Biofilms, those slimy films of bacteria that cling to surfaces, can wreak havoc on your equipment and harbor dangerous pathogens that contaminate your products. And they are not easy to detect or remove. Charles Giambrone, Food Safety Manager, Rochester Midland, shared strategies for the detection, remediation, and control of biofilms at the Food Safety Tech Hazards Conference in April.
“Biofilms are how microbes look to survive in nature and within your food plant,” said Giambrone, “and they can form quickly—within 13 hours.”
Biofilms form on any equipment with a large surface area and, in addition to contaminating food, they can damage equipment. “Once you get biofilms on the conveyor belts, you have slippage,” said Giambrone. “Just as biofilm plague will rot your teeth, biofilms form acid that corrode equipment. Eliminating biofilms can increase performance and prolong the lifespan of equipment.”
Detection of Biofilms
If you are seeing any of the following, it is a sign that you have a biofilm(s) in your facility:
- Sporadic out of spec environmental test results
- Rainbow appearance on stainless steel
- Decreased shelf life of product
- Increased bacterial count in finished product
- Spike in bacterial counts that disappear and reappear
“When you get these spikes, where the bacterial count goes down and then whips up, that is a biofilm,” said Giambrone.
Where Biofilms Like to Lurk
The most common areas for biofilm formation include dead legs, slow-moving water lines, conveyors, floors, drains, pipeline or filler gaskets, and pump valves and gasket junctions. “You must do periodic tear downs to clean gasket junctions because the CIP (clean in place system) cannot reach these areas,” he said.
Control and Remediation
Removal of biofilms requires mechanical action as well as the application of strong chemicals applied for a lengthy contact time. “You need to detach the biofilm from its surface with mechanical action,” said Giambrone. “The irreversible adhesion of biofilm prevents a CIP system’s shear flow rate forces from properly stripping biofilm from a surface.”
High water temperatures (based on the specific cleaner you are using) are necessary for removal, but Giambrone cautioned against use of the FDA-approved temperature of 180 degrees F. “You want hot water—about 130 degrees F—not scalding (180 degrees F), because scalding water fixes the protein to the surface making it harder to clean, and it’s also a safety hazard,” he said, noting that contact time is also important. “Increased contact time of cleansers/sanitizers will yield better results.”
The goal of your biofilm removal process is to detach biofilms from the surface, break down the community into small components via detergents, surfactants, and mechanical action, and then completely destroy the detached subsections via true oxidative sanitizers: PAA, chlorine or ozone.
Additional risk factors for biofilm formation include:
- Extended run operations
- Dry cleaning only during the week
- Equipment cleaned daily but not with a stringent regimen to remove biofilms
- Walls and drains not cleaned every 24 hours
The agents Giambrone recommended for biofilm remediation include: Chlorinated alkaline cleaners, acidic cleaners, EDTA (chelating agents), which remove minerals from biofilm matrix—“These are very effective in removing the biofilm from the surface,” he said—and enzymatic cleansers.