Ceylan Erdogan, McMahon Wendy, Garren Donna M
1 Mérieux NutriSciences, 3600 Eagle Nest Drive, Crete, Illinois 60417; and.
2 American Frozen Food Institute, 2000 Corporate Ridge, Suite 1000, McLean, Virginia 22102, USA.
J Food Prot. 2017 Sep;80(9):1550-1556. doi: 10.4315/0362-028X.JFP-16-517.
Thermal inactivation of Listeria monocytogenes and Salmonella was evaluated on peas, spinach, broccoli, potatoes, and carrots that were treated with hot water and steam. One gram-positive bacterium, L. monocytogenes, and one gram-negative bacterium, Salmonella, were selected as pertinent human pathogens for evaluation. Samples were inoculated with a composite of five strains each of L. monocytogenes and Salmonella to achieve approximately 10 to 10 CFU/g. Inoculated samples were treated with hot water at 85 and 87.8°C and with steam at 85 and 96.7°C for up to 3.5 min. A greater than 5-log reduction of L. monocytogenes and Salmonella was achieved on all products within 0.5 min by hot water blanching at 85 and 87.8°C. Steam blanching at 85°C reduced Salmonella populations by greater than 5 log on spinach and peas within 2 min and on carrots and broccoli within 3.5 min. Populations of Salmonella were reduced by more than 5 log within 1 min on carrot, spinach, and broccoli and within 2 min on peas by steam blanching at 96.7°C. Steam blanching at 85°C reduced L. monocytogenes populations by more than 5 log on carrots and spinach within 2 min and on broccoli and peas within 3.5 min. L. monocytogenes populations were reduced more than 5 log within 1 min on carrot, spinach, peas and broccoli by steam blanching at 96.7°C. Longer treatment times and higher temperatures were required for steam-blanched samples than for samples blanched with hot water. Results suggest that hot water and steam blanching practices commonly used by the frozen vegetable industry will achieve the desired 5-log lethality of L. monocytogenes and Salmonella and will enhance microbiological safety prior to freezing.
在经热水和蒸汽处理的豌豆、菠菜、西兰花、土豆和胡萝卜上评估了单核细胞增生李斯特菌和沙门氏菌的热失活情况。选择一种革兰氏阳性菌——单核细胞增生李斯特菌和一种革兰氏阴性菌——沙门氏菌作为相关的人类病原体进行评估。将单核细胞增生李斯特菌和沙门氏菌的各五种菌株的混合物接种到样品中，以使每克样品达到约10⁵至10⁶CFU。对接种后的样品分别在85和87.8°C下用热水处理，以及在85和96.7°C下用蒸汽处理，处理时间长达3.5分钟。通过在85和87.8°C下进行热水烫漂，在0.5分钟内所有产品上的单核细胞增生李斯特菌和沙门氏菌均实现了大于5个对数级的减少。在85°C下进行蒸汽烫漂，2分钟内菠菜和豌豆上的沙门氏菌数量减少了大于5个对数级，3.5分钟内在胡萝卜和西兰花上减少了大于5个对数级。在96.7°C下进行蒸汽烫漂，1分钟内在胡萝卜、菠菜和西兰花上以及2分钟内在豌豆上，沙门氏菌数量减少了超过5个对数级。在85°C下进行蒸汽烫漂，2分钟内在胡萝卜和菠菜上以及3.5分钟内在西兰花和豌豆上，单核细胞增生李斯特菌数量减少了超过5个对数级。在96.7°C下进行蒸汽烫漂，1分钟内在胡萝卜、菠菜、豌豆和西兰花上，单核细胞增生李斯特菌数量减少了超过5个对数级。与用热水烫漂的样品相比，蒸汽烫漂的样品需要更长的处理时间和更高的温度。结果表明，冷冻蔬菜行业常用的热水和蒸汽烫漂方法将实现对单核细胞增生李斯特菌和沙门氏菌所需的5个对数级致死率，并将在冷冻前提高微生物安全性。
