Should I wrap raw vegetables loosely or tightly before refrigerating?

Some vegetables need to be wrapped to prevent dehydration. Sometimes the advice that’s given is to wrap vegetables loosely or place them in a perforated bag to prevent the growth of spores that could cause botulism. (These are not killed by the usual cooking temperatures but any toxin that is formed would be killed by normal high heat treatments.) Bean sprouts and root vegetables--such as carrots, turnips, potatoes, and onions—are most likely to be a problem. However, the danger of contracting botulism from refrigerated raw vegetables is not great. The bacteria that cause botulism cannot grow in the presence of oxygen and do not like low temperatures (below 39°F). The risk of botulism is greater, food scientist Dr. Karin Allen explains, if (for example) you put a large container of very hot stew or chili in the fridge, and it takes a long time to cool. Put large quantities of hot food containing vegetables into a few smaller containers.

There is another reason for allowing some wrapped vegetables breathing room, explains food scientist Dr. Clair Hicks. “Humidity must be controlled on many fruits and vegetables to prevent mold growth. Too low humidity causes the produce to dehydrate too fast; too high will cause mold growth. Loose packaging helps to control humidity under refrigerated conditions.”

Some processors of mushrooms recommend refrigerating them in a paper bag (which is more porous than the plastic container and covering that they usually come in). Alternatively, you can puncture holes in the wrapping to allow the mushrooms more contact with oxygen.

Source(s):

Karin E. Allen, Ph.D., Utah State University, Dept. of Nutrition, Dietetics, and Food Sciences

Clair L. Hicks, Ph.D., University of Kentucky, Dept. of Animal and Food Sciences

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