As per the 2009 food code, leafy greens are identified as a food that requires time and temperature control for safety, particularly for retail locations. This is due to the growth of pathogens that can arise without proper temperature control, as internal fluids and nutrients are sensitive to bacteria once the leaf is cut. Studies reportedly show that E. coli 0157:H7 can become attached to the stomata and cut edges of the leaves. For temperature control, this specific strain of E. coli will decrease with storage temperatures between 39-41 degree Fahrenheit, but will increase with higher temperatures.
These issues can arise in multiple areas of product, including the field, cleaning and cooling facilities, distribution warehouses, vehicles, and/or retail food locations. Overall, the consensus is that refrigeration at 41°F or below prevents the growth of such pathogens. Any greens stored above 41°F curbs bacterial growth, and can also help deactivate other bacterial presences over a period of time. For bagged and fresh-cut greens, the shelf life in a retail establishment is set at approximately 2-3 weeks. The tricky part is, these bacterial strains and spoilage isn't visually present when examining the greens, therefore putting the responsibility on the retail establishment to ensure the safety of the greens. As per the FDA, keep these receiving, storage and recommendations in mind for the quality control of leafy greens. Check out the official Retail Food Protection page on the FDA's website for more information.
Cut leafy greens must be received at a temperature of 41ºF (5ºC) or less and be free of evidence of previous temperature abuse (3-202.11).
- This requirement does not apply to the receipt of whole heads of lettuce and other raw agricultural commodities.
- Refusal of products containing cut leafy greens when proper temperatures can not be assured is one way of achieving compliance with this requirement.
Suppliers of commercially-processed, cut leafy greens generally recommend transport and storage of their product at temperatures below the 41ºF (5ºC) limit established in the Food Code.
Cut leafy greens must be maintained at temperatures of 41ºF (5ºC) or less during cold storage and display (3-501.16).
- To verify proper cold holding, measure the product temperature using an appropriate temperature measuring device. A thin probe thermocouple can be inserted in thicker stem portions of the leaf for a valid reading. An infrared (IR) thermometer can also be used to measure the surface temperature of the leaves. IR thermometers may not be as accurate in measuring the temperature of bagged product as the packaging material can cause reflections of the IR beam. For sealed bags of product, insert a thermometer stem or thermocouple probes between bagged products or fold the bag tightly around the probe to ensure adequate contact with the product.
- Refrigerators and cold storage units in which cut leafy greens are stored should be equipped with air temperature monitoring devices that allow them to be checked for proper operation and temperature control.
If fresh leafy greens are cut or chopped within the food establishment, the cut product must be discarded if not sold or served within 7 days of the time the product was cut (3-501.18). The product must be marked to indicate the date by which disposal is required, unless the cut product is held less than 24 hours from the time it was cut. (3-501.17)
If a container of commercially processed and packaged cut leafy greens is opened in a food establishment, the product must be discarded if not sold or served within 7 days of the time the package was opened (3-501.18). The product must be marked to indicate the date by which disposal is required, unless the product is held less than 24 hours from the time the container is opened. (3-501.17)
To reduce the risk of pathogen growth, maintain cut leafy greens at 41 ° F (5 °C) or less during storage and display. Routinely monitor the temperature of the product and the equipment used to maintain product temperature.
1The 2009 Food Code defines “cut leafy greens” as fresh leafy greens whose leaves have been cut, shredded, sliced, chopped, or torn. The term “leafy greens” includes iceberg lettuce, romaine lettuce, leaf lettuce, butter lettuce, baby leaf lettuce (i.e., immature lettuce or leafy greens), escarole, endive, spring mix, spinach, cabbage, kale, arugula and chard (7). The term “leafy greens” does not include herbs such as cilantro or parsley. Lettuce and other leafy greens cut from their root in the field with no other processing are considered raw agricultural commodities (RACs) and are not included in the definition of “cut leafy greens” and are therefore not considered a PHF/TCS Food, as defined and applied in the 2009 Food Code.
All above sections are taken directly from the FDA website, which can be viewed here.