The development of free volatile fatty acids (FVFA) in Ras cheese treated with lipases was investigated. Ras cheese was made with the addition of Italase, Capalase K and Capalase KL and then analysed periodically for the FVFA by quantitative gas-liquid chromatography. Lipase treatment markedly increased the total FVFA content of the cheese during storage, particularly when Capalase K was used. The FVFA of Ras cheese were found to consist of propionic, butyric, caproic, caprylic and traces of acetic acid. The relative concentration of FVFA varied with storage and lipase treatment.

Changes in microbial flora during the cheese-making and maturation processes of Spanish mould-ripened Cabrales cheese have been studied. In the interior of the cheese lactic streptococci, mainly Streptococcus lactis, predominated before and during salting (0–4 d); Str. lactis and lactic acid-utilizing yeasts during dryingroom ripening (5–15 d); moulds, mainly Penicillium roqueforti, and lactobacilli, mainly Lactobacillus plantarum, predominated during cave-ripening (16–120 d). On the cheese surface Str. lactis was the majority flora before and during salting; Str. lactis, micrococci and leuconostocs were the main microbial groups during drying-room ripening, and micrococci throughout cave-ripening. Coliforms and coagulase-positive staphylococci died off during the first month of maturation.