Combined Effect of Storage Condition, Surface Integrity, and Length of Shelf Life on the Growth of and Spoilage Microbiota on Refrigerated Ready-to-Eat Products.

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.