Staphylococcus aureus: biofilm nell'industria lattiero-casearia

Coagulase positive Staphylococcus aureus is a pathogenic microorganism. It can contaminate dairy environments and form biofilms. These structures are one of the biggest problem in industry because they may cause contamination and economic damage. Biofilms are defined as a sessile microbial community, characterized by adhesion to inert surfaces and production of eso-polysaccharide matrix. Formation of biofilms comprehend several stages, during the first stage is fundamental the presence of conditioning film, a layer of organic material. In dairy environments several factors can influences bacterial adhesion. The conditioning film consists of milk residues like protein and surfactant. Its composition can variate with thermic treatment of the milk, for example proteins can be denatured. Also milk fats influence bacterial adhesion, the increase in the percentage of fats seem to reduce the adhesion, by altering physic-chemical properties of surfaces. Proteins content of milk also may impair the adhesion, in particular β-casein concentration; on the other hand, Ionic potential seem to enhance adhesion and therefore biofilm formation. Moreover, biofilms are resistant to common detergents and sanitizers, except for benzalkonium chloride. To address this issue, biofilm research developed several techniques like ultrasound, use of electrolyzed water and essential oil. It is established that biofilms are source of economic losses and food poisoning. To reduce these damages attention of food operators is fundamental, moreover research must continue to deduced new techniques for prevention and fight against biofilms formation.