values were not influenced by the nisin treatment （pH value in the reference sausage was 5.0, in CLi 5.7 and in the experimental sausage E, 5.1; amount of lactic acid in t： was 0.099 mmol L^-1： and in CLi 0.107 mmol L^-1）.
文摘本研究利用高分辨率熔解曲线的方法,以iap基因为靶标新设计一对引物同时鉴别单增李斯特氏菌、伊氏李斯特氏菌和英诺克李斯特氏菌,其余14种常见食源性病原微生物扩增为阴性结果,单增李斯特氏菌和伊氏李斯特氏菌的检出限为10个拷贝,英诺克李斯特氏菌的检测限为50个拷贝。本研究对78份样品进行HRM-realtimePCR法、GB4789.30-2016和SN/T1870-2016(荧光PCR法)的检测,并对3种方法的检测结果进行统计学分析。结果显示:HRM法和国标方法、HRM法和荧光PCR法的检测结果之间存在统计学差异,国标方法和荧光PCR法检测结果之间无统计学差异。本研究建立的基于HRM-real time PCR法检测3种李斯特氏菌的方法快速高效、特异性好、成本低,适用于食品中李斯特氏菌的日常检测和监管。
文摘To test the feasibility of radiant energy vacuum （REV） dehydration, a technology that couples microwave cooking with vacuum pressure, on beef jerky preparation, the physical and microbial properties of the final jerky product was compared to conventional preparation methods. Physical characteristics assessed using puncture and shear tests of samples prepared using REV dehydration compared to the traditional method were not statistically different （P 〈 0.05）. Moisture content and water activity levels were also very similar between the two products, To test microbiological quality, samples were homogenized in a stomacher and a variety of 3 M Petrifilms were used to evaluate the microbial load. Raw beef harboured low numbers of microbes, but the post-marination pasteurization/smoking step used in both treatments eliminated all culturable microorganisms tested for. To further investigate the ability of REV dehydration to kill microbes, samples were spiked with Listeria innocua after the pasteurization/smoking step but prior to REV dehydration. Samples were taken at different time intervals for microbial enumeration, and a decimal reduction time of 1 min was calculated, with 99.99% of 1.98 × 10^7 CFU g^-1 Listeria being killed in five min. Improved drying times were observed for jerky samples prepared using the REV method offering potential energy savings during jerky preparation.
