Comparison of environmental regulatory requirements for Salmonella and L.mono

Ensuring the safety of our food is crucial, and the food industry must effectively control the spread of harmful pathogens like Salmonella and Listeria monocytogenes. The regulations governing these bacteria differ based on the type of food product and jurisdiction. This article will delve into the specific regulatory requirements for both Salmonella and Listeria, emphasizing the key differences and important measures in place. 

Health risks associated with Salmonella and Listeria in food  

Both Salmonella and L. monocytogenes can infect and persist at any point from farm to consumer. That's why it's crucial to be aware of the dangers of these pathogens and take steps to reduce the risk of foodborne illness. Many produce recalls, such as spinach and lettuce, have occurred in the past three years due to Salmonella and L. monocytogenes contamination. Here are some of the recent recalls:   

" Health authorities in Ireland are looking into a Salmonella outbreak that has affected over 20 individuals. Laboratory tests have confirmed 26 cases, and the affected people fell ill between November 30 and December 25, 2022."  


" More than 300 people from 16 countries have been sickened in a Salmonella outbreak linked to Kinder chocolate made in Belgium. "   


L. monocytogenes also marked some serious headlines: 

"Switzerland revealed a Listeria outbreak in 2022 which caused illness in 20 and resulted in one fatality."  


"Daniele International LLC, based in Mapleville, Rhode Island, is recalling 52,914 pounds of ready-to-eat (RTE) sausage products due to Listeria monocytogenes contamination (2023)."  


In severe cases, Salmonella and Listeria can cause serious health complications, including sepsis, meningitis, and even death, particularly in vulnerable populations such as young children, older adults, pregnant women, and those with weakened immune systems. Additionally, Salmonella infection can be obtained from multiple food and non-food sources, such as contact with infected animals, including pets. Therefore, to protect consumers and public health, it is vital to have risk assessment, control, and prevention measures in place throughout the food chain. Good hygiene practices during food handling, storage, and distribution are also critical to prevent the spread of bacteria.  

The presence of Listeria monocytogenes and Salmonella in food processing environments differs significantly. Listeria monocytogenes is commonly found in some food factories, with a positive rate ranging from 10% to 30% of environmental swabs. At the same time, Salmonella is comparatively rare, with a prevalence rate as low as 0.01%. This disparity should be considered when using tests to detect Salmonella in food processing environments. A negative result does not indicate a failure but rather the low prevalence of Salmonella in these environments. 

Read also: Where to find Salmonella in food production

Differences in environmental regulations for Salmonella and Listeria in the food industry  

Whether you are a food producer, distributor, or consumer, it is essential to understand the regulations that govern the food you eat to ensure it is safe and free from harmful bacteria. With the information in this article, you can better understand the measures in place to protect public health and ensure the safety of the food supply.  

European Union  

In the European Union (EU), there are regulations for the acceptable levels of Salmonella and Listeria monocytogenes in food products, including ready-to-eat products. These specific regulations for environmental monitoring are outlined in several critical pieces of legislation, including:  

  • Regulation (EC) No 852/2004 on the hygiene of foodstuffs 
  • Regulation (EC) No 2073/2005 on microbiological criteria for foodstuffs
  • Good Manufacturing Practices (GMPs)
  • Hazard Analysis and Critical Control Points (HACCP)   

In general, the EU regulations for environmental monitoring require regular monitoring of food contact surfaces and equipment, sanitation procedures, and record-keeping to ensure compliance with food safety standards. 

For Listeria monocytogenes, the EU allows for a limited tolerance in ready-to-eat products, with a maximum limit of 100 colony-forming units (CFU) per gram. This is based on the understanding that even with good hygiene practices, the pathogen can still be present in small amounts in food products. This balance acknowledges that the public likely consumes some quantity of Listeria monocytogenes in their daily diet, and it is unrealistic to enforce a 0 tolerance. Although most people, including vegetarians, likely consume small amounts of Listeria monocytogenes regularly, they do not experience adverse effects as they have robust immune systems. Conversely, low quantities of Salmonella in ready-to-eat products can be dangerous and cause infections, unlike the case with Listeria monocytogenes 

For Salmonella, there is a zero-tolerance for foodstuffs. According to Regulation (EC), No 2073/2005, Salmonella is considered a hazard to public health and must not be present in foodstuffs for human consumption. Salmonella can be particularly dangerous for specific populations, including young children, older adults, pregnant women, and people with weakened immune systems. Even mild salmonellosis can have serious consequences for these groups, including hospitalization and long-term health problems. Food production facilities must take appropriate corrective actions to prevent recontamination if any positive results are obtained during environmental monitoring.  

United States  

In the United States, there is a zero-tolerance policy for Listeria monocytogenes in ready-to-eat (RTE) foods, which means it should be absent in 25-gram samples (less than 0.04/g). The US Food and Drug Administration (FDA) enforces this standard, regardless of whether a food supports L.mono growth. These guidelines include Good Agricultural Practices (GAPs) and Good Manufacturing Practices (GMPs) to limit the presence of these pathogens in food products. Past risk assessments and the increasing demand for RTE foods by vulnerable populations influence the zero-tolerance policy for L.mono in the US. In 2008, the FDA released draft guidance documents on Listeria, which are still under review. 

For Salmonella, there is no set tolerance level in food products. Still, the presence of Salmonella in certain food products is considered an "adulterant" by the FDA. If Salmonella is found in a food product, it violates the law, and the product may be subject to recall or seizure. However, the USDA's Food Safety and Inspection Service (FSIS) has a zero-tolerance policy for Salmonella in raw meat and poultry products. Food production facilities must implement measures to prevent contamination, including regular monitoring and testing. If a positive result is obtained, the product must be removed from the food supply and not sold to consumers. Generally, foods that are more likely to be contaminated with Salmonella, such as raw poultry and eggs, must be cooked to an internal temperature high enough to kill the bacteria. The FSIS has established guidelines for cooking these foods to reduce the risk of foodborne illness. 


The regulations for Salmonella and Listeria monocytogenes differ in their specific requirements and objectives, but both aim to minimize the risk of illness and ensure that food products are safe for consumption. Therefore, food producers must adhere to these regulations and implement effective food safety programs to minimize the risk of contamination and ensure that consumers can have confidence in the food they purchase. 

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