Résumé:
Microbial contamination of surfaces remains a topical issue in many sectors of the agri-food industry, particularly in the dairy sector. The presence in collected milk of a diverse microbial flora, constituting dairy biofilms native to livestock farms, is alarming for dairy industry professionals, as these contaminants are recognized as the source of major economic and health problems. In this study, we were able to isolate strains of Staphylococcus aureus and Bacillus cereus from rinsing water recovered from a CIP cleaning-in-place of a dairy's fresh milk reception line. Our contribution was to characterize bacterial biofilm patterns on a dairy receiving line (i.e. spoilage and pathogenic flora), carry out cleaning kinetics and model them in order to optimize CIP with available equipment. Our scientific contribution was to
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discriminate between the respective actions of each stage or activity involved in cleaning, i.e. soaking by hydration in treated water combined with chemical attack, rinsing by mechanical action alone, cleaning by combining mechanical action with chemical action. This approach has enabled us to put forward solutions for combating the contaminants characterized as initiators of dangerous dairy biofilms, and to explain the response to be modeled by the action of physical, biological and/or chemical phenomena. Bacterial inactivation is more or less easily eliminated by an adapted mechanical action, linked to chemistry via concentration, combining the passage of two solutions, one alkaline and the other acidic, to a biocidal disinfection.
