Would you rather eat chicken contaminated with Salmonella or deli meat contaminated with Listeria monocytogenes? What about choosing between a hamburger contaminated with E. coli O157:H7 or turkey contaminated with Campylobacter jejuni? Let’s dive into what makes these foodborne pathogens dangerous and why we work hard every day to ensure a safe food supply.

Foodborne pathogens are microorganisms that cause illness when you eat or drink contaminated food and beverages. The type of illness can range from mild discomfort to severe health complications to death.

Anyone can get a foodborne illness, but certain groups of people are more likely to get very sick. Healthy adults generally have a strong immune system to fight off bad bugs. However, if your immune system is not in tip-top-shape, your body may struggle to get rid of the microbes easily.

The state of your immune system is perhaps the most significant factor in how sick you get if you eat contaminated food. Groups of people at increased risk of severe illness are children under 5, people aged 65 and older, pregnant women, and those with a weakened immune system from underlying health conditions.

So which foodborne bacteria pose the most risk? If you look at the estimated number of illnesses, hospitalizations, and deaths, Salmonella and Campylobacter are the top bacteria of concern. They each cause over a million illnesses, thousands of hospitalizations, and hundreds of deaths. So just by shear numbers these bacteria are the greatest overall risk to public health.

Now even though Listeria monocytogenes produces less than 300 illness a year, it has a much higher mortality rate. This means that if you get sick from Listeria monocytogenes, you have a greater chance of dying from this bacteria. For comparison, mortality rates of Campylobacter = <1%, Salmonella = 1-3%, E. coli O157:H7 = 3-5%, and Listeria monocytogenes = 15-30%. Moreover, pregnant women are 10 times more likely to get a Listeria infection.

Where does E. coli O157:H7 fit in? Compared to Salmonella and Campylobacter, it causes a lot less illnesses and deaths, but it is a leading source for hospitalizations. It also has a bigger effect on children and the elderly; Kidney failure impacts 1 out of 7 children under age 5 with an E. coli O157:H7 infection. Another noteworthy characteristic of this bacteria is that it has a very low infectious dose. Infectious dose is the number of cells needed to trigger an illness. You can get sick from ingesting only 10-100 cells of E. coli O157:H7.

All four of these bacteria are bad bugs for good reasons. Salmonella and Campylobacter cause the largest number of foodborne illnesses each year. Listeria monocytogenes has the highest mortality rate and disproportionately affects at-risk groups of people. E. coli O157:H7 can make you sick with a very small number of cells and children are more likely to have severe health complications. For these reasons (and more!) we work with our customers to help prevent foodborne pathogens from contaminating our food.