Microorganisms can colonize and subsequently form biofilms on surfaces, which protect them from adverse conditions and make them more resistant than their planktonic free-living counterparts. This is a major concern in the food industry because the presence of biofilms has significant implications for microbial food contamination and, therefore, for the transmission of foodborne diseases. Adequate hygienic conditions and various preventive and control strategies have consequently been developed to ensure the provision of safe, good-quality food with an acceptable shelflife. This review focuses on the significance of biofilms in the food industry by describing the factors that favor their formation. The interconnected process among bacteria known as "quorum sensing," which plays a significant role in biofilm development, is also described. Furthermore, we discuss recent strategic methods to detect, quantify, and remove biofilms formed by pathogenic bacteria associated with food processing environments, focusing on the complexity of these microbial communities.

Food contact surfaces are primary sources of bacterial contamination in food industry processes. With the objective of preventing bacterial adhesion and biofilm formation on surfaces, this study evaluated the antimicrobial activity of silver (Ag-NPs) and zinc oxide (ZnO-NPs) nanoparticle-containing polyester surfaces (concentration range from 400 ppm to 850 ppm) using two kinds of bacteria, Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli), and the prevention of bacterial biofilm formation using the pathogen Listeria monocytogenes. The results of antimicrobial efficacy (reductions ≥ 2 log CFU/cm 2 ) showed that at a concentration of 850 ppm, ZnO-NPs were effective against only E. coli (2.07 log CFU/cm 2 ). However, a concentration of 400 ppm of Ag-NPs was effective against E. coli (4.90 log CFU/cm 2 ) and S. aureus (3.84 log CFU/cm 2 ). Furthermore, a combined concentration of 850 ppm Ag-NPs and 400 ppm ZnO-NPs showed high antimicrobial efficacy against E. coli (5.80 log CFU/cm 2 ) and S. aureus (4.11 log CFU/cm 2 ). The results also showed a high correlation between concentration levels and the bacterial activity of Ag-ZnO-NPs (R 2 = 0.97 for S. aureus, and R 2 = 0.99 for E. coli). They also showed that unlike individual action, the joint action of Ag-NPs and ZnO-NPs has high antimicrobial efficacy for both types of microorganisms. Moreover, Ag-NPs prevent the biofilm formation of L. monocytogenes in humid conditions of growth at concentrations of 500 ppm. Additional studies under different conditions are needed to test the durability of nanoparticle containing polyester surfaces with antimicrobial properties to optimize their use.Foods 2020, 9, 442 2 of 15 studies include the development of antimicrobial surfaces capable of preventing and/or inhibiting bacterial adhesion [8][9][10][11].Metal agents such as silver, copper, zinc, titanium, and cobalt have antimicrobial properties. When these agents remain on surfaces, their biocidal properties are gradually released onto the surface through a process of ion exchange, providing continuous, lasting antimicrobial activity [12][13][14]. The biocidal properties of metal agents depend on the characteristics of their nanoparticles, such as size, distribution, morphology, and the release of very small quantities of their cations on the substrates on which they are acting [15,16]. The antimicrobial activity of these agents is also affected by extrinsic factors, such as the pH of the medium, time of exposure, concentration, UV radiation, and the presence of other substances or microorganisms [17][18][19].Two of the most extended nanocomposites for antibacterial purposes are silver and zinc oxides embedded in polymeric matrices [20][21][22]. The antimicrobial activity of silver (Ag) and zinc (Zn) repels or inhibits the initial attachment of bacteria by either exhibiting an anti-biofouling effect or by inactivating cells in contact with surfaces, causing their death [23,24]. Additionally, the antibacterial properties of these agents reduce the risk o...

Bacterial biofilms are highly difficult to control, hence significant economic resources have been allocated to develop strategies to eradicate them. This study evaluated the effect of an enzymatic treatment to be used as a cleaning product to control the presence of biofilms. Two different materials used in the food industry, polystyrene and stainless steel, were tested using Salmonella Typhimuirum and Cronobacter sakazakii. Biofilm formation was carried out by inoculating the surfaces with a standardized concentration of 4 log (CFU cm−2) and incubated for 48 hr with renewal of nutrients. The biofilm formation and subsequent enzymatic treatment were quantified using fluorescence microscopy and the conventional culture method. The enzymatic treatment showed significant reductions of 2–3 log (CFU cm−2) in biofilm cells, which was attributed to the degradation of the extracellular matrix and the further detachment of both microorganisms. The maximum biofilm detachment obtained with the preventive formula was 46.67%; however, this percentage could be increased by applying an aggressive treatment or by adding a subsequent disinfection step that would eliminate adhered microbial cells. Further, the enzymatic cleaning treatment could be exploited as a potent technology to control bacterial adherence and biofilm formation in the food industry.