Assessment of Antimicrobial Activity in Different Sanitizer Products Commonly Used in Food Processing Environment and Home Setting

The presence of microorganisms to work surfaces represents a potential risk to transmit pathogens to food or humans by cross-contaminations. In food processing and in home setting, disinfectants or sanitizer products are used on inanimate objects and surfaces to inactivate all recognized pathogenic microorganisms. Uncorrected disinfection procedures, in term of declared concentration or time of contact, can lead to the survival of different types of microorganisms. In this study, six sanitizers (herein named A, B, C, D, E, F) belonging to different class of chemical disinfectants were considered: acids (products A, E), halogens (B), quaternary ammonium compounds (C), oxidizing agents (F), mixed classes (D). The antimicrobial activity of each sanitizer was evaluated against Escherichia coli O157:H7 ATCC 35150, Staphylococcus aureus ATCC 43387, Pseudomonas aeruginosa ATCC 9027, Enterococcus faecalis ATCC 29212 and Candida albicans ATCC 14053 was examined by the quantitative suspension test indicated by EN 1276. Our investigation confirmed that different factors affect the activity of chemical sanitizers such as formulation, temperature, time of contact, target microorganism, organic load. The last factor is taken in consideration in the suspension test indicated by EN 1276, that required performing experiments in both dirty and clear simulated conditions. Our data showed that, in general, the examined sanitizers are effective in reducing bacterial growth (logarithmic reduction >5) at the manufacturer recommended concentrations or lower, but in some cases the presence of organic matter interfered with their activity. In this case, it was necessary to use a more high concentration of the chemical product, as reported for the products A, B and F. In conclusion, this work highlighted the need that, in each sanitizer product label, the exact information regarding concentration and time of contact are better specified to obtain the indicated bactericidal effect and avoid the onset of bacterial resistance. Moreover, it’s important that disinfectants are applied on work surfaces after cleaning and removing organic matter that could create a physical barrier protecting microorganisms from the activity of the sanitizers.