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A Journal of Infectious Diseases paper co-authored by Bill Keene about an investigation into a norovirus outbreak that hit 13 members of a soccer team has created a media furor and a press release competition. Itcould have been a gym bag, or a plastic bag - but the implicatedvector happened to be a reusable grocery bag that was left in ahotel room that contained a bunch of food. Cue the witch hunt on reusable bags. The Academy of Nutrition and Dietetics recycled a recent press release saying that reusable bags need to be washed regularly by users aspathogens grow well and cross-contamination is likely. From the release: Reusable grocery totes are a popular, eco-friendly choice totransport groceries, but only 15 percent of Americans regularlywash their bags, creating a breeding zone for harmful bacteria,according to a survey by the Home Food Safety program, acollaboration between the Academy of Nutrition and Dietetics(formerly the American Dietetic Association) and ConAgra Foods. "Cross-contamination occurs when juices from raw meats orgerms from unclean objects come in contact with cooked orready-to-eat foods like breads or produce," says registereddietitian and Academy spokesperson Ruth Frechman. "Unwashedgrocery bags are lingering with bacteria which can easilycontaminate your foods." I don't dispute that washing bags is a good idea, I'm just not surethere's data that supports their statements. Williams and colleagues (2011) have published the only peer-reviewed study on the microbialsafety of reusable bags and tested growth of Salmonella in 2batches. They spiked the bags with 10^6 cfu and let them sit in thetrunk of a car for 2 hours. One of the batches, where thetemperature reached 47C/117F, showed a one-log increase in theSalmonella. The other batch, where the temperature reached53C/124F, there was a one-log reduction. That data doesn't showjust a breeding zone - it shows they can be a killing zone too (andI'm not sure how realistic a 10^6 contamination really is). The part of the press releases that is the least rooted in scienceis that pathogen-containing bags "easily contaminate yourfoods." The same Williams study showed generic E. coli isfloating around in bags, recoverable in 12 % (n=58) of those testedbut can it be (or is it likely) to be transferred to anyready-to-eat foods, or somehow to food contact surfaces in thehome? Just because the bacteria might be there, doesn't mean it cancontaminate a ready-to-eat food. No one has presented data tosupport that. Maybe the Academy of Nutrition and Dietetics - if so,they should share it. In a cross-contamination event there is a dilution effect when itcomes to transfer. 1000 cfus of Campylobacter on the outside of thepackage of raw chicken might become 100 cfus when transferred tothe bag, and then only 10 cfus when transferred to ready-to-eatapples. Washing bags frequently (as the Academy of Nutrition and Dieteticssuggests) is probably a good idea (like washing hands in warmwater) and probably won't increase risk, but I wonder how much itdecreases the probability of cross-contamination when compared todoing nothing. Aron Hall from CDC took a much more realistic approach to the outbreak focusing on norovirus (as opposed to the vector)calling the virus "the perfect human pathogen." Icouldn't agree more, as I cleaned up puke over the past couple of days . The e-commerce company in China offers quality products such as China Auto Dry Cabinet , China Nitrogen Dry Box, and more. For more , please visit Flammable Storage Cabinet today!
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