Discovery by Food Scientists Improves Food Safety

Posted in Food Safety,Our Blog on May 30, 2021

An estimated 1,600 people in the U.S. get Listeria every year, and about 260 of those cases result in death. Thanks to a recent discovery by food scientists at Cornell University, there is a greater chance of prevention of further food-borne outbreaks. In a research study published on May 17^th of this year, the scientists identify 5 new species of Listeria, increasing the set of Listeria species monitored in food production environments.

What Is Listeria?

Listeriosis is a serious infection usually caused by eating food contaminated with the bacterium Listeria monocytogenes. The infection is most likely to sicken pregnant women and their newborns, adults aged 65 or older, and people with weakened immune systems. It’s rare for a healthy person to get sick with Listeria.

Listeriosis is usually a mild illness for pregnant women, but it causes severe disease in the fetus or newborn baby. Some people with Listeria infections, most commonly adults 65 years and older and people with weakened immune systems, develop severe infections of the bloodstream (causing sepsis) or brain. This can result in sepsis, meningitis, or encephalitis. Listeria infections can sometimes affect other parts of the body, including bones, joints, and sites in the chest and abdomen.

New Report Announces Five New Species of Listeria!

The new report, which identifies the 5 new species of Listeria, appears in the Journal of Systematic and Evolutionary Microbiology and effectively increases the listeria species that have to be monitored. The lead author of the study and a doctoral student in food science at Cornell, Catharine R. Carlin, explains that, expanding the knowledge base regarding these bacteria, further understanding the diversity of listeria as a genus, will save the world from confusion and errors brought about by these previously unknown species. This could help prevent contamination and explain false positives, preventing chances of foodborne disease outbreaks.

One of the five new listeria species, L. immobilis, was named “immobilis” for its lack of ability to move, a notable characteristic since listeria is known for moving around a lot. Before this discovery, motility was thought of as a universal trait among listeria. Additionally, this trait has been used in existing tests for detecting listeria and the L. immobilis was most likely undetectable under these tests. With the discovery, standard identification protocols used by food safety regulators and food facilities will have to be rewritten to accommodate the possibility of immobile species.

Since existing listeria species are usually found in the same environments that also allow L. monocytogenes to thrive, food facilities monitor for all known listeria species in the verification of their sanitation and food safety practices. For food processing plants, which must be kept strictly clean, the presence of L. monocytogenes has a profound influence on the presence of pathogens.

In a press release from Cornell University, Martin Wiedmann, co-author of the study and a professor of food safety and food science said, “This paper describes some unique characteristics of listeria species that are closely related to listeria monocytogenes, which will be important from an evolutionary perspective and from a practical standpoint for the food industry.” Wiedmann is also a part of previous studies that have led to the discovery of 13 out of 26 species currently classified within the genus listeria.

What can you do to prevent illness?

You can prevent an outbreak of Listeria at home by following some simple guidelines:

• Wash the inside walls and shelves of the refrigerator, cutting boards and countertops, and utensils that may have contacted contaminated foods; then sanitize them with a solution of one tablespoon of chlorine bleach to one gallon of hot water; dry with a clean cloth or paper towel that has not been previously used.
• In order to prevent or slow down the growth of bacteria, set your refrigerator to 40℉ and your freezer to 0℉.
• Wipe up spills in the refrigerator immediately and clean the refrigerator regularly.
• Wash hands with warm water and soap for at least 20 seconds before and after handling food and following any cleaning and sanitation process.
• Pregnant women, the elderly and those with weakened immune systems should avoid certain foods, including unpasteurized or raw milk, cheeses made from unpasteurized milk, raw fish raw sprouts and some other raw foods, which carry a high risk for Listeria.
• People with pets should take special care to avoid cross-contamination when preparing their pet’s food. Be sure to pick up and thoroughly wash food dishes as soon as pets are done eating, and prevent children, the elderly, and any other people with weak immune systems from handling or being exposed to the food or pets that have eaten potentially contaminated food.

Food Safety Is a Win For Everyone!

You can’t tell if your food is contaminated with Listeria before you eat it. However, this new study means that it will be easier for food processing and shipping companies, as well as regulatory agencies to identify the presence of Listeria before it gets to you at the restaurant or grocery store. This is a win for everybody! I, for one, certainly hope these scientists will continue their amazing work and continue to help improve food safety for everyone.

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