A new study commissioned by the U.S. Department of Agriculture’s Food Safety and Inspection Service (FSIS) has shown that consumers may need to rethink how they handle their spice containers.

The study found that spice containers can easily and often become cross-contaminated with pathogens during food preparation.

The study, “Cross-Contamination to Surfaces in Consumer Kitchens with MS2 as a Tracer Organism in Ground Turkey Patties,” published in the Journal of Food Protection sought to determine the prevalence and degree of cross-contamination across a variety of kitchen surfaces during meal preparation.

The study was led by Donald Schaffner, Rutgers Agricultural Experiment Station’s Extension Specialist in Food Science and Professor in the Department of Food Science at the Rutgers School of Environmental and Biological Sciences. His research found that when consumers are preparing meals, spice containers can easily become cross-contaminated with health-threatening microorganisms, something he believes consumers should keep in mind.

“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,” Schaffner 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 researchers said they believe proper handling of food — including adequate cooking, consistent handwashing and sanitizing of kitchen surfaces and utensils — can combat cross-contamination.

The study methods
Researchers monitored 371 adults cooking an identical turkey burger recipe in several kitchens of various sizes, ranging from small apartment-style kitchens to larger teaching kitchens, in extension centers and food banks. Participants prepared a meal consisting of raw ground turkey patties with a seasoning recipe, along with a prepackaged salad. 

To simulate the movement of a pathogen across a kitchen, researchers inoculated the meat ahead of time with a bacteriophage, a viruses that infect bacteria and have no effect on humans, known as “MS2” to serve as a tracer.

Participants weren’t informed that researchers would be examining their food safety behaviors until after they had prepared the meal. once the meal had been prepared, researchers swabbed kitchen utensils, cleaning areas, and kitchen surfaces to test for the presence of the MS2 tracer. based on observations of participants’ behavior during cooking, researchers decided to take samples from some new categories of surfaces, such as spice containers and sink faucet handles.

The findings
The researchers found the most frequently contaminated objects were spice containers, with about 48 percent of the samples showing evidence of MS2 contamination. This prevalence of contamination was significantly different from many other surfaces sampled. Cutting boards and trash can lids were the second and third most contaminated. Faucet handles were the least contaminated object studied.

“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.”

The full study can be found here.