Understanding where Listeria lives and thrives is crucial for food processors when developing strategies to prevent it.
According to the FDA, Listeria outbreaks have been linked to:
Other food products in which Listeria has been identified include raw dairy products, fruits, vegetables, deli meats, hot dogs, and seafood products.
Listeria can spread during virtually any step in the food supply chain, including:
Contamination can be caused by a range of sources, including air, water, soil, meat, and produce. During food processing and preparation, the bacteria can be spread from one food to another through contaminated cutting boards, work surfaces, and utensils. During storage and transportation, Listeria will continue to grow, even in a refrigerated environment, so food that has been contaminated can spread the bacteria to other items in cold storage or to the surfaces of refrigeration equipment. When it adheres to storage equipment surfaces, the bacteria can spread to multiple food batches, making it potentially difficult to identify the source of the contamination.
Eating food that is contaminated with Listeria can lead to a disease called listeriosis, which causes symptoms that range from mild to severe, with the risk of death for certain populations, especially pregnant women, newborns, seniors, and those with compromised immune systems. In addition to fever and mild digestive symptoms, listeriosis can also cause headaches, a stiff neck, confusion, muscle aches, loss of balance, and convulsions. The CDC estimates that 1,600 people get listeriosis and about 260 die from the disease each year.
Unlike other common foodborne pathogens, Listeria’s ability to grow under refrigeration means it can be found at many points in the food supply chain. People at every step in the process must be aware of the risks that Listeria presents and the methods for preventing its spread.
For consumers and restaurants, Listeria prevention includes:
Food processors can also use these tips and more to prevent cross-contamination in facilities.
Addressing cross-contamination is just one method for preventing the spread of Listeria in a food processing environment. Manufacturers should also implement prevention programs to avoid costly outbreaks. This includes regular sanitizing protocols to reduce the presence of bacteria to safe levels on any surface where it might grow, such as:
Best practices for sanitizing in a food processing environment include:
Sanitizers reduce bacteria to a safe level, but do not eradicate them completely. Any bacteria that are left behind have the potential to grow, spread, and develop biofilms. This is one reason daily sanitation procedures are critical for preventing the spread of Listeria. When Listeria is detected at levels that are not safe, surfaces should be treated again with a sanitizer or disinfectant to bring them to acceptable levels.
Protecting your food processing plant by preventing the spread of foodborne pathogens such as Listeria also protects your brand. To learn more about best practices for sanitizing and disinfecting in a food processing environment, read The Busy FSQA Manager’s Guide to Proactive Plant Sanitation.