Effect of food residues on efficiency of surfactant disinfectants against food related pathogens adhered on polystyrene and ceramic surfaces

The adhesion of pathogenic bacteria on food contact surfaces increases the risk of cross-contamination in the food industry. However, food-borne disease introduced by the production process can be mitigated by surfactant use. This study investigates the effect of food residues (milk, beef gravy and tuna gravy) on the bactericidal efficiency of benzalkonium chloride (BAC) and alkyldiaminoethylglycine hydrochloride (AGH). The test was conducted on pathogenic bacteria (Escherichia coli O26, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus cereus, and B. cereus spores) dried and adhered to the surfaces of polystyrene and ceramic dishes at room temperature for 1.5 h. The protein and lipid rich food residues protected the bacterial cells from dehydration and from the adverse effects of disinfectants, although bacterial numbers were decreased after drying and the surfaces were clearly sterilized after disinfectant treatment at typical concentrations (0.5 mg/ml-2.0 mg/ml) for 10 min. Following general and proper washing processes, the bactericidal effect of the disinfectants became clearly visible. These results indicate that applying a proper washing process prior to disinfectant treatment can prevent cross-contamination.