Use of stainless steel chips for the recovery of adhering bacteria in the pipelines of 7 french egg breaking companies

The adhesion of microorganisms to industrial surfaces is frequently observed in the food industry. Adhering bacteria can colonize the surfaces and organize into biofilms that provide cell protection against many stresses such as those due to disinfectants. Poorly controlled, they can be the source of food product contamination and/or food spoilage, and therefore may have important economical and sanitary consequences.The aim of this study was to use stainless steel chips for the identification of the type of adhering bacteria inside the pipelines of 7 French egg breaking companies.Sterile stainless steel chips were suspended inside the pipelines at two levels, before and after the pasteurizer, and at two seasons (summer and winter). After two months, the adhering flora was harvested by sonication and scrapping in tryptone salt, followed by plating onto BHI-YE and incubation for 1 to 7 day(s) at 30°C, with or without oxygen. After incubation, the colonies were identified by sequencing.The harvested cells were mainly facultative aerobic-anaerobic and Gram positive bacteria. However, a broad range of diversity was highlighted, at the location level (7 companies), at the process level (before and after pasteurization), and at the season level (summer and winter).This study, using a simple system of recovery of adhering cells, highlights the flora present on the surface of the equipments of egg breaking companies and represents the first step to better understand and control cell adhesion and biofilm development in this type of food industry