It is now well established that bacteria, including foodborne pathogens, predominantly grow in biofilms, their natural habitat. Biofilms are comprised of dense, complex, multi-species populations of microorganisms that are irreversibly attached to a surface or to each other and are embedded in a self-produced extracellular polymeric matrix. Within biofilms, bacteria of both the same and different species communicate and interact with each other, exchange genetic material, and are much more resistant to antimicrobials than they would be in a planktonic, or unattached state. Like humans and animals, microorganisms benefit from this community-based lifestyle for growth and survival. In food processing environments, biofilms represent a persistent source of product contamination and cross contamination through detachment or aerosolization of bacterial cells.
While biofilms form more readily in warm, moist environments, microorganisms and biofilms can survive in a desiccated state. A common misconception is that biofilms are less likely to be found in low moisture environments. This is untrue, and products manufactured in dry environments are still susceptible to contamination with biofilms and associated microorganisms. In fact, once biofilms are in this dried state, metabolism is reduced, and the cells and spores persist longer (months to years), and are more difficult to eradicate, than in a high moisture environment. Upon rehydration of low moisture foods or ingredients, conditions are favorable for the growth of the previously dormant microorganisms. The recent outbreak and contamination of dry infant formula with Cronobacter species underscore the risks associated with biofilms in dry or low-moisture processing.
Studies have shown that dry surface biofilms are less susceptible to killing by heat treatment and high hydrostatic pressure than hydrated biofilms[2,3]. Typical cleaning and sanitizing methods, which are wet procedures, are not applicable in these low humidity, dry environments. Thus, steps should be taken to control biofilms and microbiological contamination in ingredients before the dry manufacturing process, which should include proper disinfection and sanitization of environmental surfaces and equipment associated with ingredient manufacturing. Various dry methods for cleaning, sanitizing, and disinfecting do exist, including dry powdered products, quick-drying sanitizers, and physical methods. Another important element in risk management is verification and environmental monitoring, including monitoring for biofilms.
Day-to-Day Pathogen Control in Dry Environments
Sterilex’s proprietary powder portfolio includes Sterilex Ultra Step and its newly launched quat-free dry sanitizer, ProvaStride. Both products are EPA-registered solid floor sanitizers specifically designed for low-moisture environments to limit the spread of pathogens throughout a facility by people and equipment.
Benefits of Sterilex Ultra Step and ProvaStride
- EPA-registered solid sanitizer effective against foodborne pathogens including Listeria monocytogenes, E. coli, Salmonella enterica, Cronobacter sakazakii, Campylobacter jejuni, and others.
- Effective against a variety of listed viruses
- Easy to use
- Adds traction and prevents slippage
- Fine, sand-like crystals provide complete coverage
- Blue color for easy identification
- Compatible with wastewater systems
Common applications of dry floor sanitizers
- Entryway control, plant floors, floor mat/boot pan sanitizer
- Processing areas
- Warehouses and loading docks
- Trash areas
- Transition areas
- Reduce cross-contamination between plant and construction areas
Remove Biofilm in Periodic Deep Cleaning
Because biofilms can be found in dry environments and are difficult to eradicate, it is imperative periodically deep clean and disinfect environmental surfaces and equipment. Sterilex Ultra Disinfectant Cleaner Solution 1 and Sterilex Ultra Activator Solution provide dry processing plants with a mechanism to remove biofilm and return plants to a microbial baseline.
For more information on how to control biofilms in your dry processing environment, sign up for a biofilm audit at no cost to you. This audit process helps identify what to look for and shows how to treat stubborn biofilm issues you may not be aware you have.
 Centers for Disease Control and Prevention, Cronobacter and Powdered Infant Formula Investigation. May 24, 2022
 Beuchat L, Komitopoulou E, Betts R, Beckers H, Bourdichon F, Joosten H, Fanning S, ter Kuile B. Persistence and Survival of Pathogens in Dry Foods and Dry Food Processing Environments. Report of an ILSI Europe Expert Group. November, 2011.
 Almatroudi A., Tahir S, Hu H, Chowdhury D, Gosbell IB, Jensen SO, Vickery K. Staphylococcus aureus Dry-Surface Biofilms are More Resistant to Heat Treatment Than Traditional Hydrated Biofilms. J Hosp Inf 2018; 98(2): 161-167.