Isolation and Identification of Adherent Gram-Negative Microorganisms from Four Meat-Processing Facilities

Biofilms are described as a matrix of microorganisms which have adhered to and colonized a surface. Once formed, biofilms are difficult to remove and may be a source of contamination in food-processing environments. In this study, stainless-steel chips were fixed to surfaces adjacent to food-contact surfaces and cast-iron chips were suspended in the floor drains of four meat-processing plants. Biofilm formation was quantified by staining the attached cells and viewing them under epifluorescence microscopy. The stainless-steel and cast-iron chips removed from the plant environment showed some attached microorganisms. Floor drains appeared to provide an excellent environment for the formation of biofilms. Pseudomonas , Klebsiella , Aeromonas , and Hafnia species were identified as gram-negative microorganisms associated with the test surfaces.