Cheese brine regeneration treatments in a dairy factory.

In the dairy industry brine is very important technologically, and for a cheese factory it can be considered a patrimony, thus it must undergo constant monitoring and adequate regeneration. The present work was aimed at monitoring, for approximately 18 months, different brines employed for soft and semi-hard cheeses in a medium sized dairy factory, situated in Valtellina (North Italy). Evaluations were made of the microbiological characteristics (Standard Bacterial Count, coliforms, Escherichia coli, yeasts and moulds) and of the effectiveness of the purification treatments adopted for the brine i.e., first, its filtration and then its microfiltration. The microbiological analyses revealed that the brines were relatively free of a high degree of contamination, except for a few sporadic cases. Both the physical regeneration methods, filtration and microfiltration of the brine, were effective purification systems, although microfiltration was found to be more advantageous from the point of view of system management. In experimental brines we also tested the use of chemicals, hydrogen peroxide and sodium hypochlorite, two disinfectants chosen their antimicrobial activity, and assessed their effect on the aspect and taste of the cheeses. The addition of hydrogen peroxide in a single step was effective against alotolerant microorganisms, coliforms, and E. coli but not against moulds and yeasts, while sodium hypochlorite, added every day at low concentration, resulted in a progressive reduction of all the microorganisms. The obtained data confirm the importance of monitoring brines and the importance of brine regeneration treatments, particularly microfiltration.