For years food companies have struggled with biofilm prevention. The importance of biofilm prevention cannot be underestimated and should be addressed through effective sanitation programs.  With proper implementation of the sanitation process, biofilms can be removed and prevented, and potential health risks reduced. 

Biofilms are a community of bacterial cells that adhere to each other and surfaces, protected by polysaccharides that act like glue¹. These polysaccharides allow bacteria to attach themselves to surfaces and to feed off the protein and soils that have not been removed. Bacteria such as Listeria, Salmonella, and E. coli are some of the more well-known “culprits” that cause foodborne illnesses. Spoilage bacteria will also attach themselves to surfaces and are the main contributor to shortened shelf life of food products. Even though biofilms are difficult to remove, they can be removed with the 8-Steps of Sanitation, which incorporates the 4-factors of wash, concentration, temperature, time and mechanical force. As in every aspect of problem-solving, there is no silver bullet that will address the problem exclusively. However, if the 8-Steps of Sanitation is used in conjunction with a robust monitoring program, biofilms can be removed and prevented. 

8-Steps of Sanitation

1. Sanitation Preparation and Dry Pickup
In this step it is important to remove the bulk of protein from product contact surfaces and the floor and pick up any trash, debris, or obstructions (pallets of packaging material or product) in the areas that need to be cleaned. It is critical that necessary equipment is disassembled  before cleaning is performed, and the pieces are stored properly to prevent cross-contamination. The disassembly or “breaking down” of equipment allows the inspection of hard to reach areas and enables identification of any interior niches that could cause microbial infestation or “harborage.” 

2. Pre-rinse

This step is completed to knockdown protein and soils on all equipment and lower walls, starting from the top and working down to the floor and utilizing recommended hot water temperature ranging from 120°F to 140°F and > 130 psi; which is recommended for meat processing plants. Hot water temperature should not exceed 140°F because it may bake the protein and soil to the surface, which can increase the potential for microbial growth. Protein and soil removal should be > 95% before moving to the next step.

3. Chemical Application & Hand Scrubbing

The major function of cleaning chemicals is to lower the surface tension of water so that soils may be loosened and flushed away. This step is essential for the removal of biofilms on equipment. Cleaning chemicals help disintegrate any remaining proteins and soil, and hand scrubbing will continue that breakdown by releasing debris from the surfaces for an easier rinse down. Some key tips for step three:

• Ensure proper foam application from bottom to top on all equipment. 
• Foam should be left on the equipment for 10-15 minutes, but do not let the foam dry on the equipment.
• Hand scrubbing should be completed while the foam is on the equipment or with a separate scrub bucket of general purpose cleaner and a scrub pad.
• Scrubbing drains should be performed during this step.
• End of Hose titrations should be conducted and properly documented daily.

During the chemical application and hand scrubbing, it is important to consider the four factors of wash.

Four Factors of Wash

1. Concentration – Concentration of cleaning chemicals should be within the manufacturer’s specified use range to effectively help penetrate, breakdown, and remove soils/debris.
2. Temperature – Water temperature affects the effectiveness of soil removal and chemistry activation.
3. Time – Time it takes for cleaning chemicals to adequately penetrate, breakdown, and remove soils from a surface.
4. Mechanical Force – Refers to the optimal water pressure or utilization of a scrub pad during the sanitation process to assist with the breakdown and removal of soils and debris on surfaces. There are also other options like CIP (Clean in Place) and COP (Clean Out of Place). Keep in mind that optimal water pressure may not be available; therefore, it is imperative that the concentration, temperature, and time meet the proper ranges to be effective.

4. Post Rinse & Inspect

During this step, it is recommended to rinse the foam from all surfaces starting at the top and working the cleaner down to the floor and utilizing recommended hot water temperature ranging from 120°F to 140°F and > 130 psi: which is recommended for meat processing plants. Using high volume/low pressure hot water, all chemicals, proteins and soils should be removed, targeting 100% removal. A best practice during the rinse step is to inspect equipment using flashlights to verify the removal of protein and soils. 

5. Assemble & Condensation Removal

This is the time that production, maintenance and Sanitation work together to reassemble equipment following proper hygienic procedures and GMPs and to remove condensation and standing water. A best practice directly after this step would be to conduct a flood rinse of equipment prior to preoperational inspection.

6. Preoperational Inspection

When conducting the pre-operational inspection, the use of a flashlight, organoleptic senses, and hands are helpful in verifying the cleanliness of equipment. This is an extremely important step to help identify any missed opportunities during the cleaning process and address it immediately. Pre-operational inspection is not merely walking up and down a line with a flashlight at eye level. An excellent robust pre-operational inspection consists of bending down to inspect lower framework, inside of belts, or hard to see locations. Climbing ladders to get to the overhead belts or structures that you cannot see thoroughly from the floor. During the inspection process, you would need to use your sense of smell, touch, and sight along with any tools possible to increase the opportunity of identifying any deficiencies prior to turning the floor over to the plant. 

7. Final Sanitizer Application

The last step to help prevent and control biofilms is the application of a no-rinse level sanitizer. It is important that the sanitizer is titrated prior to application to ensure regulatory compliance by following the manufacturer’s label requirements. Apply the no-rinse level sanitizer prior to the start of production from the bottom to the top with 100% coverage of all product contact and non-contact surfaces. Be sure to include the underside of equipment, high inside framework, and niche areas. 

8. Documentation
The last step to help prevent and control biofilms is the application of a no-rinse level sanitizer.  It is important that the sanitizer is titrated prior to application to ensure regulatory compliance by following the manufacturer’s label requirements.  Apply the no-rinse level sanitizer prior to the start of production from the bottom to the top with 100% coverage of all product contact and non-contact surfaces.  Be sure to include the underside of equipment, high inside framework, and niche areas. 

Characteristics of Soils

There are other factors to consider when implementing the 8-Steps of Sanitation that have a tremendous impact on the cleanliness of the plant.  First, let’s look at the characteristics of soil and soil attachment. The soil or protein must be identified prior to starting the 8-Steps of Sanitation. The optimum water temperature range will depend on the type of soil and protein found on plant surfaces. The range commonly used in meat plants is 120°F to 140°F with a target of 130°F to remove soils and proteins. The type of soils and proteins will also determine which detergent or cleaner is used.  Once you have identified the characteristics of the soil, you will also need to factor in water hardness before selecting the detergent or cleaner that will best fit the process. Water hardness is primarily composed of calcium and magnesium salts in water​. As the surface dries, hard water causes water spots on the equipment, and when reacting with soap can form soap scum. Water hardness deactivates detergents and can negatively affect sanitizers and disinfectants. This is where certain chemical products are formulated to tie up the calcium and magnesium ions so that the cleaner or sanitizer can tolerate water hardness¹. Once the soil or protein is identified, and water hardness is factored in, then the 8-Steps of Sanitation can be implemented. Though, there are still some hurdles ahead that will need to be addressed for optimum prevention.

Soil Attachment and Sanitary Design

Sanitary design plays a crucial part in the prevention of biofilms. Food equipment must be constructed to ensure effective and efficient cleaning over the life of the equipment. The equipment should be designed to prevent bacterial entry, survival, growth and reproduction on both product and non-product contact surfaces of the equipment. ​ Soil removal becomes more difficult when there are cracks, crevices, uneven surfaces, or hard to clean areas, such as rough welds, broken welds, pitted metal, hollow framework, or rollers. These cracks and crevices become niches or harborage points that make the cleaning process more extensive. Additional tools for cleaning and specific chemical compounds can be used but will not completely remove what could be embedded within these hard to clean areas. This is when plant management, food safety, and Sanitation must partner to identify these areas for immediate repair or replacement to ensure these areas do not create harborage for bacteria. An example of a simple repair would be to cap off the hollow framework that is being used as legs for tables or on framework for belts. Of course, best practice would be to systematically remove hollow framework and replace it with angle iron for easy access to cleaning. Another example is to smooth out rough welds to eliminate small holes or pitted areas. In order for the cleaner to be effective at separating the soil from the surface, the soil and surface must be thoroughly wet, which is sometimes difficult if the surface is hard to reach or fails to be free of niches or harborage points.

Construction Events

Another factor that should be taken into consideration is construction events. Anytime a construction event is planned in a plant, a strategy needs to be developed to ensure that any potential risks are identified prior to construction. This plan should also have preventions in place for each identified risk. A coordinated effort among Operations, Maintenance, Food Safety & Quality Assurance (FSQA), and Sanitation is necessary to develop and implement a plan that prevents uncovered biofilms from becoming a problem after the construction event is over. Construction events have the tendency to uncover or loosen up hidden biofilms that have been embedded in floors, walls and equipment due to poor sanitary design or extensive wear and tear over the years. The construction plan should also incorporate a chemical “script” specific in addressing the area of concern. This chemical “script” not only has the 8-Steps of Sanitation and the 4-factors of wash but also includes intensified cleaning. Intensified cleaning includes but is not limited to:

• Breaking equipment down to the “bare bones,” which is the removal of all sandwiched parts.
• Use of specific chemicals to address specified equipment, areas and microbial problems. Success is measured by the results of how close the strategic plan was followed.

Conclusion

In preventing biofilms from taking over any production area, there is no “one size fits all” scenario. It takes a reliable sanitation program, a dedicated sanitation team, a partnership with production, maintenance and Sanitation, and diligence to stay on top of identified harborage locations. Starting with the 8-Steps of Sanitation, including the 4-factors of wash, biofilms can be reduced to a prevention level. Keep in mind other factors that will impact the removal of biofilms, such as sanitary design and construction events. Furthermore, utilizing sanitation resources such as contract cleaning companies can be a valuable addition to biofilm reduction and prevention efforts.

Candy Lucas is a Sr. Food Safety Director for PSSI, A Food Safety Solution Company
Image credit: ©stock.adobe.com/au/Kateryna_Kon
References:¹N.G. Marriott et al., Principles of Food Sanitation, 6^th ed. Springer Scientific: New York, NY