摘要：

Lactobacilli constitute the majority of nonstarter lactic acid bacteria (NSLAB) in Cheddar cheese. Species predominating are Lactobacillus casei, Lactobacillus plantarum, and Lactobacillus brevis. Typical cell densities in Cheddar cheese range from 10 to 104/g during the first 10 d to about 108/g within a few weeks postmanufacture. Numbers in cheese are affected by numbers in raw milk and the extent of postpasteurization contamination. Lactobacilli sustain growth in cheese depleted of fermentable carbohydrate by metabolizing peptides, amino acids, sugars released from enzymic hydrolysis of casein, and products of degrading starter bacteria. Lactobacilli, which require several amino acids for growth, possess numerous proteases and peptidases. Peptidases produced by L. casei include dipeptidase, tripeptidase, carboxypeptidase, aminopeptidase, and endopeptidase. Results have been variable in numerous experiments testing the use of selected lactobacilli as adjuncts to lactic starter culture for cheese ripening. Results depended on numbers, strain, type of cheese, and condition of manufacture. Shocking lactobacilli with heat, freezing, lysozyme, ultrasound, organic solvents, or alkaline conditions has been used to minimize proteolytic activity while enhancing peptidolysis. These efforts to accelerate cheese ripening by increasing amounts of active peptidases have been only partially successful.

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