If I had to guess the most feral part of my kitchen, I’d probably say it’s my creepy garbage disposal. (I once found a rotten quarter of lemon lodged in there.) But I would be wrong. One study published late last year found that the biggest germ magnet in your kitchen is, in fact, your spice jars.
The researchers didn’t see it coming either. “We were surprised because we had not seen evidence of spice container contamination before,” Donald Schaffner, PhD, a food science professor at Rutgers School of Environmental and Biological Sciences, told Food Safety News. “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.”
Commissioned by the Department of Agriculture to understand how cross-contamination occurs, the team of researchers observed 371 people as they all cooked identical turkey burgers in kitchens of various sizes, ranging from smaller apartments to larger industrial settings. The recipe involved seasoning raw, ground turkey patties—which had been inoculated with a harmless tracer virus known as MS2—and putting together a prepackaged salad.
The participants had no idea they were in a food safety trial; they were told they’d be testing out a new recipe. But once they’d finished the meal prep, researchers swabbed 12 different kitchen surfaces (which had been thoroughly sanitized before cooking), including counters, utensils, cutting boards, sinks, and spice containers. The degree of cross-contamination varied wildly: The pathogen MS2 was found on most surfaces 10%–20% of the time—but a whopping 48% of spice containers were contaminated.
The authors note various possibilities for the high concentration of MS2 found on spice containers. It “could be due to their close proximity to the region in which turkey patty handling occurred, the lack of attempts made to wash hands between handling the ground turkey and seasoning the patties with the spices, the lack of attempts made to clean or sanitize the spice containers after handling, and the high number of times the containers were handled,” the study says.
So what does this all mean for home cooks? Benjamin Chapman, an author on the study who also leads the department of agricultural and human sciences at North Carolina State University, told The Washington Post that people don’t need to freak out and fumigate their spice drawers. Pathogens tend to lose their harmful potency on surfaces, and the inoculated turkey was designed to simulate a “worst-case scenario.”
That said, Chapman suggested people should wash their hands more, not just before and after cooking, but during too. If, like me, you’re slack with hand-washing, give your spice jars a just-in-case clean—especially considering an estimated 20% of foodborne illnesses are acquired at home. Then remember to clean a jar if you use it right after handling raw meat or eggs. Chapman told The Post that people should wipe down their spice jars with a soapy cloth and finish with a disinfecting kitchen spray. While you’re at it, check the expiration dates: The spices in your cabinet are probably stale anyway, so maybe it’s also time for a restock.
Unbounded spice-shaking is definitely part of being a great cook. I am reluctant to admit, so is cleaning up after yourself.