In my career, advising food plants on the priority to control the environmental parameters increasingly has become paramount for processors. Environmental Sanitation and EM (Environmental Monitoring) has become a keystone in a plant’s internal EM programs as well as with the Global Food Safety Initiative (GFSI) and federal regulations. In my previous articles “Hygiene Monitoring Strategies that Hit the Mark” (April/May 2013) and “Be Ready to Beat Listeria” (April/May 2008), while food contact surfaces are a high priority, the environmental niches/zones have increasingly had a profound impact and role on a facility’s food safety-sanitation hygiene programs.
There are a multitude of studies that have demonstrated the ability of pathogens like L. monocytogens and Salmonella spp. to not only survive but flourish in a multitude of problematic environmental niches inherent in a wide range of food processing plants. While both types of pathogens survive via their vegetative state, not relying on spores for survival, both have their own modes for survival, persistence and biofilm formation.
As is well documented, Listerial species will persist and flourish in moist environments, and will out compete other species in temperatures below 40 degrees Fahrenheit (less than 4 degrees Celsius) being a bonafide psychrotroph gram positive, soil borne opportunist. While being a gram negative pathogen, Salmonella species have exhibited a marked tolerance for dry environs persisting in niches with lower moisture levels than Listerial species require. While not precluding the sporeforming opportunistic pathogens like B. cereus, or C. perfrigens, the other group of microbes that post persistent issues to a plant’s environment impacting food quality are the fungal species. Since most result in quality concerns rather than food safety concerns, these opportunistic environmental contaminants can profoundly impact shelf life and form biofilm alliances with a variety of bacterial pathogens. While some environmental niches are similar between vegetative pathogens and spoilage fungi, some are distinct for each group. Below is both a discussion of these environmental niches and their control measures.
Regulatory, GFSI, Product Type Perspectives
The Food Safety Modernization Act (FSMA) cornerstone is prevention akin to the proactive preventative philosophy of Hazard Analysis and Critical Control Points (HACCP). FSMA has expanded prevention to include HACCP principles to implement preventive controls. One of the key segments is sanitation controls with mandated verification and validation of the sanitation processes inherent in the operation. Preventive controls include an EM program to verify pathogen control effectiveness which includes not only food contact but environmental zones. In addition, the revision of Good Manufacturing Practices, or GMPs, to incorporate allergen cross-contact controls via preventative procedures is critical and directly involves a facility’s environmental sanitation program.
The current focus by FSMA on ready-to-eat (RTE) produce products, the fresh cut, and commodity RTE produce products is that they must rely on sanitation controls both on food contact and environs of a plant or packing house in order to control pathogens and spoilage microbes (to enhance shelf life). The cantaloupe and other produce pathogen outbreaks underscore the need for environmental sanitation as a critical preventive control.
The USDA FSIS 9 CFR Part 430 (2003 onwards) program emphasizes Lm control in RTE meat and poultry products. Alternatives 2 and especially 3 rely on sanitation measures and mandated validation and verification to demonstrate pathogen control of high-risk RTE products.
The GFSI programs, and specifically BRC and SQF, emphasize the mandatory development of environmental sanitation and validation programs. Not only do clauses 4.4, 4.7, and 4.10 deal with issues and parameters involving environmental sanitation, namely Building Fabric, Maintenance, and Filters & Sieves, but clause 4.ll on Housekeeping & Hygiene is one of BRC’s Fundamental Clauses. 4.11.1 clearly states that “documented cleaning procedures shall be in place and maintained for the building, plant, and all equipment.” Also, 4.11.2 focuses on the cleaning and disinfection procedures and frequencies shall be validated. Furthermore, in the BRC appendices, the emphasis of RTE environmental sanitation is very clear in the Guideline on Defining Production Risk Zones by delineation of High Care (Appendice 2.2) and High Risk (Appendice 2.3) in open product areas. “High-care” areas are practices inclusive of environment to minimize pathogen contamination of chilled/frozen RTE products with a high standard. High-care product examples include smoked fish, fresh prepared meals and salads, and uncooked garnishes on RTEs. This is inclusive of both FDA and USDA RTE products. “High-risk” open areas also involve RTE fully cooked products that are susceptible to cross-contamination by Listerial spp. High-risk areas are “designed to a high standard of hygiene where practices relating to…environment aim to prevent contamination by pathogenic microorganisms. High-risk product examples consist of fully cooked meats, meals, and dairy products.
SQF deals with environmental sanitation control in a comparable manner. Module 2 under Food Safety Fundamentals (a Mandatory module in both Levels 2 and 3) makes its clear the property, buildings, and equipment shall be constructed, designed, and maintained to facilitate the hygienic production…of safe food. Both for Preprocessing of Plant products (i.e. produce packing houses) in Module 10 and for food processing plants in Module 11, there is focus on the construction and control of product handling and storage areas. Module 11.2 discusses materials of construction and design for all environmental surfaces and has a specific section (18.104.22.168) on Cleaning and Sanitation which includes “The methods and responsibility for the cleaning of the food handling & processing equipment and environment, storage area, staff amenities, and toilet facilities shall be documented and implemented.” In addition, Air Quality (11.5.7) pertaining to compressed air hygiene is also emphasized by SQF.
Both BRC (Fundamental Clause 5.2) and SQF (2.8.2) clearly emphasize the high importance of allergen management, which includes proper environmental sanitation procedures and programs to prevent cross-contact onto a processing line. This becomes problematic for dry sanitation processes where wet sanitation methods are limited based on processing line and facility engineering design. SQF, BRC, and other GFSI programs separate high-risk processes (perishable RTEs) versus low-risk processes (raw or baked shelf stable).
The Environmental Zones
In high-risk operations, both the frequency and level of sanitation procedures, and standards are, of course, far more stringent than in low-risk product processing. However, we can categorize high or low-risk regardless of product type for this discussion. So let’s first focus on Zone 3 items near the food contact zone.
While there is no prescribed frequency for Zone 3 areas, based upon the proximity to the process lines, below are suggested frequencies for your Preventative Maintenance Environmental Sanitation schedule.
Zone 3 Daily Sanitation Frequencies:
- Flooring, drains, walls, and covings adjacent to equipment that is floor or table mounted.
- Processing line catch trays or bins that are used to capture soil or scraps viewed as food waste not being reprocessed into product.
- Sanitizer mats/troughs, walk-through boot scrubbers, food transport carts, plastic RTE product pallets.
- Mezzanine or elevated platforms that cross exposed processing equipment/lines.
- Hand sink areas (sink, soap, and towel dispensers) in the production facility.
Zone 3 Weekly Sanitation Frequencies:
- Cooler, floorings adjacent to the process modes.
- Overheads, ceilings, covings, walls, and hoses that are in the general area adjacent to production lines that could create an actual physical, chemical (includes allergens), or microbial cross-contamination of a product on a line.
- Air conveying equipment—includes HVAC units and their condensate pans, air hoses used for processing equipment, or drying of equipment or for packaging equipment. These are verified and validated using both surface swabs for soil and indicators and air sampling for airborne microbes.
- Cleaning equipment, which includes floor scrubbers (tank reservoirs, squeegees, and brushes especially) and condensate pads. Also refuse bins and containers.
- Control panels in close proximity to processing lines or mezzanines.
- Non-food carts.
Zone 4 areas can and do include ceilings, overheads, walls, and flooring that do not directly impact processing equipment or lines. However, the lack of a proper environmental sanitation procedure at the appropriate frequency will definitely cascade microbial and allergen (chemical) contaminants to Zone 3 and the products Zones 1 and 2. Some examples are included below, most of which are either weekly or monthly frequency based on traffic flows/usage.
Daily Zone 4 Areas: bathrooms, cafeteria and break rooms, and offices.
Weekly Zone 4 Areas: receiving docks, dry storage areas, hallways, and maintenance shops.
Monthly/Seasonal Zone 4 Areas: dry packaging storage, intake vents, overheads in nonproduction areas, and loading docks, which can be weekly if shared with receiving or if they are high volume.
A plant/facility’s design flaws both regarding product flow and traffic patterns strongly dictates the issues, frequencies, and degree of environmental sanitation required in your environmental sanitation program. The facility’s design blemishes or weaknesses will strongly dictate your risk assessment for each and every site in both Zones 3 and 4 in your plant. For example, a well-designed kettle deck mezzanine with accessible surfaces, frames, and overheads will both speed up sanitation efficiencies, and based upon proper design (i.e. 45 degree frame angles versus 90 degree), decrease sanitation frequencies of environmental Zones 3 and 4. By lowering the risk at each environmental site you also are able to decrease the Verification-Validation frequencies and procedures as well.
Both improper plant design in terms of structural issues inherent in high- to moderate-risk production areas and poor traffic floor design/practices can contribute to high risk for pathogens. For brevity, I’ll discuss the aforementioned. Salmonella for dry environs and Listeria for moist environs. Both can survive either in senescent vegetative or biofilm forms.
Salmonella can persist in a senescent vegetative state in relatively dry conditions occurring in a baking or a peanut butter processor. So there are numerous niches where it can survive. This dictates the Zone 3 or Zone 4 EM sanitation frequencies.
Examples include air lines, ducts, aspirators, and dry vacuums. Other areas include eroded or compromised walls, coving, insulation, overheads, conveyors, elevator buckets, fork lifts, and pallet trucks, cat walks, employees, cleaning tools, and maintenance tools. Also insects, rodents, and birds are carriers.
Listerial niches are created and selectively promoted by moisture and refrigerated temperatures. This includes drains, walls, covings, and hoses, gaskets, and O rings, along with unsealed structural tubing or railings. All these compromised areas promote biofilm formation, which a primary survival mode for environmental Listeria. Also improperly maintained sanitation items, such as squeegees, footbaths, floor scrubber components, condensation appliances, etc., all can be Listeria inoculators.
What’s in Your Toolbox?
In plants where wet cleaning of environmental areas is both permissible and feasible, typical foam cleaners can be employed to clean environmental surfaces.
Obviously when a prescribed wet sanitation is performed on environmental surfaces, the SSOP needs to include a sanitization/disinfection step with a compatible biocide. When the biocide will not be rinsed off, compatibility of the biocides’ chemistry must be determined with the surfaces being sanitized. For example, if one has galvanized steel and aluminum structures and you will be applying an acid based quaternary ammonium (QAC) or peroxyacetic acid (PAA), you either have to rinse it off or chose a neutral based QAC to avoid corrosion.
Application of wet biocides, especially for aqueous environmental, is dependent upon the target microbes. If they are sporeformers like B. cereus or fungi, a QAC or liquid PAA is not the preferred biocide to eliminate these sporeformers. Rather a foaming version of PAA sanitizer is preferred for all environmental surfaces. Foaming PAA penetrates sporecoats and provides enhanced residence time of the biocide on the target surfaces and attached microbes. As stated above, if one is applying foaming PAA to soft metals on a normal set frequency, after a 30 to 60 minute residence time, the foamed PAA should be rinsed off to avoid corrosion issues.
If you’re applying foaming PAA or foaming QAC sanitizers to drains, one can inject foamed sanitizer deep into trough, square, or circular drains including deep into the drain pipes. Also, when one applies QAC above 600 milligram/liter per U.S. EPA label instructions, QAC typically foams. That is why it’s utilized quite successfully in wet environments with proper drainage for door foaming units to control Listeria cross-contamination.
For those environmental areas that are either inaccessible for wet sanitation or for dry environments, fogging of biocides is a good measure to help control environmental microbes. A functional definition of fogging is the aerosolization or particles where over 80 percent are under 20 micrometers in diameter. This creates a dry mist that dries almost instantly. Prior to fogging, dry vacuuming or use of dusting attachments must first be undertaken to remove as much dust and soil as is physically possible prior to fogging. Fogging of any type of biocides should be done where the room can be confined or is feasible from a cubic meter/footage standpoint. In essence if the room’s ceiling height is 20 feet high and the room is the size of a football field, foggers cannot handle the cubic area. Fogging mandates very strict safety protocols insuring personnel are not in the room being fogged, requiring automated timing devices and a time period of 60 minutes to two hours prior to reentry into a fogged room. The application of fogged biocides includes coolers and HVAC units or cooling units in a cooling or freezer spiral. Fogged biocides penetrate deep into a HVAC unit and sanitize those environs in a HVAC system that are inaccessible for wet sanitation. Again, QAC/liquid PAA sanitizers can be effective if vegetative microbes are the primary contaminants, while activated chlorine dioxide is preferred if sporeformers, like fungi or bacilli, are an environmental contaminant issue. If the sanitizer applied in the fogging mode is above the approved food contact level then either all food contact surfaces must be draped with plastic or rinsed thoroughly post fogging. However, sometimes an approved food contact level of a fogged biocide like chlorine dioxide is sufficient, which eliminates the draping or rinsing of contact surfaces. Similar provisions need to be applied in an organic plant which requires sanitizers approved as food contact sanitizers like certified liquid PAA or chlorine dioxide sanitizers available on the market.
Giambrone is the vice president of technical services for Rochester Midland Corp.’s Food Safety division. He can be reached at cgiambrone@RochesterMidland.com.
References Furnished Upon Request