Improving Environmental Controls

Total percentage of testing from zone 1 is normally 10 to 20 percent.

Zone 2 refers to nonfood-contact areas that are closely adjacent to product-contact surfaces. In general, this is the area where environmental contamination is most likely to affect the safety of the product (e.g., equipment framework, maintenance tools, drip shields and chain-guard housings, etc.). The focal point of zone 2 testing will be to validate sanitary design of the equipment. These are the areas in the framework that collect food particles, but are not easily broken down for proper cleaning.

Total percentage of testing from zone 2 is normally 40 to 50 percent.

Zone 3 refers to nonfood-contact surfaces that are not close to zone 1 surfaces (e.g., walls, floor, drains, air handling units, etc.). If zone 3 is contaminated with a pathogen, it could lead to contamination of zone 2 through employees’ actions or movement of machinery. Zone 3 monitoring will indicate if there is a weakness in building design or poor employee sanitary practices. Areas of concern might include buildup in overheads, around extraction units, around ventilation fans, or floor areas, and handoff between sanitation and production, maintenance and production, employee entrance and production, or storage (freezers/coolers/dry) and production.

The total percentage of testing from zone 3 would be around 30 to 40 percent.

Zone 4 refers to the areas remote from product processing areas (e.g., office areas, locker rooms, maintenance rooms, etc.). If zone 4 is not maintained in a good sanitary condition, it can lead to cross-contamination of zones 1, 2, and 3. Zone 4 is not considered a high risk of potential cross-contamination.

Apart from zones 1 to 4, periodic air, office areas, water, and plant employee hand swab samples should be monitored for indicators as well as pathogens. Zone 1 could also be tested for pathogens. However, if zone 1 is tested positive for pathogens, then the product made on that line must be held until further confirmative test results are available. If the final confirmative results are positive, then it is likely a recall situation.

Using Indicator Microorganisms

Indicator microorganisms are routinely used to determine the potential presence of pathogens and to assess the effectiveness of cleaning and sanitation practices. Some benefits of using indicator microorganisms include:

• Non-pathogenic and sophisticated containment facilities or labs (e.g., Bio Safety Level-2) are not needed for sample analysis,
• Low concentrations of pathogens in the environment make them difficult to detect using current testing methods,
• Indicator microorganisms are high in numbers and can be easily enumerated,
• They are valid representation of pathogens of concern since they use nearly the same pH, nutrients, temperature, water, etc. as pathogens, and
• Laboratory tests are generally faster and less expensive.

Examples of indicator microorganisms that can be used to monitor hygienic conditions in an EMP are total aerobic plate count, total coliforms, fecal coliforms, and Enterococcus spp. of fecal origin. Indicator microorganisms are not a substitute for testing pathogens. A positive result indicates conditions for pathogen contamination and a risk of foodborne illness is plausible.

Sampling and Frequency

Environmental information or data is obtained using a vast spectrum of approaches, ranging from a simple settling plate (sedimentation), to sophisticated indicator swabs that forecast the presence of specific pathogenic bacteria in a given establishment. There are a number of methods and tools that can be used for environmental monitoring. The choice of methods/tools depends on the type of facility, type of food products, pathogen of concern, etc. The common sampling tools that can be used to evaluate the overall sanitary condition of the facility includes sterile swabs, sponges, air sampling units, RODAC plates, ATP (adenosine triphosphate) bioluminescence assay kits, etc. More sampling and testing does not necessarily mean more safety. Always follow hygienic procedures (e.g., wear sterile nitrile gloves) while collecting environmental samples. Determining frequency of sampling (daily, weekly, bi-weekly, monthly, quarterly, etc.) and the time of sampling (at what time during the shift) are the most vital parts of the EMP. Once the EMP is fully implemented it should be verified for its effectiveness. If the current sampling plan and frequency fails to meet the expected result, then the frequency and number of samples per zone should be modified to achieve the target.

Labeling and Shipping

The environmental monitoring team should receive proper training on sampling. Microbial supply companies or accredited laboratories will often come to your facility on an annual basis to train and calibrate sampling tools. Once the environmental samples are collected, write the sampling date, location, device used, sample size, list of testing requests, date submitted to the lab, etc. on the sampling bag for easy identification. Always submit a negative control swab (i.e., a swab not being used). Also, it is important to ship the collected samples as soon as possible (overnight shipping) in a sterile plastic bag with ice packs in it, but keep the ice from directly contacting the outside of the sample bags. It is important to keep the samples cool (less than 40 degrees Fahrenheit) to prevent microbial growth.