P19 | Microbial contamination of food business surfaces: 3 years of self-monitoring data

Purpose. Food safety is one of the main priorities for businesses in the sector, as consumer well-being depends on the quality and hygiene of the products. The aim of our work was to verify a fundamental aspect: the monitoring of work surfaces, which are potential vehicles for pathogenic microorganisms. The focus was essentially on surfaces in direct contact with food, such as work surfaces or equipment, e.g., slicers, knives, etc. This study evaluated the bacterial load detected on various surfaces within the checks carried out by food business self-control systems, including surfaces exposed to public contact, such as cups or display cases, to assess the impact of service activities on microbiological contamination. Methods. The study was conducted by analyzing a total of 1724 surface swabs taken in self-monitoring at various food businesses over a 3-year period from 2022-2024. Sterile swabs immersed in a test tube containing sterile diluent or neutralizing fluid were used, according to the sampling methods specified in ISO18593:2018. The samples, analyzed within 24 hours, were inoculated by immersion in Plate Count Agar and incubated at 30°C for 72 hours, as described in ISO 4833-1:2022. The results were expressed in CFU/cm2 of sampled surface or, for some types of sampling, in CFU/swab. Results. Graph 1 presents the results of the bacterial load detected, broken down by surface type, compared to the swabs examined. The data show that, in the food businesses studied, the highest microbial contamination was found on display cases (17.72%) and operators' hands (15.07%). On the contrary, the slicer (2.22%) and the refrigerators (3.70%) are the least contaminated surfaces. Conclusions. Regarding the different types of surfaces sampled, see graph 2, it is evident that within the context of self-monitoring, the most frequently monitored surface by operators was the workbench, likely due to its direct exposure to food preparation and handling. However, if we correlate the contamination data with the sampling frequencies, it becomes clear that the real critical issue seems to be attributable to the operators' hands: Few samples but many positives. Finally, analyzing the trend of the checks carried out over the three-year period, graph 2, we observe decidedly low and fairly constant values in the percentage of samples where bacteria were detected, suggesting that the cleaning and disinfection practices adopted by companies are ultimately quite adequate and effective.