The norovirus isn’t the only infectious disease sneaking up to harm the health of unsuspecting Americans.

Over the past six months, America’s once safe food supply—from whole foods including plums, peaches and nectarines to processed foods like bagged salads, cheeses, salsa, peanut butter, fruit pies, hummus and pre-packaged meals—has been plagued by the harmful foodborne L. monocytogenes bacterium, better known as listeria.

Unfortunately, this latest outbreak of listeria doesn’t have any boundaries, as major grocers, including Target, Trader Joe’s, BJ’s, Costco, Hy-Vee, Sam’s Club, Whole Foods, Wegmans and Giant Eagle, have sold foods that have been recalled due to potential contamination.

Listeria popped up on the radar of food safety experts and consumers most notably in 2011 when an outbreak infected cantaloupes grown at Colorado-based Jensen Farms that sickened 147 Americans in 28 states, including 40 in the Centennial state.

Of those who were sickened, 33 people died and a pregnant woman suffered a miscarriage, culminating in the worst foodborne outbreak in the U.S. in at least a century.

The human targets of listeria

Listeria is a very hardy bacteria—it can survive even in refrigerated and freezing environments—and is very common in our environment, yet very few Americans (1,600) are sickened by it annually.

Symptoms range from the light—fever, muscle aches, nausea and diarrhea—to the more serious—headaches, stiff neck, loss of balance, confusion and convulsions—and the incubation period could stretch out to 70 days. Yet, pregnant women may only feel a mild flu.

However, in the right environments, listeria can be very deadly, as it is the third leading cause of death from food poisoning. Patients at the greatest risk of harm:

• Pregnant women and their newborns
• People with weakened immune systems
• Seniors age 65 and older

The six ways to avoid listeria infections

The good news: People who are prone to develop more serious problems due to listeria or other food poisoning issues can take some very simple steps to avoid them:

1. Avoid unpasteurized (raw) milk or soft cheeses.
2. Refrigerate any leftovers within two hours and reuse them in no longer than four days.
3. Maintain the same low temperatures in your refrigerator (40 degrees Fahrenheit or lower) and freezer (0 degrees or lower) with a thermometer.
4. Don’t eat hot dogs and deli meats until they’re steaming hot.
5. Avoid eating risky foods by monitoring websites like Foodsafety.gov.
6. Take a multi-species probiotic like EndoMune Advanced Probiotic or EndoMune Advanced Junior for kids can help prevent infections caused by contaminated foods by boosting your intestinal immunity.