The Role of Manual Cleaning in Biofilm Prevention and Removal Biofilms are a serious food safety threat because they are capable of harboring pathogens and forming on many types of surfaces found throughout food manufacturing facilities. Biofilms also protect pathogens from chemicals and environmental stresses, allowing these microorganisms to survive for longer periods of time and to spread at unpredictable rates. Because of these factors, having an effective strategy to prevent and remove biofilms requires appropriate cleaning tools and methods. Understanding Biofilms in the Food Industry According to the CDC, each year 48 million people get sick from a foodborne illness, 128,000 are hospitalized, and about 3,000 die in the United States. Listeria monocytogenes, Salmonella, Shiga-toxin producing E. coli, Campylobacter jejuni, and Staphylococcus aureus are among the key causative agents behind those illnesses and deaths. The principal of these, Listeria monocytogenes and Salmonella , are responsible for over 40% of major FDA food recalls. Although the microbial composition of a biofilm will vary, dependent on the environmental conditions, the most common pathogens listed above are all known to create and thrive in biofilms. Some biofilms are relatively simple and others more complex, but they are all composed of three basic elements – microorganisms, nutrients, and water. When these three elements are left undisturbed over time, the microorganisms secrete an extracellular polymeric substance (EPS), or “slime”, that is composed of polysaccharides, nucleic acids, and glycoproteins. This slime coating helps protect microbes from chemicals and environmental stresses and further anchors the microbes to the surface. Microbes in a biofilm can be up to 3,000 times more resistant to disinfectants than ‘free floating’ cells and they are able to survive with limited nutrients, moisture, and oxygen, and in adverse pH conditions. The biofilm enables the microbial community to survive, colonize, and spread to contaminate other surfaces and food products via air, moisture, human contact, and other vectors. Research on biofilms is still ongoing, and it has been found that microorganisms are able to communicate with each other to group themselves, share resources, and offer cross-protection through a molecular signaling technique called “quorum-sensing.” These are the typical steps of biofilm formation: Note: The best time to control biofilms is prior to step 3. After this, the mature biofilms are much more difficult to remove because of their protective exopolymer matrix. 6 Biofilm formation cycle repeats 1 "Free-floating" bacteria settle on surface 2 Bacteria clump together and attach on surface 3 Bacterial cells grow and divide to form biofilms 4 Mature biofilm forms 5 Portion of biofilm disperses to release "free-floating" cells to other areas 2
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