The microbiome of water and water-associated biofilms in meat processing facilities

Drinking water represents a reservoir for microorganisms. Microorganisms from water are able to attach to the inner surface of a water hose and nourish themselves by the leaking carbon molecules. Through the interaction of different species a multi-species biofilm can develop. Especially in the food processing environment biofilms in water hoses represent a risk factor. Within the food processing sector water hoses are often used to remove disinfecting agents from freshly cleaned surfaces, after the cleaning and disinfection procedure. When biofilms are located inside these water hoses, cells or cell clusters can detach, subsequently contaminating cleaned food contact surfaces.

We checked water hoses as a biofilm hotspot in a meat processing facility by using a flocked swab for biofilm sampling inside the water hose and accessory parts (i.e. nozzle). The bacterial load (culture-based and DNA-based) and the presence of matrix components (carbohydrates, proteins and extracellular DNA) were analysed.  

Herby we identified three from six tested water hoses to harbour a biofilm, by being positive for microorganisms and at least two matrix components. This clearly states the need for further understanding of biofilm formation in water hoses. Within the three other hoses, microorganisms could be detected, but no matrix components. We could isolate twelve genera of the water hose associated biofilms using one growth medium (TSA) and two different incubation temperatures (10 °C and 20 °C). There was only on genus that was present within all three water hose biofilms, which was Rhodococcus. Previously this genus was isolated from a shower head (Lee 2013), and is known to catabolise a wide range of organic compounds. This potentially enables the growth in a nutrient poor environment like the water hose providing secondary colonisers launch aid to contribute to the biofilm. The genera Flavobacterium, Microbacterium and Stenotrophomonas were shared among two of the water hose biofilms. Experiments to assess the biofilm forming ability of isolates of these genera using a mono-species static biofilm model indicate that all three species are able to produce matrix and can therefore be regarded as biofilm producers.

To date, there is limited information about biofilm development and presence in water hoses, especially in the food processing environment. This first identification of biofilms in water hoses and associated parts emphasizes the need of further research on this topic and detailed monitoring at these sites to prevent recontamination. A currently ongoing microbiome study on the water, the used water hoses, and the water-contacting food contact sites in a meat processing facility will give further details about the biofilm presence and possible transmission of microorganisms encountered there.

 

References:

Lee, Yoonjin. 2013. “An Evaluation of Microbial and Chemical Contamination Sources Related to the Deterioration of Tap Water Quality in the Household Water Supply System.” International Journal of Environmental Research and Public Health 10(9):4143–60.