[Methods of preserving strains of enterococci and evaluation of the technological properties as a function of storage...

The preservation possibilities of eight enterococci strains were studied following different techniques. The strains were selected considering their technological properties, specially their diacetyl and acetaldehyde producing capacities which favour their use in the cheese industry. The conservation methods tried out were: modified Sordelli, adsorption on anhydrous silica gel, periodical transfers and preservation in distilled water, salt solution and phosphate buffer solutions. The conservation capacity was evaluated during six months; the bacteria were reactivated monthly and viability, acid power and diacetyl and acetaldehyde production capacity were tested. The microorganisms preserved either by periodical transfers, or in distilled water, salt solution and phosphate buffer solutions, lost their viability and suffered deep changes into their technological properties before thirty days. On the other hand, those bacteria preserved following the modified Sordelli's method and by adsorption on anhydrous silica gel kept ther viability (Table 1), acid power (Table 2) and flavor compounds production capacity (Tables 3 and 4) until six months later. These results show that modified Sordelli's method and the anhydrous silica gel are equally efficient to preserve the enterococci properties being simplicity and lower cost of the latter an additional advantage.