Ripening of Cheddar cheese made from blends of raw and pasteurised milk

Cheddar cheeses were made from pasteurised milk (P), raw milk (R) or pasteu rised milk to which 10(PR10), 5 (PR5) or 1 (PR1) % of raw milk had been add ed. Non-starter lactic acid bacteria (NSLAB) were not detectable in P chees e in the first month of ripening, at which stage PR1, PR5, PR10 and R chees es had 10(4), 10(5), 10(6) and 10(7) cfu NSLAB g(-1), respectively. After r ipening for 4 months, the number of NSLAB was 1-2 log cycles lower in P che ese than in all other cheeses. Urea-polyacrylamide gel electrophoretograms of water-soluble and insoluble fractions of cheeses and reverse-phase HPLC chromatograms of 70% (v/v) ethanol-soluble as well as-insoluble fractions o f WSF were essentially similar in all cheeses. The concentration of amino a cids were pro rata the number of NSLAB and were the highest in R cheese and the lowest in P cheese throughout ripening. Free fatty acids and most of t he fatty acid esters in 4-month old cheeses were higher in PR1, PR5, PR10 a nd R cheeses than in P cheese. Commercial graders awarded the highest flavo ur scores to 1-month-old PR1 cheeses and the lowest to P or R cheese. An ex pert panel of sensory assessors awarded increasingly higher scores for frui ty/sweet and pungent aroma as the level of raw milk increased. The trend fo r aroma intensity and perceived maturity was R > PR10 > PP5 > PR1 > P. The NSLAB from raw milk appeared to influence the ripening and quality of Chedd ar cheese. (C) 2000 Elsevier Science Ltd. All rights reserved.