physiology of the microbial biofilm (Kumar and Anand 1998). Mixed species ..... Sharma M, Anand SK, Prasad DN(2003) In vitro propagation of mixed species ...
Indian J. Dairy Sci. 67(6), 2014
REVIEW ARTICLE
Biofilm - A threat to dairy industry K. V. Mogha, N. P. Shah, J. B. Prajapati, and A. R. Chaudhari
Received : July 2014 / Accepted : November 2014
Abstract
Biofilm formation in dairy industry is always noted as threat which affects the product safety and thereby resulting in food borne illness. So, it is considered as an emergent public health concern throughout the world. Biofilm formation is a dynamic process and different mechanisms are involved in its attachment, growth and colonization of microorganism on the milk contact surfaces. If these biofilms are not completely removed, they will increase the biotransfer potential. In this review, biofilm formation in the dairy, its sources, infectious disease, spoilage microorganism associated with biofilm, concern associated with biofilm and biofilm as threat to dairy industry is discussed. In addition, the conventional strategies to control or prevent these biofilm are also discussed.
perishable (e.g. butter, yoghurt and cheese) and semi perishable (milk powder, casein) milk products. To maintain the quality and safety of these products, microbiological guidelines are an essential requirement. Milk obtained from the udder of a healthy milch animal is almost in sterile condition but gets contaminated during milking, transportation, storage and processing and also due to the entry of microbes through many other sources. Insufficient sanitization and cleaning causes contaminants to accumulate in milk processing equipment which subsequently form biofilm that further become significant source of contamination of dairy products (Limsowtin and Powell, 1996). Microorganism generally get attached to the solid surfaces which is conditioned with nutrient and is sufficient for viability and growth. The microorganism aggregated on the surface gets attached, grow and multiply to form colonies of cell (Srey et al. 2013).
Keywords : Biofilm, biotransfer, food borne illness,
Study on biofilms has gained interest in the dairy/food industry because of consumer demand for higher quality products with respect to their shelf life and safety. Current trends towards lower processing runs, automation, complexity of equipment and increased awareness of the problems caused by pathogens such as Listeria monocytogenes makes biofilm a concern. It is not that this concept of biofilm attachment is new to the world but it is a burning issue to the food industries since long. Biofilm was first remarked by Antony van Leewenhoek in 1684 in a report to the Royal Society of London as vast accumulation of microorganisms in dental plaque: "The number of these animicules in the scurf of a man's teeth is so many that I believe they exceed the number of men in a kingdom". Biofilms were eventually recognized again in 1940's with the work of scientists studying marine organisms and noted their ability to attach to surfaces. In 1990, recognizing the significance of microbial activity, as well as the tremendous economic costs associated with microbial communities on surfaces, the US National Science Foundation founded the Center for Biofilm Engineering at Montana State University in Bozeman. In addition to numerous research laboratories in the US, several other groups are also studying biofilms worldwide including centers in Denmark, England, Germany, Australia,
spoilage microorganisms, conventional strategies, dairy industry
Introduction According to the changing scenario of global market, the dairy industry is considered to be one of the major food industry in world which manufactures a wide range of
K. V. Mogha, N. P. Shah ( ), J. B. Prajapati, and A. R. Chaudhari Department of Dairy Microbiology, S. M. C. College of Dairy Science, Anand 388110, Gujarat, India Department of Dairy Engineering, S. M. C. College of Dairy Science, Anand 388110, Gujarat, India N. P. Shah Department of Dairy Microbiology, Mansinhbhai Institute of Dairy and Food Technology (MIDFT), Mehsana 384002, Gujarat, India
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and Singapore. This review aims to reflect some of the basic aspects, either conceptual or empirical, which are of importance in understanding about the process of biofilm formation and more generally how it becomes a threat to dairy industry, ways by which biofilm can be prevented and the green strategy for control of them. Meyer (2003) suggested three different strategies: (i) disinfection "in time", before biofilm develops, (ii) disinfection of biofilms using harsh disinfectants, and (iii) inhibition of attachment of microbes by selecting surface materials that do not promote attachment or by supplementing with nutrients. An analysis of the different hypothesis reported in the literature shows the concern of some of the pathogenic microorganism in biofilms originated from the dairy industries. It is essential to know interfacial mechanisms involved in adhesion and multiplication of colonies. Biofilms formation - a natural process Biofilm is an aggregate of microorganisms in which cells adhere to each other on a surface. These adherent cells are frequently embedded within a self-produced matrix of extracellular polymeric substance (EPS). It is also referred as biofouling or microbial fouling which refers to the undesirable formation of a layer of living microorganisms and their decomposition products as deposits on the surfaces in contact with liquid media (Stoodley et al. 2004). Biofilm EPS is apolymeric conglomeration generally composed of extracellular DNA, proteins, and polysaccharides. Although the composition of biofilm is variable depending on the system under study, in general the major component of a biofilm is water (up to 97%). Not only bacteria and archaea, almost every species of microorganism have mechanisms by which they can adhere to surfaces and to each other. Biofilms are ubiquitous. It can be found on rocks and pebbles of most streams or rivers, surface of stagnant pools, on showers, water sewage pipes, pipeline
of the off shore oil and gas in marine engineering systems, teeth of the animal as dental plaque and surface of inside & outside plant (Schwermer et al. 2008). Biofilms and infectious diseases Biofilms have been found to be involved in a wide variety of microbial infections occurs in the human and animal body. Infectious processes in which biofilms have been implicated include common problems such as urinary tract infections, catheter infections, middle-ear infections, formation of dental plaque, gingivitis, coating contact lenses, and less common but more lethal processes such as endocarditis, infections in cystic fibrosis, and infections of permanent indwelling devices such as joint prostheses and heart valves (Rogers 2008). More recently it has been noted that bacterial biofilms may impair cutaneous wound healing and reduce topical antibacterial efficiency in healing or treating infected skin wounds. Mechanism of biofilm formation In nature microorganism get attracted to solid surface conditioned with nutrients that are sufficient for their viability and growth. Initially these microorganisms get deposited on the surface, and later get attached, grow and actively get multiplied to form colony of cells. Biofilm formation is a dynamic process and different steps are involved in their attachment and growth Conditioning of surface In dairy, organic and inorganic molecules like proteins from milk gets adsorbed to the surface forming a conditioning film. These molecules along with the microorganisms are transported to the surface by diffusion or in some cases by a turbulent flow of the liquid and gets accumulated at the solid liquid
Fig 1: Formation of biofilm
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interface of milk contact surface having a higher concentration of nutrients compared to the fluid phase. Micro topography of the milk contact surface is equally important, particularly if the surface consist of deep channels and crevices to trap bacteria.
which enlarge and coalesce to form a layer of cells covering the surface. During this time the attached cells also produce polymer (EPS) which helps in the anchorage of cells to the surface and stabilize the colony against the fluctuations of the environment (Kumar and Anand 1998). Biofilm formation
Adhesion of cells During the second stage of biofilm formation, single bacterial cells are transported to surfaces by gravity, diffusion or fluid dynamic forces from the surrounding fluid phase. The bacterial adhesion is affected by the nutrient availability in the surrounding medium and the growth stage of the bacterial cells. The adhesion of cells takes place in two stages: 1.) reversible adhesion followed by 2.) irreversible adhesion. Initial weak interaction developed between the cell wall and the substratum is referred to as reversible adhesion. Various long range interaction forces influencing the adhesion process are the van der Wall attraction forces, electrostatic forces and the hydrophobic interactions. During this stage, bacteria still show Brownian motion and can easily be removed by fluid shear forces i.e. merely by rinsing. In irreversible attachment of cells, the repulsive forces prevent the bacterial cells in making the direct contact with the surface, still the bacterial attachment is mediated by fimbriae, pili, flagella, and bacterial extracellular polymeric substances (EPSs) that act to form a bridge between bacteria and the conditioning film (Kokare et al. 2009). Spores exhibit a greater rate of adhesion than vegetative cells, these spores on adhesion to surface germinate and the vegetative cells multiply to produce EPS. In this process removal of cells requires much stronger forces such as scrubbing or scrapping. The chemical structure of the EPS varies among different types of organisms and is also dependent on environmental conditions (Momba et al. 2000). The structures that are formed depend on a large variety of intrinsic and extrinsic factors such as species, temperature, flow conditions, pH, presence of salts, nutrients, and so on (McLandsborough et al. 2006). Hamadi et al. 2014 observed that Staphylococcus aureus has the ability to adhere and to form biofilm on inert surface such as stainless steel commonly used in food industry when treated with three different types of milk (ultra high-temperature (UHT) -treated milk; UHT skimmed milk, UHT semi-skimmed milk) and reported that adhesion is maximal on the steel treated with a lower amount of fat component (skimmed milk) whereas it is minimal when it treated with a moderate amount of this component (semi skimmed milk). Formation of microcolony These irreversibly attached bacterial cells grow and divide by using the nutrients present in the conditioning film and surrounding fluid environment. This forms micro colonies
The continuous attachment of the bacterial cells to the surface and subsequent growth along with associated EPS production forms a biofilm. Multilayers of bacterial cells entrapped within the EPS containing matrices develop within the biofilm. Composition of the biofilm is heterogeneous due to the colonization of different microorganisms possessing different nutritional requirements. It does not exist as a uniform layer throughout the surface. Further increase in size of biofilms take place by the deposition or attachment of other organic and inorganic solutes and particulate matter to the biofilm from the surrounding liquid phase. The interaction of various microbial populations during the initial stages of biofilm formation has a significant effect on the structure and physiology of the microbial biofilm (Kumar and Anand 1998). Mixed species biofilms are often thicker and more stable than monospecies biofilms. It is large, complex, and organized bacterial ecosystem in which water channels are dispersed providing passages for nutrient, metabolite, and waste product exchange (Sauer et al. 2007). Buregess et al. 2014 determined the ability of different strains to form biofilm and produce spores and concluded that G. stearothermophilus strains isolated from milk powder manufacturing plant had differences in their ability to form biofilm and produce spores which also influenced the cleaning method used to control growth of thermophilic bacilli. Detachment and dispersal of biofilm As the biofilm ages, the attached bacteria, in order to survive and colonize new niches must be able to detach and disperse from the biofilm. Mainly the daughter cells are detached first from the biofilm. This would be due to various factors such as fluid dynamics and shear effects of the bulk fluid. The released bacteria may be transported to newer location and again restart the biofilm process. Biofilm detachment has been divided into 3 processes: erosion, abrasion, and sloughing (Garny et al. 2008). Erosion (result of fluid shear forces) and abrasion (collision of particles) refer to the continuous detachment of single cells or small cell clusters and affect the total biofilm surface. Sloughing refers to the instant loss of large parts of the biofilm, therefore affecting the entire biofilm and not only the biofilm surface (Morgenroth, 2003). However, the original biofilm structure, its magnitude and the detachment force might have a strong influence on the frequency and extent of a specific detachment process. Biofilms in dairy industry Milk is the best medium for the growth of microorganisms
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because of its almost neutral pH and wide variety of available nutrients. Even though milk is rich in minerals many of them may not be present in a form that can be utilized directly by bacteria. Milk contains growth stimulants such as orotic acid, which is a metabolic precursor of pyrimidines and which fosters microbial growth. Bacterial contamination can adversely affect the quality, functionality and safety of products produced by the dairy industry. When contamination of dairy products occurs evidence suggests that biofilms on the surfaces of milk processing equipment are a major source (Flint et al. 1997). Biofilms are not only a potential source of contamination, but can also increase corrosion rate, reduce heat transfer and increase fluid frictional resistance (Kumar and Anand 1998). With current trends towards longer production runs, the use of complex equipment, the automation of plants, and increasingly stringent microbiological requirements, bacterial biofilms has became a major concern to dairy manufacturers. Biofilms developed on interiors of pipes leads to clogging and corrosion especially in engineered systems. Biofilm on floors can make sanitation difficult in milk production area as they remain protected within the biofilm from the sanitizer due to EPS (Geetha and Prasad, 2011). In dairy manufacturing plants biofilms can be divided into two categories, vizbiofilms that are unique to dairy manufacturing plants which have been termed "process" biofilms e.g. those which form on surfaces (e.g. heat exchanger) in direct contact with flowing product, and biofilms which form in the general milk processing environment. In dairy environment the most commonly encountered bacteria belong to the genera Enterobacter, Listeria, Micrococcus, Streptococcus, Bacillus and Pseudomonas (Wiedmann et al. 2000; Sharma et al. 2003; Waak et al. 2002; Salo et al. 2006). Biofilm a threat to dairy industry One of the main problem the dairy industry facing is the survival of food borne pathogens or spoilage microorganisms in biofilms. Bacterial spoilage is of major concern in the dairy industry implicating both economic and public health consequences. Bacteria within biofilm are more difficult to eliminate than free living planktonic cells so, after establishment they acts as a source of recurrent contamination to plant, product and personnel. It has been shown that even with cleaning and sanitation procedures consistent with good manufacturing practices, microorganisms can remain on equipment surfaces (Geetha and Prasad 2011) and shows inhabitant resistance to antimicrobial agents (Srey et al. 2013). Teh et al. (2012) in New Zealand dairy isolated six cultures from internal surface of raw milk tanker and showed that these cultures had ability to produce single culture biofilm or co culture biofilm and cause proteolysis. Heat stable lipases causing lipolyis was due to inadequately cleaned raw milk tanker (The et al. 2013). Equipment contamination has been
reported to account for around 40% of food borne disease caused by bacteria in France (Haeghebaert et al. 2001).Some microbes naturally have a higher tendency to produce biofilms than others, but biofilms can be produced by any microbes under suitable conditions i.e on moist surfaces with some nutrients. These biofilms are dangerous because they protect one another during the application of chemical agents. This is caused by the resistance of respective microbial species against the agents used (Wirthlin et al. 2005). The et al. 2014 observed that bacteria from milk tankers forms multispecies biofilms and produce heat-stable enzymes, the free peptide concentration, which indicated proteolysis, was higher in UHT milk when exposed to multispecies biofilms than in untreated UHT milk. Bacterial biofilms create a number of serious problems for industrial fluid processing operations e.g. mechanical blockages, impedance of heat transfer processes, and biodeterioration of the components of metallic and polymeric systems which costs for billions of dollars each year. More importantly, in dairy equipment biofilms develop rapidly, many times in 8-12 h. A numbers of bacteria upto 106 per cm2 has been recorded in the regeneration section of a pasteurizer after 12 h of operation (Bremer et al. 2009). Rysstad and Kolstad (2006) showed pasteurized and extended shelf life (ESL) milk filling machine as the main source of recontamination, with the filler nozzles, aerosols, and the water at the bottom of the filling machine being of particular concern. Microorganisms originating from rinsing water especially Pseudomonas, Aeromonas, and Legionella spp. also causes contaminations of dairy products. The other possible hazards include biofilm accumulation and microbial colonization in milk pipelines, storage tanks, and milk silos (Shaheen et al. 2010), as well as fouling of heat exchangers (Flint et al. 1999). Suggestions are made that biofilm formation on the milk evaporator and consequent sloughing off into the product line is responsible for the high contamination levels of the final product (Hinton et al. 2002; Palmer et al. 2010). Other locations where biofilms often arise are ultrafiltration and reverse osmosis membranes (Tang et al. 2009a, 2009b, 2010). Membrane separation technology is often used for the removal of bacteria from skim milk in the production of extended shelf life milk, concentration of casein micelles, and recovery of serum proteins from whey. Membrane biofouling leads to decreased membrane flux and increased filtration pressure, and subsequently, increased operation cost due to frequent cleaning and replacement of clogged membranes (Liao et al. 2004; Le-Clech et al. 2006). In an ice cream plant, most of the biofilm formations were seen on the conveyer belt of the packaging machine 8 h after the beginning of the production (Gunduz and Tuncel, 2006). Heat-sensitive Pseudomonas and Listeria species are most likely to be found in pipes and silos holding milk prior to pasteurization, whereas thermophilic
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Table 1 Novel Approaches for control of biofilm Treatments Mechanical treatment with chemical agent 1. 2. 3. 4. 5. 6. 7. 8.
Air injected CIP system Cleaning of surface with short intervals Control of operating time between cleaning and sanitation Electropolishing the surface of AISI 316 SS Inclusion of germinant in CIP regime Natural disinfectant scallop shell powder slurries Peracetic acid Surface pre-conditioning with surfactants
Biological treatment with green chemicals 1. 2. 3.
Bacteriophage was engineered for expressing biofilm degrading enzyme Protease an enzyme based detergent used as biocleaners Biopreservatives such as nisin, lauricidin, reuterin and pediocin
biofilms may form in heated equipment. Brugnoni et al. (2012) demonstrated a strong and stable biofilm fornation by spoilage yeast (C.krusei) under fully turbulent flow which leads to milk quality and safety problems having significant financial losses to dairy industry. The predominant Gram-negative microorganisms limiting the shelf life of ultra heat-treated (UHT) processed fluid milk at 4°C are found to be Pseudomonas spp., especially P. fragi, P. lundensis, and P. fluorescens-like organisms (Marchand et al. 2009a; De Jonghe et al. 2011). Many of them produce heatstable extracellular lipases, proteases, and lecithinases that contribute to milk spoilage. The hydrolytic products of milk fats and proteins always decreases the organoleptic quality of fluid milk products. The persistence of accumulated microorganisms in the form of biofilms on dairy and food equipment has caused post-processing contamination, leading to lowered shelf-life of product and possible transmission of diseases (Zottola 1994). Biofilm develops on the sides of gaskets inspite of cleaning-in-place procedures. Bacteria form biofilms on the surfaces of stainless steel equipment in food processing industries, releasing bacteria that compromise the safety and quality of the final product. Novel methods for biofilm prevention and removal Cleaning procedures used in dairy manufacturing plants are limited mainly to the use of cheap chemicals (caustic, acid and chlorine) and most sanitizing regimes have remained unchanged since the early 1900's. The most significant development in cleaning was the concept of clean-in-place (CIP) systems which originated in the 1950's when manufacturing plants were smaller, processes were less complex
and the specifications were less stringent. Any modifications were usually attempts to reduce the cost of cleaning or to prevent deterioration of sensitive manufacturing plant (e.g. ultrafiltration membranes) components. Cleaning methods require reassessment to ensure the control of biofilms in dairy manufacturing plants. Ideally preventing biofilm formation would be a more logical option than treating it. However, there is presently no known effective technique that is able to successfully prevent or control the formation of unwanted biofilms without causing adverse side effects (Simo˜es et al. 2010). Table 1 enlists the novel approaches for control of biofilm. In the dairy industry the classical operations of cleaning and disinfectants are essential part of milk processing. The efficiency with which these operations are performed greatly affects the final product quality. Generally disinfectants do not penetrate the biofilm matrix left on a surface after an ineffective cleaning procedure, and thus do not destroy all the biofilm living cells. The main strategy to prevent biofilm formation is to clean and disinfect regularly before bacteria attach firmly to surfaces (Midelet & Carpentier 2004; Simo˜es et al. 2006). The chemicals currently used in disinfection processes belong to the following types: acidic compounds, aldehyde-based biocides, caustic products; chlorine, hydrogen peroxide, iodine, isothiazolinones, ozone, peracetic acid, phenolics, biguanidines, surfactants (Bremer et al. 2006; Dosti et al. 2005; Simo˜es et al. 2006). Kumari and Sarkar (2014) carried an in-vitro model study and designed an optimized procedure using 1.5% NaOH at 65ºC for 30 min -water rinse followed by -1% HNO3 at 65ºC for 10 min-water rinse for the removal of biofilm. Schlisselberg and Yaron (2013) showed that electropolishing the surface of AISI 316 SS had a lower biofilm thickness and covered with only
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23 % biofilm to that of untreated surface. Cloete and Jacobs (2001) reported that surface pre-conditioning with surfactants has potential to prevent bacterial adhesion. Nonionic and anionic surfactants were evaluated in preventing the adhesion of P. aeruginosa to stainless steel and glass surfaces. The surfactants gave more than 90% inhibition of adhesion. Mechanical treatment can also be applied with chemical agents to disinfect and remove biofilms. For instance air injected CIP system is a combination of physical and chemical processes used to remove biofilms in milking systems. Frequent system cleaning, application of combination treatments (oxidizing agents and surface-active compounds) and frequent surface monitoring are important for an effective preventive maintenance programme (Geetha and Prasad, 2011). Sharma et al. (2003) recommended controlling the operating time between cleaning and sanitation to prevent mixed species biofilm formation in pasteurization lines of commercial and experimental dairy plants. Cleaning and sanitation of foodprocessing surfaces with short intervals was proposed as an effective approach to prevent or limit sporulation in biofilms formed by vegetative B. subtilis cells (Lindsay et al. 2005). At the mature stage of the biofilm, the only ways to remove the biofilm are to increase flow rate, increase temperature, or scrub or brush. Increased temperature will loosen the biofilm layer, but excessively hot temperatures could cause other problems, such as baking the protein in the milk onto the pipe surface, giving bacteria an excellent conditioned layer for adhesion. Marques et al. (2007) showed that peracetic acid was the most efficient in removing adhered cells from the stainless steel and glass surface. Pagedar et al. (2010) stated that S.S. should be the material of choice for dairy equipments or pipeline. Knight and Craven (2010) developed a model system for evaluating the efficacy of disinfectants for inactivating bacteria present in biofilms on surfaces within dairy factory environments and concluded that the peroxyacetic acid-based product applied at 3.0% (v/v) achieved the overall reductions in counts while in some cases, disinfectants were more biocidal towards particular bacterial groups. For example, hypochlorite demonstrated a greater biocidal activity towards coliforms and staphylococci while the Quaternery ammonium compound- and acid anionic-based disinfectants demonstrated greater biocidal activity towards staphylococci. Bodur et al. (2012) studied that natural disinfectant scallop shell powder slurries could significantly reduce the numbers of L. monocytogenes, S. aureus and E. coli O157:H7 in biofilms on S.S surfaces. Pagedar and Singh (2012) studied that inclusion of germinant in CIP regime might be helpful in transformation of spores into vegetative cells, which are more susceptible to routine cleaning practices. The green strategy for biofilms control - enzymes, phages and bioregulation Besides chemical methods, biological control can be used to
eliminate biofilms (Simoes et al. 2010). Bacteriophages are studied in this regard. Bacteriophages are viruses that infect bacteria and may provide a natural, highly specific, non-toxic, feasible approach for controlling several microorganisms involved in biofilm formation. More recently, Lu and Collins (2007) engineered a bacteriophage to express a biofilm degrading enzyme that had the ability to attack the bacterial cells in the biofilm and the biofilm matrix, substantially reducing the biofilm (more than 99.9% of removal). The technology has not yet been successfully developed and relatively little information is available on the action of bacteriophages on biofilms. Augustin et al. (2004) demonstrated the potential application of enzymatic cleaning products against biofilms formed by microorganisms commonly found in dairy products. However, the performance of the enzyme action was significantly reduced in the presence of milk, particularly for proteolytic enzymes (Oulahal et al. 2003). Proteases in commercially available detergents are already been used to clean ultrafilteration units. The use of enzyme based detergents as bio-cleaners, also known as "green chemicals", can serve as a viable option to overcome the biofilm problem in the dairy industry. The specificity in the enzymes mode of action makes it a complex technique, increasing the difficulty of identifying enzymes that are effective against all the different types of biofilms. Formulations containing several different enzymes seem to be fundamental for a successful biofilm control strategy. Moreover, the use of enzymes in biofilm control is still limited due to the low prices of the chemicals. In fact, the technology and production of these enzymes and the enzyme-based detergents are mostly patent-protected. Microbial molecules, commonly used as biopreservatives, such as nisin, lauricidin, reuterin and pediocin, have been well documented for their biofilm control potential against microorganisms commonly found in dairy processing facilities, including L. monocytogenes (Garcia et al. 2008). Biofilm signaling and future perspective Finally, it deserves mention that much research and many new developments are currently ongoing in the field of biofilms disinfection, including the development of molecule that interfere quorum sensing (Girennavar et al. 2008, Pan and Ren 2009) In bacteria, cell-to-cell communication is a wide spread phenomenon controlling a broad range of activities and it depends on the production, secretion, and response to small, diffusible signal molecules called autoinducers. The signal molecules are produced and secreted at a basal level during bacterial growth. Bacteria use signaling molecules for inter- and intracellular communication. This phenomenon of bacterial cell-to-cell communication is known as quorum sensing. Quorum-sensing signals are implicated in bacterial pathogenicity and food spoilage. Therefore, blocking
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the quorum-sensing signaling molecules in food-related bacteria may possibly prevent quorum-sensing-regulated phenotypes responsible for food spoilage. Quorum-sensing inhibitors/antagonists could be used as food preservatives to enhance the shelf life and also increase food safety. Biofilms are real threat to dairy and food processing industries as they can cause safety issues leading to economical and brand image consequences. Eventhough several approaches has been tried for prevention and control of biofilms, there is a need to look for innovative approaches. One of the approach could be coating of equipment that can reduce the microbial attachment. It is also possible to design cleaners and sanitizers with enhanced applications for e.g. fortification with EPS or protein degrading enzyme inhibiting quorum sensing signal at different stages of biofilm formation can also give a possible solution for minimizing biofilm formation. Biofilm formation can be used for beneficial effects. The gastrointestinal tract are colonized by lactic acid bacteria and Bifidobacetriaspp which constitutes a major part of the natural microflora and serve as a protective layer against the colonization of pathogenic bacteria. These organisms maintain equilibrium between the beneficial and potential harmful microflora in the gut and also promotes a probiotic effect when consumed through various fermented food.
Conclusions Bacterial biofilms are omnipresent in nature, and the dairy industry does not escape from the problems they can cause. In particular, biofilms formed on milk-processing equipment and other food contact surfaces act as a persistent source of contamination threatening the microbiological quality and safety of milk products, and may result in food-borne disease and economic losses. Some of the approaches which can be used for prevention and control of biolfilm are modification in existing CIP programmes, Use modified detergents and sanitizer, give special attention to biofilm prone areas in processing line and probably best option is to use green chemicals to reduce the environmental problems.
References Augustin M, Ali-Vehmas T, Atroshi F (2004) Assessment of enzymatic cleaning agents and disinfectants against bacterial biofilms. J Pharm Pharm Sci 18:55-64 Bodur T, Mehmetoglu AC (2012) Removal of Listeria monocytogenes, Staphylococcus aureus and Escherichia coli O157:H7 biofilms on stainless steel using scallop shell powder. Food Control 25:1-9 Bremer PJ, Fillery S, McQuillan AJ (2006) Laboratory scale clean-in-place (CIP) studies on the effectiveness of different caustic and acid wash steps on the removal of dairy biofilms. Int J Food Microbiol 106:254262. Brugnoni LI, Cubitto MA, Lozano JE (2012) Candida krusei development on turbulent flow regimes: Biofilm formation and efficiency of cleaning and disinfection program. J Food Eng 111:546-552
Burgess SA, Flint SH, Lindsay D (2014) Characterization of thermophilic bacilli from milk powder plant. J Appl Microbiol 116(2):350-359 Cloete T E, Jacobs L (2001) Surfactants and the attachment of Pseudomonas aeruginosato 3CR12 stainless steel and glass. Water SA 27:21-26 De Jonghe V, Coorevits A, Van Hoorde K, Messens W, Van Landschoot A, De Vos P, Heyndrickx M (2011) Influence of storage conditions on the growth of Pseudomonas species in refrigerated raw milk. Appl Environ Microbiol 77:460-70 Dosti B, Guzel-Seydim Z, Greene AK (2005) Effectiveness of ozone, heat and chlorine for destroying common food spoilage bacteria in synthetic media and biofilms. Int J Dairy Technol 58:19-24 Flint S, Brooks JD, Elzen HV, Bremer PJ (1997) Biofilms in dairy manufacturing plant - a threat to product quality. Food Technol 27:6164. Flint SH, Elzen HV, Brooks JD, Bremer PJ (1999) Removal and inactivation of thermo-resistant streptococci colonizing stainless steel. Int Dairy J 9:429-36. Garcia ABE, Cann IKO, Martin SE, Guerrero LI, Regalado C (2008) Effect of Lactococcus lactis UQ2 and its bacteriocin on Listeria monocytogenes biofilms. Food Control 19:670-680. Garny K, Horn H, Neu TR (2008) Interaction between biofilm development, structure and detachment in rotating annular reactors. Bioprocess Biosyst Eng 31:619-29 Geetha R, Prasad V(2011) Recent Advances in Controlling Bacterial Biofilms in Dairy Industry-A Review. Indian J Dairy Sci 64:267-277 Girennavar B, Cepeda ML, Soni KA, Vikram A, Jesudhasan P, Jayayprakasha GK, Pillai SD, Patil BS (2008) Grapefruit juice and its furocoumarins inhibits autoinducer signaling and biofilm formation in bacteria. Int J Food Microbiol 125:204-208 Gunduz GT, Tuncel G (2006) Biofilm formation in an ice cream plant. Antonie Van Leeuwenhoek Intl J Gen MolMicrobiol 89:329-36 Haegheaert S, LeQuerree F, Vaillant V, Delarocque AE, Bouvet P (2001) Less toxiinfections alimentaires collectives en France en 1998. Bull Epidemiol Hebdomadaire 15 Hamadi F, Asserne S, Bensouda S, Mabrounki M, Latrache H (2014) Adhesion of Staphylococcus aureus on stainless steel treated with three types of milk. Food Control 38:104-108 Hinton AR, Trinh KT, Brooks JD, Manderson GJ (2002) Thermophile survival in milk fouling and on stainless steel during cleaning. Food Bioproducts Process 80:299-304 Knight GC, Craven HM (2010). A model system for evaluating surface disinfection in dairy factory environments. Int J Food Microbiol 137:161-167 Kokare CR, Chakraborty S, Khopade AN, Mahadik KR (2009) Biofilm: importance and applications. Indian J Biotechnol 8:159-68 Kumar CG, Anand SK (1998) Significance of microbial biofilms in food industry: a review. Int J Food Microbiol 42:9-27 Kumari S, Sarkar PK(2014) In vitro model study for biofilm formation by Bacillus cereus in dairy chilling tanks and optimization of clean-inplace (CIP) regimes using response surface methodology. Food Control 36:153-158 Le-Clech P, Chen V, Fane TAG (2006) Fouling in membrane bioreactors used in wastewater treatment. J Membr Sci 284:17-53 Liao BQ, Bagley DM, Kraemer HE, Leppard GG, Liss SN(2004) A review of biofouling and its control in membrane separation bioreactors. Water Environ Res 76:425-36 Limsowtin GKY, Powell IB(1996) Milk quality for cheese making. Aust J Dairy Technol 51:98-100 Lindsay D, Brozel VS, Von Holy A(2005) Spore formation in Bacillus subtilis biofilms. J Food Prot 68:860-865 Lu TK, Collins JJ (2007) Dispersing biofilms with engineered enzymatic bacteriophage. Proceedings of the National Academy of Sciences USA 104:11197-11202 Marchand S, Heylen K, Messens W, Coudijzer K, De Vos P, Dewetinck K, Herman, L, De Block J, and Heyndrickx M (2009) Seasonal influence on heat-resistant proteolytic capacity of P.lundensis and P. fragi, predominant milk spoilers isolated from Belgian raw milk samples.
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Environ Microbiol 11:467-82 Marques SC, Rezende JD, Alves LA, Silva BS, Alves E, Abreu LR, Piccoli RH (2007) Formation of biofilms by Staphylococcus aureuson stainless steel and glass surfaces and its resistance to some selected chemical sanitizers. Braz J Microbiol 38:2-14 McLandsborough L, Rodriguez A, Perez-Conesa D, Weiss J (2006) Biofilms: at the interface between biophysics and microbiology. Food Biophys 1: 94-114 Meyer B (2003) Approaches to prevention, removal and killing of biofilms. International Biodeterioration & Biodegradation 51(4):249-253 Midelet G, Carpentier B (2004) Impact of cleaning and disinfection agents on biofilm structure and on microbial transfer to a solid model food. J Appl Microbiol 97:262-270 Momba MNB, Kfir R, Venter SN, Cloete TE (2000) An overview of biofilm formation in distribution systems and its impact on the deterioration of water quality. Water San 26:59-66 Morgenroth E (2003) Detachment: an often overlooked phenomenon in biofilm research and modeling. In: Bishop B, Wuertz S, Wilderer P, editors. Biofilms in wastewater treatment, an interdisciplinary approach. London, UK: IWA Publishing House 264-293 Oulahal-Lagsir N, Martial-Gros A, Bonneau M, Blum LJ (2003) Escherichia coli-milk biofilm removal from stainless steel surfaces: synergism between ultrasonic waves and enzymes. Biofouling 19:159-168 Pagedar A, Singh J (2012) Influence of physiological cell stages on biofilm formation by Bacillus cereus of dairy origin, Int Dairy J 23:30-35 Pagedar A, Singh J, Batish VK (2010) Surface hydrophobicity, nutritional contents affect, Staphylococcus aureus biofilms and temperature influences its survival in preformed biofilms, J Basic Microbiol 50:98106 Palmer J S, Flint SH, Schmid, J, Brooks JD (2010) The role of surface charge and hydrophobicity in the attachment of Anoxybacillus flavithermus isolated from milk powder. J Ind Microbiol Biotechnol 37:1111-9 Pan J, Ren D (2009) Quorum sensing inhibitors: a patent overview. Expert Opin Ther Pat 19:1581-1601 Rogers AH (2008) Molecular Oral Microbiology.Caister Academic Press 65-108 Rysstad G, Kolstad J. (2006) Extended shelf life milk-advances in technology. Intl J Dairy Technol 59:85-96 Salo S, Ehavald H, Raaska L, Vokk R, Wirtanen G(2006) Microbial survveys in Estonian dairies. LWT Food Sci and Tech 39:460-471 Sauer K, Rickard AH, Davies DG (2007) Biofilms and bio complexity. Microbe 2:347-55 Schlisselberg DB, Yaron S. (2013)The effects of stainless steel finish on Salmonella Typhimurium attachment, biofilm formation and sensitivity to chlorine. Food Microbiol 35:65-72 Schwermer CU, Lavik G, Abed RM(2008) Impact of nitrate on the structure and function of bacterial biofilm communities in pipelines used for injection of seawater into oil fields. Appl Environ Microbiol 74:284151
Shaheen R, Svensson B, Andersson MA, Christiansson A, Salkinoja-Salonen M (2010) Persistence strategies of Bacillus cereus spores isolated from dairy silo tanks. Food Microbiol 27:347-55 Sharma M, Anand SK, Prasad DN(2003) In vitro propagation of mixed species biofilms using online consortia for dairy processing lines. Milchwissenschaft 58:270-273 Simo˜es M, Simo˜es LC, Machado I, Pereira MO, Vieira MJ (2006) Control of flow-generated biofilms using surfactants - evidence of resistance and recovery.Food and Bioproducts Processing 8:338-345 Simo˜es M, Simo˜es LC, Maria JV (2010) A review of current and emergent biofilm control strategies.Food Sci Technol 43:573-583 Srey S., Jahid IK, Ha SD (2013) Biofilm formation in food industries: A food safety concern. Food control 31:572-585 Stoodley HL, Costerton JW, Stoodley P (2004) Bacterial biofilms: from the natural environment to infectious diseases. Nature Rev Microbiol 2:95-108 Tang XM, Flint SH, Bennett RJ, Brooks JD (2010) The efficacy of different cleaners and sanitisers in cleaning biofilms on UF membranes used in the dairy industry. J Membr Sci 352:71-5 Tang XM, Flint SH, Bennett RJ, Brooks JD, Morton RH (2009b) Biofilm growth of individual and dual strains of Klebsiellaoxytoca from the dairy industry on ultrafiltration membranes. J Ind Microbiol Biotechnol 36:1491-7 Tang XM, Flint SH, Brooks JD, Bennett RJ (2009a) Factors affecting the attachment of micro-organisms isolated from ultrafiltration and reverse osmosis membranes in dairy processing plants. J Appl Microbiol 107:44351 Teh KH, Flint S, Palmer J, Andrews P, Bremer P, Lindsay D (2012) Proteolysis produced within biofilms of bacterial isolates from raw milk tankers. Int J Food Microbiol 157:28-34 Teh KH, Lindsay D, Palmer J, Andrews P, Bremer P, Flint S (2013) Lipolysis within single culture and co-culture biofilms of dairy origin. Int J Food Microbiol 163:129-135. The KH, Lindsay D, Palmer J, Andrews P, Bremer P, Flint S (2014) Proteolysis in ultra-heat-treated skim milk after exposure to multispecies biofilms under conditions modelling a milk tanker. Inte J Dairy Technol 67(2):176-181 Waak E, Tham W, Danielsson TML (2002) Prevalence and fingerprinting of Listeria monocytogenes strains isolated from raw whole milk in farm tanks and in dairy plant receiving tanks. App Environ Microbiol 68:2085-2095 Wiedmann M, Weilmeier D, Dineen SS, Ralyea R, Boor KJ (2000) Molecular and Phenotypic characterization of Pseudomonas spp. Isolated from milk. Appl Environ Microbiol 66:2085-2095 Wirthlin MR, Chen PK, Hoover CI (2005) A laboratory model biofilm fermenter:design and intial trial on a single species biofilm. J. Periodontol 1443-1449 Zottola EA (1994) Microbial attachment and biofilm formation: a new problem for the food industry. Food Technol 48:107-114.
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