A brief overview
Biofilms are an umbrella protection of one or more types of microorganism communities that are enclosed together by a matrix-bound of extracellular polymeric substances (EPS). This attachment of microorganisms to any contact surface of food processing plants or biological surfaces. Biofilms comprise a community in the race for survival, physiological cooperation, and energy flow with each other, and they form a microenvironment to resist any kind of hostile environment. Bacterial communities in biofilms may contain both harmless microorganisms and dangerous pathogenic bacteria that pose a threat to the food industry. Van Leeuwenhoek was the first to discover biofilms on the tooth surface, implying that the survival strategy is universal in nature. Biofilms related to some diseases include dental caries, gingivitis, and cystic fibrosis. Biofilms threaten food processing industries in various ways; they can contaminate and cause acute foodborne illness, leading to rising product recalls. We discussed biofilm’s challenges for the food industry.
How do biofilms form?
In general, bacteria are considered free-living cells, which is called a planktonic lifestyle, and they slowly develop biofilms over time through five different steps as
- Initial attachment to abiotic (food processing instruments, containers, water tap) or biotic (surfaces) surfaces at first.
- Irreversible attachment is achieved using EPS components and the cell adhesion surface pili of bacteria.
- Maturation I; this process is repeated several times to form a layer of cells or a small cluster.
- Maturation II; clusters develop into biofilm maturation, and several cells become detached to form networks or cavities. Final steps as
- Biofilm dispersion: microorganisms communicate to release or eruption and migrate to a new surface due to biofilm resource exhaustion.
Why are biofilms difficult to eliminate from the surface?
Extracellular polymeric substance (EPS), a complex biomolecule that general sanitizers cannot penetrate and is composed of proteins, lipids, and extracellular DNA, functions as a protective layer. Antimicrobial agents are also less effective due to the 1,000-fold increase in antibiotic resistance in biofilm. Hence Biofilms act as an umbrella of protection for microorganisms. The biofilm can still regenerate even if just one is left after the surface skins out of the biofilm section.
Biofilms are the threatening to food industries
In the present scenario, biofilms can’t overestimate their capability of outbreak, and their eruption is independent of any circumstances in food processing industries. Biofilms have been reported as a cause of foodborne illness outbreaks on multiple occasions, and according to food safety data, biofilms are responsible for 60% of foodborne illness outbreaks.
Biofilms can cause significant economic losses in the food processing industry by causing corrosion and biofouling on surfaces, necessitating the replacement of costly spare parts of food processing units and even the need to recall products. In addition, it alters the food products’ quality and modifies the organoleptic characters due to the secretion of lipases or proteases, which makes them unsatisfying to consumers. However, when foodborne disease outbreaks occur, the situation worsens because they cause direct harm to consumers and eventually drag food industries and their quality systems into court trials or criminal prosecution, resulting in massive capital losses for brands as well.
Food production facilities encounter a cluster of a specific strain of pathogenic microorganisms, either alone or in combination, such as Listeria spp., Bacillus cereus, Salmonella spp., Staphylococcus aureus and Escherichia coli. Some scientists claim that the E. Coli O157:H7 strain has a strong capacity to form biofilm on food processing surfaces, which has a potent risk factor to causing foodborne illness in consumers. Thus, the infrastructure of food processing industries is quite susceptible to a diverse range of microorganisms that initiate biofilm formation on food matrixes or production units.
How to detect and control biofilm in food and allied industries
There are a number of methods used to detect the biofilm formation on the surface of the food processing unit, including microscopy for biofilm morphology, scanning electron microscopy (SEM), and atomic force microscopy (AFM). A staining technique used for the study of biofilms is called fluorescent in situ hybridization (FISH). Quorum sensing is an intercellular signalling molecule that can be used for the detection of biofilms. Examples of quorum sensing molecules include oligopeptides, N-acyl homoserine lactones (AHLs), and autoinducer-2 (AI-2).
However, other methods like Tissue Culture Plate (TCP), bioluminescent assay, Tube Method (TM), Congo Red Agar Method (CRA), and piezoelectric sensors can also help to detect biofilm production. There are several commercial Biofilm Monitoring Audit services and laboratory testing facilities available to food allied industries to mitigate the risk of foodborne disease.
For the control of biofilm, there are several monitoring methods that can be employed to control the biofilm formation on the surface of the food processing unit. PCR amplification technique can be used for detecting of viable but nonculturable (VBNC) microorganism as example Listeria monocytogenes enter the formation of biofilm. Food manufacturing units should perform periodical swab testing.
There are several physical methods, like hot steam flow, dry-ice cleaning, UV radiation, ultrasonication, radiation, and plasma, used for cleaning and disinfection of food processing units to maintain hygiene and food safety. There are several sanitizers or chemicals used to minimise or destroy biofilm formation in food manufacturing units, such as sodium hypochlorite, sodium hydroxide solutions, hydrogen peroxide, peracetic acid, Ozone, Quaternary ammonium compounds (Metaquats).
Moreover, biofilm can also be treated with effective monitoring or damage with the enzymatic action of industrial detergent, which is collectively comprised of amylases, cellulases, lyases, glycosidases, DNAses. Now these days, antibacterial and antibiofilm steel coating agents are used in food processing units; recently, nanoparticle coating agents such as silver, gold, and metal oxides have been used. Another most effective method for eradicating biofilm is using Quorum Sensing Inhibition agents
How can cultivator Phyto Lab help you?
Cultivator Phyto Lab is a state-of-the-art testing laboratory equipped with cutting edge technologies and providing advance microbiological testing analysis of your brand products. Generally speaking, the food industries policy should be adhered to consistently monitoring the entire infrastructure of the food manufacturing unit with environmental swab testing analysis for monitoring of different microorganisms. Hazard Analysis Critical Control Points (HACCP), with cultivator Phyto lab serving as your destination to assess the quality of your food product.
Author : Dr. Sanjoy Gupta and Bhaskar Ashish