Role of Enterococci in Cheddar Cheese: Proteolytic Activity and Lactic Acid Development1

Abstract

Eight lots of Cheddar cheese were manufactured by using two strains of Streptococcus faecalis and Streptococcus durans in combination with a commercial lactic culture. Each lot consisted of a control vat of cheese, manufactured with lactic starter only, and an experimental vat of cheese containing the lactic starter and one of the enterococcus strains. Combinations of two curing temperatures (7.2 and 12.8 C) and two early cooling treatments (air vs. brine cooling) were used for cheeses from each vat to determine the effects of these handling procedures, as well as of enterococcus addition, on proteolysis and lactic acid development. These characteristics were monitored from milling to up to 6 months of curing. Cheeses manufactured with S. faecalis exhibited more protein breakdown than did the control cheeses and those made with S. durans, the latter two being nearly identical in the extent of proteolysis. More proteolysis was consistently observed in those cheeses cured at 12.8 C. No statistical difference was observed inproteolytic activity between air- and brine-cooled cheeses. Cheeses made with S. durans had a higher final percentage of lactic acid than did controls and cheeses made with S. faecalis. Cheeses manufactured with enterococci exhibited a more rapid initial production of lactate. Cheeses cured at 12.8 C had greater percentages of lactic acid compared with those cured at 7.2 C. Air-cooled cheeses also developed significantly higher levels of lactic acid than did brine-cooled cheeses.