Salmonella from frozen dinners!
It’s been a while since I have reviewed the various risks associated with eating, but I came across this Salmonella menace a few weeks ago. The Centers for Disease Control and Prevention published a case study describing a multistate outbreak of Salmonella enterica serotype Chester due to frozen meals. In November the CDC reported that 44 people became ill in 18 states during the late spring of 2010. Molecular analysis of patient isolates indicated sole source contamination and questionnaires completed by the patients suggested that “brand A cheesy chicken and rice frozen meals” were responsible. Of the 43 patients who were followed up, 16 of them required hospitalization however no deaths were reported. On the strength of the epidemiological analysis, the company recalled the product from the shelves and the outbreak strain was identified in 8 unopened containers. Investigation into the source during the manufacturing process did not turn up any production deficiencies or a conclusive common contaminated ingredient supplier. The best guess was that a single poultry supplier was the source in the outbreak. What made this case novel was that this episode represents the first time that Salmonella enterica serotype Chester had been reported in a widespread foodborne disease outbreak.
Editorial notes by the CDC point out that there is little in the way of negligence in either the supplier or production procedures used to bring this product to market. Simple Google image searching showed that the dinner in the above graphic was the one recalled in this outbreak. The label clearly says “Keep Frozen–Must be cooked thoroughly” and is considered a “not ready to eat” meal, as opposed to the hugely convenient “heat and serve” meal. Organisms such as Salmonella enterica and Shiga toxin-producing Escherichia coli are not effectively killed by incompletely reheating in the microwave, and require actual cooking in order to render them inert. The instruction to “allow dinner to sit in the microwave for 1 minute” is also a critical part of the cooking process, and is frequently ignored by consumers. The CDC notes that this outbreak highlights the need to educate the public on safe food handling procedures, and the need to follow the instructions prior to eating these products. Consumers also, if using a microwave oven to cook these products, need to know the specifications of their appliances and to ensure that their microwave ovens are able to be safely used to cook these.