Seek and Destroy: Best Practices for Controlling Environmental Pathogens

No Niches. According to (North) American Meat Institute’s (N)AMI’s Equipment Design Task Force, “All parts of the equipment shall be free of niches such as pits, cracks, corrosion, recesses, open seams, gaps, lap seams, protruding ledges, inside threads, bolt rivets and dead ends. All welds must be continuous and fully penetrating.”

The method to identify growth niches and harborage sites is the Seek and Destroy investigation, which is used to find pathogenic growth niches, find potential growth niches requiring monitoring and control, define normal level of disassembly, define periodic deep levels of disassembly, define the frequency of periodic deep levels of disassembly, qualify a new piece of equipment (usually, run for 90 days then conduct Seek and Destroy Investigation); validate effectiveness of equipment cleaning protocol; and validate effectiveness of intervention applied to a piece of equipment (heat treatment or other method).

The sanitary design of the equipment during disassembly may be evaluated using the (North) American Meat Institute Equipment Design Task Force Checklist or another method.

In a Seek and Destroy Investigation:

1. Pre-number or pre-code sample collection bags.
2. Take a picture of the bag to indicate the next sample site to be taken.
   1. Get a distance picture to locate the site within the plant area. Take several more pictures up to a closeup of the site itself.
   2. Document the name of the site. Typically a maintenance person is the best resource for properly naming sites.
3. Repeat step 2 with each consecutive site

Understanding Movement

The movement of people, equipment, product, and materials during production operations provides motility for organisms—they move along a pathway by vectors from transfer point to transfer point. Movement from a harborage site also occurs deep within equipment or facility to the exposed processing environment. Sampling during production finds the organism moving from its preoperational state to a contact surface, the product, or a drain. The process flow of the vectors dictates the direction of movement.

Disruptive events such as rinse down at breaks even with sanitizer may physically remove many organisms from equipment. However, this activity does not eliminate the organism from the environment. Rinsing does relocate the organism, however, providing more pathways of movement.

Verification sampling during production of Z1, Z2 and Z3 pathways verifies the ability of the sanitation process control to minimize the transfer and movement of the organism.

To prevent or minimize movement, create a torturous pathway that maintains a high concentration of sanitizer on the floor and includes hurdles such as sole scrubbers between hygienic zones. Also consider captive footware, separation and segregation of transport equipment, and keeping floors dry.

Implement a Process Control for Environmental Pathogens

Figure 3. Seek and Destroy Process
Image credit: FoodSafetyByDesign, LLC

The final pillar of environmental pathogen control defines how the gains are being held while continuing the risk reduction process. The cost of pathogen sampling has and continues to drop. Pathogen sampling of verification and indicator sites are composited. History and data analysis have identified those most optimal and risky areas to sample on a regular basis. Not-for-cause investigations continue ensuring any process changes are done without increasing microbial risk. APC testing is fine tuned to recognize any shifts in the environment. Shifts that are found lead to the application of interventions and aggressive sampling.

The visual of the S&D Process as a whole is presented in the Figure 3 flow chart.

S&D Process best practices—process control (not-for-cause) investigation. The S&D Process can be conducted in situations where food safety has not been compromised. Examples include when samples are taken to find a new growth niche, find a new transfer vector/pathway, establish or qualify a hurdle or barrier system, establish a monitoring procedure or process, and assess or characterize risk of a control procedure, part of facility or process change.