This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
How safe was your last meal? If you dined out, you took a significant risk.
The Centers for Disease Control estimates 76 million Americans acquire foodborne illnesses annually. In the U.S., 3,334 incidences of outbreaks from 1998 to 2002 were reported in restaurants or delicatessens according to a Morbidity and Mortality Weekly Report. And recent research by food safety specialist Ben Chapman of North Carolina State University found that meals prepared in commercial kitchens have been involved in up to 70 percent of food poisoning outbreaks.
These figures led Chapman and his team to use video surveillance to take a closer look at how food handlers follow guidelines. Their study featured observations of 47 handlers in eight commercial kitchens. After examining 348 hours of such surveillance, the researchers concluded in the June issue of Journal of Food Protection that "the prevalence of cross-contamination is a hidden problem for food service."
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Indirect cross-contamination, which transfers pathogens such as Salmonella and E. coli from kitchen equipment to ready-to-eat food, made up 89 percent of all contamination events that the team observed. Bacteria transfer peaked during busy hours, occurring on average up to two times per hour during breakfast rushes. Incidents of indirect cross-contamination rose to more than three times an hour during lunch periods. "It is important data for communicators because indirect cross-contamination is a complicated process to explain and isn't focused on in training materials enough," says Chapman.
The study recommends food safety practices be viewed in a "team-like nature," which the group says is currently missing from training materials. It is uncommon to have one person in a commercial kitchen work on a meal from start to finish, yet food handlers tend to operate as individuals. This resulted in contaminated surfaces being re-used by different people involved in a meal's preparation. Chapman says since these kitchens are made up of multiple players, workers need to be aware of each others' actions to prevent cross-contamination.
Chapman's team also compared food handlers' actions before and after safety information sheets were posted in visible areas of the kitchens. Indirect cross-contamination decreased by almost 20 percent and hand washing increased by about 7 percent.
In addition to posting safety information to reduce risks, other solutions include increasing preparation time to lessen pressure on cooks during peak hours and installing hand sanitizer units in accessible spots of kitchens. The team even suggests utilizing the study's observation method—video monitoring—along with "interviews focusing on food safety knowledge, attitudes, and intentions." Chapman says companies can use the study's results as a baseline and compare it to the actions taking place in their own kitchens. More video observation can keep food handlers aware of their actions—and keep cross-contamination out of commercial kitchens.
Image courtesy of iStockphoto/lisegagne
