Identification and spoilage potential of the remaining dominant microbiota on food contact surfaces after cleaning and disinfection in different food industries

After cleaning and disinfection (C&D), surface contamination in the production environment of food companies can still be present. Microbiological contamination on cleaned surfaces can be transferred to the manufactured food and consequently lead to foodborne illness and early food spoilage. However, knowledge about the microbiological composition of this residual contamination after C&D and the importance in food spoilage in different food sectors is lacking. In this study, we therefore aimed to identify the remaining dominant microbiota on food contact surfaces in seven food companies after C&D and assessed the spoilage potential of the microbiota under lab conditions. The dominant microbiota on surfaces that were still contaminated with 10² CFU/100cm² or more after C&D in seven food companies was identified based on the 16S rRNA sequence. In addition, the potential to hydrolyze proteins, lipids and phospholipids, fermentation of glucose and lactose, production of hydrogen sulphide and the degradation of starch and gelatin was evaluated. Genera that were most abundant among the dominant microbiota on food contact surfaces after C&D were Pseudomonas, Microbacterium, Stenotrophomonas, Staphylococcus and Streptococcus. Pseudomonas spp. were identified in five of the participating food companies and 86.8% of these evaluated isolates showed spoilage potential in the laboratory tests. Microbacterium and Stenotrophomonas spp. were identified in five or six of the food companies, respectively and all these tested isolates had spoilage potential. This new information is useful for the concerned food industries in their quest to characterize surface contamination after C&D, to identify causes of microbiological food contamination and spoilage and to determine the possible need for a more thorough C&D.