5 Targets to Test for in Your Production Environment: #3 Salmonella

#3: Salmonella

What is Salmonella?

Salmonellae are a diverse group of gram-negative bacteria in the family Enterobacteriaceae. There are two species of Salmonella (Salmonella enterica and Salmonella bongori). S. bongori is prevalent in cold-blooded animals like reptiles and rarely associated with human illness. Serotypes of S. enterica subspecies enterica (such as S. enterica subspecies enterica Serovar Enteritidis and S. Typhimurium (for short)) are found in mammals and fowl around the world and in the environment. There are over 2,500 serotypes of Salmonella enterica. These groups of Salmonellae are associated with human illness and constitute a major public health concern. A concerning development in recent years has been the emergence of antimicrobial resistant Salmonella serotypes.

Where does Salmonella come from?

Salmonellae have strongly adapted to poultry. Although affected flocks typically display no visible symptoms, they can cause foodborne illness in humans. To prevent salmonellosis, people are recommended to observe basic food preparation principles such as thoroughly cooking raw poultry products. However, recent outbreaks of salmonellosis have been associated with low-moisture foods (such as peanut butter, spices, and powdered milk). Typically, low-water activity in food creates an environment that is not suitable for pathogens to grow. How, then, are these processed products contaminated? Salmonella contamination has been linked to inadequate sanitation, poor equipment design, lack of proper maintenance, inadequate good manufacturing processes (GMPs) and the introduction of contaminated ingredients into finished products.

What kinds of process controls work to prevent Salmonella?

Traffic patterns, GMPs, sanitary design and sanitation practices are key components of a facility’s hazard analysis and critical control points (HACCP) and preventive control measures for Salmonella. Environmental testing is performed to verify the effectiveness of those control programs. It is common practice to test the production environment and processing equipment for Salmonella species. Food contact surfaces and non-food contact surfaces are tested for Salmonella species according to a robust sampling program.

It is also important periodically to test incoming ingredients for Salmonella. Accepting ingredients on Certificate of Analysis (or COA) is no longer sufficient. The United States Food and Drug Administration (FDA) requires periodic testing of incoming ingredients under the Food Safety Modernization Act (FSMA). Contaminated materials, such as powdered milk and spices, can be used as ingredients in a variety of foodstuffs and can lead to massive recalls of numerous commodities.

What methods do processors use to test?

Rapid methods that test for Salmonella species have proven reliable. Environmental monitoring provides processors with a tool to verify the effectiveness of sanitation and control programs. A majority of samples will be negative, which allows processors to continue routine operations and release their product faster. Positive test results may indicate potential hot spots or growth niches of Salmonella in the plant, indicating that corrective actions must be taken to eliminate the source of the contamination before the finished product is compromised. Processors looking to mitigate the risk of product recalls and human illness associated with Salmonella should implement an effective environmental monitoring program (EMP) and routinely test incoming ingredients and finished products for this serious pathogen.

There’s more to come! The series continues with a look at quality indicator organisms.

This article was originally published in International Food and Meat Topics, vol. 29, no. 5 (October 2018).

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