Evaluation of enzymatic cleaning in a processed food industry

Introduction
Biofilms are a permanent source of contamination in food industries and could harbour a various type of microorganisms such as pathogens and spoilage bacteria 1. The biofilms are very resistant to conventional cleaning and disinfection methods 2. New strategies are proposed to eradicate them such as enzymatic cleaning 3. The purpose of the biofilm expert project was to evaluate the impact of the enzymatic cleaning on the microbial flora on the installations and in the final food product of several food industries.
Materials and 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 was carried out on with the R project software with different packages.
Discussion
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 and spore forming bacteria). The results of 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. In conclusions, the results indicate a significant decrease of spoiling bacteria in the food installations and in food products after enzymatic cleaning.