WASHINGTON — If the mad cow found in California has you wondering about food safety, well, there are plenty of problems that pose serious risks to the food supply. But mad cow disease shouldn’t be high on the worry list.

Just in the last few months, Americans have been sickened by contaminated sprouts, raw milk and sushi. Thirty people died last year from bacteria-tainted cantaloupe. And when it comes to hamburger, a dangerous strain of E. coli that can lurk in ground beef sickens thousands of people every year.

“What we know is that 3,000 Americans die every year from preventable food-borne illnesses that are not linked” to mad cow disease, said Sarah Klein of the consumer advocacy group Center for Science in the Public Interest. “Things like E. coli, salmonella — that’s where we should be focusing our attention, outrage and policy.”

The comparable numbers for mad cow disease? Four sick cows ever discovered in the U.S., the one announced on Tuesday the first since 2006 — and no human version of the illness linked to eating U.S. beef.

“From simply a public health issue, I put it very, very low,” Cornell University food-safety expert Martin Wiedmann says of the level of concern about mad cow disease.

Maintaining confidence in exports fuels the nation’s monitoring of the beef supply as much as continuing safety concerns, he said.

Tuesday’s news came from that monitoring: Routine testing of a dead dairy cow from central California showed the animal had bovine spongiform encephalopathy, or BSE, a disease that gradually eats holes in the animal’s brain.

U.S. health officials were adamant that there was no risk to the food supply — the cow never was destined for the meat market, and the World Health Organization said humans can’t be infected by drinking milk from animals that have BSE.

The U.S. has been guarding against BSE for years, since a massive outbreak in Britain that not only decimated that country’s cattle but showed that eating BSE-contaminated meat could trigger a human version of the disease.

A key part of the safety net: The animal tissues that can carry bovine spongiform encephalopathy — including the brain and spinal cord — are removed from cattle before they’re processed for food.