A comparison of traditional and recently developed methods for monitoring surface hygiene within the food industry: an industry trial

A rapid, instrument-free, hygiene monitoring system, based on protein detection, was assessed as a means to evaluate the cleanliness of food contact surfaces within four different food processing environments. Its performance was compared to that of both ATP bioluminescence and a traditional agar-based microbiological method. Each surface was sampled using all three hygiene monitoring systems both before and after each of the production plants had carried out their normal cleaning procedures. In both cases, there was a significant difference (p < 0.05) between the number of surfaces that were passed or failed using each of the tests. In general the number of surfaces that were deemed acceptable for food production increased after cleaning but the level of agreement between test methods differed depending on the type of production facility sampled. Protein detection was most likely to fail surfaces within the baking facility, whereas ATP bioluminescence and traditional microbiology were most likely to fail surfaces within a frozen ready-meal and a cheese production unit respectively. The implications of these results are discussed in relation to plant trials of hygiene monitoring systems, the cleaning process itself, failures in disinfection, as well as the need for a combined methodological approach for monitoring cleanliness.