How does E. coli get into food?

Every year, Escherichia coli, Or E.coli, causes approximately 265,000 infections and 100 deaths in the United States. Many of these infections lead to foodborne illnesses. Notably, E.coli Contamination has historically caused large and notable food recalls. In 2023 alone, the United States Food and Drug Administration (FDA) recalled 72,858 pounds (33,048 kilograms) of E.coli-contaminated food.

But how E.coli getting into food first?

First of all, it is important to understand that all strains of E.coli are the same.

“E.coli are a group of common things bacteria which are found naturally in many places, including the environment, food, water, and in the intestines of humans and some animals,” FDA spokesperson Janell Goodwin told Live Science in a email. “Most E.coli are harmless and contribute to intestinal health.

However, some E.coli strains are dangerous because they produce Shiga toxinsharmful substances that can damage the digestive tract. These strains are called shiga toxin producers. E.coli (STEC). People can get sick if they eat or drink food or water contaminated with STEC, and children under 5 and adults over 65 are generally at greatest risk for serious infections.

How dangerous bacteria contaminate food

STEC can get into food in several ways. “Food goes through several stages from where it is grown or prepared to the dining table,” a spokesperson for the US Centers for Disease Control and Prevention (CDC) said in an email. at Live Science. “Contamination can occur at any stage of the chain: during production, processing, distribution or preparation.”

Goodwin noted that a major route of infection is through animals, including livestock and wildlife. Animals can carry STEC in their intestines and then excrete it in their feces. Even a tiny amount of feces on a livestock carcass can cause E.coli contamination of the resulting products made from this flesh. Ground beef, for example, presents a particularly high risk of contamination, because livestock is the main transporter of E.coli O157a particularly dangerous strain of STEC. Bacteria can be spread when meat is ground, and this led to major recalls.

Bacteria from livestock or wildlife feces can also contaminate products. For example, runoff from livestock farms can E.coli in the water used to irrigate crops. Poorly treated manure used as fertilizer can also carry harmful bacteria.

Additionally, farmworkers who come into contact with livestock or produce may unknowingly transfer E.coli during planting, harvesting or processing if they do not carefully follow security protocols aimed at preventing the transfer of bacteria from fecal contamination.

Harmful E.coli Strains can also spoil food at the other end of the food processing line, such as in a restaurant. “Carriers (who shed the bacteria in their feces) can spread infections when food handlers do not use the appropriate products. hand washing hygiene after going to the bathroom,” Goodwin said.

Stop the spread

The FDA recommends that people wash their hands with warm water and soap for at least 20 seconds before and after handling raw foods. The agency also emphasizes the importance of washing hands before, during and after changing a baby’s diaper, as well as when contacting livestock.

Countertops and cutting boards can be another source of contamination, so the FDA advises washing them thoroughly as well.

Certain foods are more likely to be contaminated with harmful substances E.coli than others. A 2021 CDC Report found that beef – particularly raw or undercooked ground beef – and row crops of vegetables, such as leafy greens, caused 80% of O157 infections in the United States between 1998 and 2021. Raw and undercooked poultry; raw shoots like alfalfa; and products made from unpasteurized or raw milk are also common culprits, Goodwin added.

Researchers are still working to better understand the factors that contribute to E.coli contamination of food supplies. A recent study found that seasonal changes in temperature can influence the probability of E.coli outbreaks linked to lettuce grown in California, while another Arizona study found that STEC can spread through the air from large livestock facilities to neighboring production farms.

Goodwin also noted that while it may be alarming to see E.coli recalls and media advisories, this does not necessarily mean that the food safety system is failing.

“The occurrence of recalls and advisories means that manufacturers, importers and distributors are monitoring problems and taking action when they detect a problem,” she said. “Consumers should be aware that recalls and outbreak notices indicate that the problem has been identified and is being resolved.”

This article is for informational purposes only and is not intended to offer medical advice.