The Influence of Cleaning and Sanitizing on Enterobacteriaceae, Coliforms, and E. coli Presence in Rendered Fat Transportation Tankers Used for the Pet Food Industry

The objective of this research was to evaluate the presence of microbial indicators before and after cleaning and disinfection practices. Three truck wash facilities were selected, and nine tanker trailers were sampled at each station in four sites. Samples were collected before and after the washing step with a sterile sponge stick, transferred in buffer peptone water. Serial dilutions were plated for Enterobacteriaceae, coliforms, and E. coli. No detectable population was recovered in facility A before or after the washing step. In facility B no coliforms were detected before or after the washing step, while Enterobacteriaceae were enumerated before washing at the pump (2.49 log CFU/cm2) and outlet (1.67 log CFU/ cm2). In facility C no coliforms were observed before or after washing. Enterobacteriaceae were enumerated (3.06 log CFU/cm2) at the outlet. These three samples were analyzed for metagenomic, and Pseudomonas was the species taxonomically more abundant. Statistical analysis highlighted that the washing step significantly influenced microbial populations, while the interaction between washing step and location was significant only for Enterobacteriaceae (P<0.05). This preliminary study emphasized the need to standardize procedures and processing times at wash stations to facilitate the implementation of effective cleaning and disinfection protocols.