There have been two national recalls recently of commercially frozen vegetables due to potential contamination with the pathogen Listeria monocytogenes. On August 26, 2015, General Mills recalled 60,000 packages of Cascadian Farm Cut Green Beans after one package of finished product tested positive for the presence of Listeria monocytogenes. The 10-ounce bags of frozen green beans were processed in 2014 and printed with either of two “Better If Used By” dates marked on the package: 10APR2016 or 11APR2016. The Cascadian Farm frozen cut green beans were distributed to retail establishments nationwide.
Then, on August 31, 2015, the Food and Drug Administration and Bonduelle USA announced a recall on frozen corn (cut and whole kernel) due to contamination with Listeria monocytogenes. Products affected are sold under the Wylwood, Market Basket, Bountiful and West Creek brands.
How does this happen? Listeria monocytogenes is an organism which can survive on equipment and in the warm, moist environment of a food processing facility. While careful cleaning and sanitation are designed to remove contamination from equipment and the processing environment, Listeria can be very persistent. The blanching process prior to freezing of corn, green beans, and other vegetables destroys pathogens which might be on raw vegetables as they enter the processing facility. In these cases of product recall, contamination of frozen vegetables most likely occurred after blanching, and as a result of contact with contaminated equipment during freezing or handling after freezing.
What does this mean for consumers? Consumers should always cook frozen vegetables prior to consumption. Thorough cooking will destroy the Listeria which may be on frozen product. Use boiling water and the stove-top method for cooking frozen vegetables; a microwave may not heat frozen vegetables enough to destroy the pathogen. Don’t be tempted to thaw and add frozen (un-cooked) vegetables to dishes. If you are making the church-favorite potluck disk of macaroni salad with frozen peas, be sure to thoroughly cook the peas and then cool them before adding them to the salad.
Listeria, a rare but deadly germ, is the 3rd leading cause of death from food poisoning. The Centers for Disease Control and Prevention has more information on protecting your health from this potentially deadly bacterium. The CDC also has Spanish-language information available. Stay food safety! Barb