Evaluation of enzymatic cleaning on the microbial flora of installations and the food products in a processed food industry

Introduction: Biofilms is a permanent source of contamination in food industries and could harbor various type of microorganisms such as spoilage bacteria. The biofilms are very resistant to conventional cleaning and disinfection methods. New strategies are proposed to eradicate them such as enzymatic cleaning.
Purpose: The purpose of this study was to evaluate the impact of the enzymatic cleaning on the microbial flora on the installations of a processed food industry and in the final food product.
Methods: A food company producing Italian dishes was monitored for 3 months. During different cleaning treatments: conventional cleaning, reinforced enzymatic cleaning and routine enzymatic cleaning. During the period of trials, all factors remained constant and only the cleaning solutions were replaced in the sanitation treatments. A total of 244 samples were analyzed, including surface samples pipes and finished products (lasagna at day 0, at the end of shelf life) by classical microbiology and 16S rDNA metagenetic. Statistical analysis (non parametric tests and principal component analysis) was carried out on with the R project software with different packages.
Results: A significant difference of the total flora concentration was observed in the food samples at the beginning of the shelf life between conventional and enzymatic cleaning (P<0,05) with a reduction of 2 log CFU/g . Metagenetic analysis of the food samples at the end of the shelf life showed statistically significant differences of the bacterial flora between conventional and enzymatic cleaning (P<0,05) with a decrease of 41% a spoiling bacteria (Leuconostoc sp., Pseudomonas sp. Enterobacteriaceae). The metagenetic analysis of the surfaces indicate a significant change of the bacterial flora (P<0,05) after the enzymatic treatment with the removal of the most predominant spoiling bacteria.
Significance: The results indicates a significant decrease of spoiling bacteria in the food installations and in food products after the enzymatic cleaning.