Why There Are So Many Frozen Food Listeria Recalls Recently

From slivered onions to organic carrots to cucumbers, the spate of food recalls has many people concerned about the safety of our fresh food supply, but less concerned about frozen foods. After all, haven't we all been warned that the "danger zone" — the optimal temperature for bacterial growth — is between 40 and 140 degrees Fahrenheit? However, recent recalls of frozen chicken products, followed by pancakes and waffles, and more meat and poultry products for listeria contamination have made it clear that this is one foodborne bacteria that doesn't abide by that rule. Unlike Salmonella or E. coli, Listeria monocytogenes continue multiplying until reaching 0 degrees Fahrenheit. Below that temperature, Listeria will stop growing, but the bacteria is not killed off. Once it comes back up in temperature, it reactivates. This also means Listeria will keep growing even in refrigerated foods.

Listeria can get into food while it is being grown, harvested, processed, packaged, or handled. In addition to continuing to grow in the refrigerator, it can also cross-contaminate any surface with which it comes into contact. That's why listeria contaminations don't just impact frozen foods. For instance, in October 2024, Costco recalled smoked salmon for listeria contamination and soft cheeses sold at Aldi and other stores were recalled shortly after for the same reason.

Experts have placed the blame for the rise in listeria outbreaks in frozen foods on several factors. One is an increase in the amount of said food products we consume and the longer shelf lives of those commercially frozen foods. Although the surge in sales from the pandemic has slowed down, the frozen foods industry still saw a 5% increase in volume in 2023 — a growth rate surpassing that of all food sales, according to a Conagra Brands report.

Many also blame the agencies responsible for ensuring the safety of our food supply: the U.S. Food and Drug Administration and the U.S. Department of Agriculture. Some say that deregulation of food safety rules under the Trump administration has led to less oversight, fewer inspections, and lax enforcement. Additionally, experts suggest that improvements in detection technology may be making it easier to catch connected cases of foodborne illnesses, spurring more recalls. 

Foods most likely to be affected by listeria contamination are those that are unpasteurized or uncooked before consumption. This includes soft cheeses, deli meats, pre-made deli salads, smoked fish, and more. Keep in mind symptoms of listeria infection do not start until at least two weeks after consumption of contaminated foods (via CDC). Listeriosis symptoms include fever, flu-like symptoms like muscle aches and fatigue, headaches, a stiff neck, confusion, and a loss of balance.