Effect of ripening temperature on the growth and significance of non-starter lactic acad bacteria in Cheddar cheese made from raw or pasteurised milk

Two cheese-making trials were conducted, each involving four cheeses, two m ade from raw milk (R1, RS) and two from pasteurised milk (P1, P8), and ripe ned at 1 degrees C (R1, P1) or 8 degrees C (R8, P8). The 1-day-old R1 and R 8 cheese in trials 1 and 2 contained similar to 10(4) non-starter lactic ac id bacteria (NSLAB)g(-1). In trial 1, no NSLAB were detected in 1-day-old P 1 and P8 cheeses while those in trial 2 contained 10(2) cfu g(-1). In both trials, the maximum differences between the number of NSLAB in the cheeses ripened at 1 or 8 degrees C were observed at 4 months, when the number of N SLAB in cheeses ripened at 8 degrees C were 3 log cycles higher than in tho se ripened at 1 degrees C, At the end of ripening (6-months), the number of NSLAB in P8 and R8 were similar to 2 log cycles higher than in P1 and R1 c heeses, respectively. Primary proteolysis in the cheeses was markedly affec ted by ripening temperature, but not by pasteurisation of the cheese milk. Urea-polyacyrlamide gel electrophoretograms and reverse-phase (RP)-HPLC of the water-soluble fraction showed differences between cheeses made from raw or pasteurised milk and between cheeses ripened at 1 or 8 degrees C. The c oncentration of amino acids and fatty acids were in the order R8 > P8 > R1 > P1. Commercial graders awarded highest flavour scores to the Ri cheeses d uring gradings at 4, 5 and 6 months. A sensory panel found that most flavou r and aroma attributes and maturity were in the order of R8 > P8 > R1 = P1. The results of this study suggest that NSLAB play an important role in the development of flavour in Cheddar cheese by contributing to the production of amino acids and fatty acids. (C) 2000 Elsevier Science Ltd. All rights reserved.