Adhesion of Staphylococcus aureus on stainless steel treated with three types of milk

•Staphylococcus aureus can cause food poisoning.•S. aureus have the ability to adhere to stainless steel used in food processing equipment.•Stainless steel physicochemical properties were modified after treatment with three types of milk.•Fat component of milk changes the stainless steel properties and reduces bacterial adhesion.

Staphylococcus aureus has the ability to adhere and to form biofilm on inert surface such as stainless steel commonly used in food industry. The biofilm formed on the surface of milk processing equipments could be a source of dairy products contamination. This contamination causes a food poisoning. In this paper the S. aureus adhesion on stainless steel treated by three types of milk (ultrahigh-temperature (UHT)-treated milk; UHT skimmed milk, UHT semi-skimmed milk) was investigated.Stainless steel was exposed to three types of milk with a different amount of fat component. Contact angles measurements were used to determine the surface physicochemical properties of substratum treated with the three milk products. The hydrophobicity and electron acceptor properties of stainless steel seem to be decreasing with the amount of fat component present in milk but its electron donor property increase with this component. The ability of S. aureus to adhere to stainless steel treated and untreated with milk was also examined. Treatment with the three types of milk reduces bacterial attachment. On treated substratum, the adhesion extent was affected by the type of milk and consequently by the amount of fat component. The lower and the higher adhesion were obtained when the steel was treated by the UHT semi-skimmed milk and UHT skimmed milk respectively. The correlation between physicochemical properties and S. aureus adhesion show that this latter was controlled by hydrophobicity and electron donor properties.The findings of this work can contribute to develop strategies for prevent S. aureus adhesion on stainless steel and biofilm formation. Also they could be taken into account in cleaning and disinfection procedures.