1 Department of Food Science, Cornell University, Ithaca, New York 14853.
2 Department of Extension, The Ohio State University, Wooster, Ohio 44691, USA (ORCID: https://orcid.org/0000-0003-1141-4746 [A.B.S.]).
J Food Prot. 2019 Aug;82(8):1423-1432. doi: 10.4315/0362-028X.JFP-18-576.
Psychrotolerant growth of in ready-to-eat (RTE) foods increases the risk to food safety, particularly when spoilage does not occur prior to growth of >1 log CFU/g. The purpose of this study was to evaluate the relative rates of quality deterioration and growth in six product systems (tomatoes, apples, fresh-cut cantaloupe, fresh-cut lettuce, baby spinach, and commercially processed turkey slices) under various conditions of refrigeration temperatures, atmospheres, and quality. Cantaloupe and spinach leaves supported >1 log CFU/g growth of before product spoilage at both 4 and 9°C. In some cases, conditions that improved microbial quality by extending shelf life also allowed growth of >1 log CFU/g before deterioration due to microbial spoilage. For example, storage with modified atmosphere packaging enhanced growth relative to spoilage microbiota in lettuce leaves (1.0-log increase 7 days before spoilage). In contrast, the use of secondary quality produce (i.e., apples, tomatoes, and lettuce with physical damage) reduced shelf life and, consequently, limited the time for proliferation. Therefore, spoilage cannot be considered a fail-safe indicator or proxy for limitation of shelf life across refrigerated RTE products.
在即食 (RTE) 食品中，耐冷菌的生长会增加食品安全风险，尤其是在变质发生之前，其生长量超过 1 个对数 CFU/g 时。本研究旨在评估在不同冷藏温度、气氛和质量条件下，六种产品系统（番茄、苹果、鲜切哈密瓜、鲜切生菜、婴儿菠菜和商业加工火鸡片）中质量恶化和 的相对增长率。在 4°C 和 9°C 下，哈密瓜和菠菜叶中的 生长量超过 1 个对数 CFU/g，超过了产品变质的水平。在某些情况下，通过延长货架期来改善微生物质量的条件也会导致 在微生物变质之前生长超过 1 个对数 CFU/g。例如，与生菜叶中的变质微生物相比，使用改良气氛包装可以促进 生长（在变质前 7 天增加 1 个对数）。相比之下，使用次级质量产品（即具有物理损伤的苹果、番茄和生菜）会缩短货架期，从而限制 的增殖时间。因此，变质不能被视为冷藏 RTE 产品货架期限制的安全指标或替代指标。
