Preparing food can be a very dirty business.
People can easily spread germs from meat and poultry by touching kitchen counters, cutting boards and electrical appliances.
A new study published in the Journal of Food Protection, however, found an even greater threat to health from an unexpected place - your spice shakers.
The researchers from Rutgers University and North Carolina State University claimed in their peer-reviewed study that these containers pose a greater risk of bacterial cross-contamination when people cook. In fact, the study authors found that nearly half of the spice containers in the experiment were contaminated with the pathogen while the participants cooked the same meal in kitchens of different sizes.
The amount of bacteria that participants spread on the spice containers was higher than that found on cutting boards and trash can lids during the study.
Donald Schaffner, a Distinguished Professor in the Department of Food Science at the Rutgers School of Environmental and Biological Sciences who co-authored the study, explained that cross-contamination is the process by which bacteria move from one substance to another — usually with harmful effects.
“In addition to more obvious surfaces like cutting boards, garbage can lids and refrigerator handles, here’s something else that you need to pay attention to when you’re trying to be clean and sanitary in your kitchen,” he said. “Our research shows that any spice container you touch when you're preparing raw meat might get cross-contaminated. You’ll want to be conscious of that during or after meal preparation.
”The team said that proper food handling procedures, adherence to cooking times, constant hand washing and disinfection of kitchen surfaces and utensils can stop the spread of bacteria from uncooked food.
How was the research conducted?
The purpose of this study was to determine the prevalence and degree of contamination on a variety of kitchen surfaces during meal preparation. During the study, researchers followed 371 people who cooked the same hamburger recipe in several different kitchens. These areas ranged in size from small apartment-style kitchens to larger teaching kitchens.
Each prepared the same meal, using raw ground turkey meatballs, seasoning and prepackaged salad. To simulate the movement of pathogens across a working kitchen, the team inoculated the meat with a bacteriophage called "MS2" without the participants' knowledge.
Bacteriophages are viruses that infect bacteria, but do not pose a threat to humans. This allowed researchers to safely detect cross-contamination without putting the cooks at risk.
After each participant finished cooking their meal, the study authors scanned all kitchen utensils, surfaces and tools to search for the presence of MS2. After reviewing these results, the team decided to check additional surfaces, including spice containers and sink faucet handles.
Results showed that 48% of the spice containers sampled showed evidence of MS2 contamination. Cutting boards finished in second place and trash can lids finished in third place in terms of pollution. Faucet handles showed the lowest amount of contamination during food preparation.
“We were surprised because we had not seen evidence of spice container contamination before,” Schaffner said. “Most research on the cross-contamination of kitchen surfaces due to handling of raw meat or poultry products has focused on kitchen cutting boards or faucet handles and has neglected surfaces like spice containers, trash bin lids and other kitchen utensils. This makes this study and similar studies from members of this group more comprehensive than previous studies.”