Spread of a green fluorescent protein-tagged Pseudomonas putida in a water pipe following airborne contamination

Biofilms in Water Hoses of a Meat Processing Environment Harbor Complex Microbial Communities

Safe and hygienic water distribution is essential for maintaining product quality and safety. It is known that biofilms alter the appearance and microbial quality of water along the distribution chain. Yet, biofilms in water hoses throughout the food processing environment have not been investigated in detail. Here, microbial communities from water hoses and other environmental sites in contact with water, in addition to the source water itself, were studied in the meat processing environment. Biofilms were present in all water hoses as determined by the presence of bacterial DNA and biofilm matrix components (carbohydrates, extracellular DNA, and proteins). The microbial community of the biofilms was dominated by Proteobacteria, represented mainly by Comamonadaceae and Pseudoxanthomonas. Moreover, genera that are associated with an intracellular lifestyle (e.g., Neochlamydia and Legionella) were present. Overall, the microbial community of biofilms was less diverse than the water microbial community, while those from the different sample sites were distinct from each other. Indeed, only a few phyla were shared between the water hose biofilm and the source water or associated environmental samples. This study provides first insights towards understanding the microbiota of water hose biofilms in the food processing environment.

Identification of biofilm hotspots in a meat processing environment: Detection of spoilage bacteria in multi-species biofilms

Biofilms are comprised of microorganisms embedded in a self-produced matrix that normally adhere to a surface. In the food processing environment they are suggested to be a source of contamination leading to food spoilage or the transmission of food-borne pathogens. To date, research has mainly focused on the presence of (biofilm-forming) bacteria within food processing environments, without measuring the associated biofilm matrix components. Here, we assessed the presence of biofilms within a meat processing environment, processing pork, poultry and beef, by the detection of microorganisms and at least two biofilm matrix components. Sampling included 47 food contact surfaces and 61 non-food contact surfaces from eleven rooms within an Austrian meat processing plant, either during operation or after cleaning and disinfection. The 108 samples were analysed for the presence of microorganisms by cultivation and targeted quantitative real-time PCR based on 16S rRNA. Furthermore, the presence of the major matrix components carbohydrates, extracellular DNA and proteins was evaluated. Overall, we identified ten biofilm hotspots, among them seven of which were sampled during operation and three after cleaning and disinfection. Five biofilms were detected on food contact surfaces (cutters and associated equipment and a screw conveyor) and five on non-food contact surfaces (drains and water hoses) resulting in 9.3 % of the sites being classified as biofilm positive. From these biofilm positive samples, we cultivated bacteria of 29 different genera. The most prevalent bacteria belonged to the genera Brochothrix (present in 80 % of biofilms), Pseudomonas and Psychrobacter (isolated from 70 % biofilms). From each biofilm we isolated bacteria from four to twelve different genera, indicating the presence of multi-species biofilms. This work ultimately determined the presence of multi-species biofilms within the meat processing environment, thereby identifying various sources of potential contamination. Especially the identification of biofilms in water hoses and associated parts highlights the need of a frequent monitoring at these sites. The knowledge gained about the presence and composition of biofilms (i.e. chemical and microbiological) will help to prevent and reduce biofilm formation within food processing environments.

Mechanisms for floor surfaces or environmental ground contamination to cause human infection: a systematic review

Shoe soles have been shown to transfer infectious microorganisms to floor and ground surfaces. However, the possible modes of transmission of infectious agents from floors or ground surfaces to human contact for infection have not been systematically reviewed. A systematic review was performed on articles indexed in medical databases (Medline, EMBASE, PubMed) using a pre-defined search strategy and MeSH terms (date of last search: 15 March 2016). Only primary research studies in English that investigated the transmission dynamics of infectious microorganisms from floor or ground surfaces to human infection were included. Extraction of articles was performed two independent reviewers using pre-defined data fields in an Excel sheet. Disagreements were resolved by consensus. Thirty studies met the inclusion criteria. Almost all hospital-associated microorganisms including methicillin-resistant Staphylococcus aureus, Clostridium difficile, and multidrug-resistant Gram-negative species were identified on floor or ground surfaces. Several modes of transmission dynamics, most commonly direct contact or aerosolization, were identified. In conclusion, interventions such as efficient cleaning of floor surfaces and vectors that transfer infectious organisms to floors such as shoe soles could be an effective infection control strategy to prevent human disease.