No single approach effectively controls biofilm in food processing facilities

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Food processors and manufacturers have a mission to supply quality and safe food to consumers.

The journey to succeed in that mission, however, is different for each company. Each ingredient, manufacturing process, facility and finished product brings unique food safety challenges and current good manufacturing practices (cGMPs) to address them.

However, there is a common enemy that thrives in most food manufacturing plants. Biofilm, a naturally-occurring mass of pathogens protected by an extracellular polymeric substance (EPS), attaches to surfaces and resists disinfection attempts.

Biofilm warning signs
When inspectors from the Food and Drug Administration — or certified third-party organizations — visit food facilities, they are not specifically looking for biofilm, which is invisible to the naked eye. Inspectors are trained to recognize conditions that would indicate a biofilm is present, such as food residue on equipment and other surfaces, as well as drains because they are notorious for harboring biofilms.

“We would look at whether the sanitation programs are effective, including whether the company conducts testing for indicator organisms where high counts could indicate inadequate sanitation and possibly biofilms,” according to an FDA spokeswoman. “We often take our own swabs if we see questionable conditions.”

If samples show high pathogen counts after sanitation, it’s likely they are protected by a biofilm and not free-floating organisms. Areas where water hasn’t drained is another red flag, she said.

It’s key that food safety plans prevent conditions that favor the establishment and growth of biofilm.

“Establish and implement good cGMPs and sanitation control programs, consider an evaluation of the cleanability of equipment when conducting the hazard analysis, and develop cleaning programs that prevent biofilm formation,” the FDA spokeswoman said.

Methods to control biofilm
If biofilm is present in a food processing facility, there are a number of ways to attack the EPS and pathogens. Bob Forner, director of marketing for Hunt Valley, MD-based Sterilex, said methods carry varying degrees of success. Sterilex manufactures microbial control products that not only attack the pathogens in biofilm, but also the EPS structure. If the protective structure remains intact, pathogens can repopulate the biofilm within two days, Forner said.

Key ways to respond to biofilm in a food facility are:

• Hand scrubbing: A soap/detergent can help break down the EPS, and elbow grease lifts the structure from the surface. This is very labor-intensive, and some areas are difficult to access for hand scrubbing, Forner said. Although the protective housing is attacked with hand scrubbing, an Environmental Protection Agency-registered sanitizer is necessary to kill the microorganisms housed in the structure.
• Heat: An autoclave-type treatment, heating a surface to at least 265 degrees Fahrenheit, is effective. This requires a significant use of energy, and many materials and equipment in a food facility cannot be heated to the necessary temperature, Forner said.
• Chemical oxidation: Oxidizing sanitizers and disinfectants fall into two categories, according to Sterilex. EPS-reactive oxidizers such as bleach, iodine and ozone are harsher on equipment and do not fully penetrate the biofilm structure, and EPS-penetrating oxidizers pass through the biofilm layers to kill pathogens. They are unable to kill both the EPS and the pathogens, he said.
• Biofilm agents: Sterilex’s PerQuat technology is EPA-approved to kill biofilm organisms and remove the biofilm from surfaces. The patented chemistry combines an oxidizer, hydrogen peroxide, and a phase transfer catalyst, quaternary ammonium, to penetrate the biofilm and release the peroxide to kill organisms inside.
• Maintenance/Prevention: Although the Food Safety Modernization Act, enacted more than 10 years ago, doesn’t address biofilms, regulations are designed to focus on preventing conditions that could lead to foodborne illness outbreaks caused by pathogens in them.

“FSMA focuses on control of hazards and biofilms that may contain pathogens would be addressed through sanitation preventive controls that are required in many food safety plans, as well as the cGMPs,” the FDA spokeswoman said.

A combination of these steps is the most effective way to address biofilm in a food facility, Forner said.

“Hand scrubbing and maintenance programs are a part of just about every food processing master sanitation plan,” Forner said. “Combing these methods with the appropriate EPA registered chemistry is a powerful way to keep biofilm out of the food processing facility.”

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