In three different dairies (A, B and C) located in Peloponess region (Southern Greece), traditional Feta cheese trials took place February to March using mixtures of sheep's and goat's milk. Only ...small variations in the evolution of microbial groups were observed during the whole ripening period. The main groups, such as thermophilic cocci, mesophilic lactococci, thermophilic lactobacilli, nonstarter lactic acid bacteria (NSLAB), presumptive
Leuconostoc, enterococci and micrococci, reached their highest levels during the first 16 days, and then declined approximately 1–2 log units until the end of ripening. The remaining groups investigated, comprising yeasts, coliforms and
Escherichia coli, were highest at day 4. The yeasts remained constant, while coliforms and
E. coli decreased sharply and were not detectable after 120 days of ripening. A number of 146 isolates (dairy A) taken from all stages of the manufacturing and ripening process were purified and studied.
Lactobacillus plantarum (58/146) and isolates of related species
Lactobacillus pentosus and
Lactobacillus paraplantarum (16/146) were the most common microorganisms found during cheese ripening.
Streptococcus thermophilus (23/146) and
Lactobacillus delbrueckii subsp.
bulgaricus (20/146) were detected in high levels up to 20 days, and then gradually reduced.
Enterococcus faecium (29/146) was found in all manufacturing and ripening stages.
Teleme cheese was made from ovine, caprine and bovine milk with thermophilic (Streptococcus thermophilus, Lactobacillus delbrueckii subsp. bulgaricus), mesophilic (Lactococcus lactis subsp. lactis, ...Lactococcus lactis subsp. cremoris) and mixed thermophilic-mesophilic (1:1) cultures. Nine lots of cheese each time (five repetitions) were made in order to study the proteolysis of cheeses during ripening and storage up to 6 months. All cheeses showed similar profiles of proteolysis. However, the rate of proteolysis was different. The thermophilic and the mesophilic cultures resulted in cheeses with the highest and the lowest degree of proteolysis, respectively. Proteolysis was of a descending order in cheeses made from sheep's, goat's and cow's milk when estimated on the basis of nitrogenous fractions (total nitrogen, water soluble nitrogen, nitrogen soluble in 5% phosphotungstic acid and nitrogen soluble in 12% trichloroacetic acid), whereas it was highest in cow's milk cheeses and lowest in goat's milk cheeses when estimated on the basis of electrophoresis and RP-HPLC. Multivariate analysis of the data revealed that cheeses could be more correctly clustered by the type of milk or culture than by the stage of ripening.
The separation of cows', sheep's and goats' milk casein components by HPLC on a strong anion-exchange (P.L-SAX 8 mu 1000A) column is described. During HLPC, whole caseins of the three kinds of milk ...behaved differently from conventional separations. The casein components of the three kinds of milk were well resolved under the chromatographic conditions used. HPLC resolved the kappa-caseins better than did ion-exchange chromatography on DEAE cellulose, and was particularly efficient in the case of goats' milk. Goats' and sheep's milks had almost similar chromatographic profiles but these differed considerably from that of cows' milk. Caseins from the sheep and the goat were also similar in that a shallower NaCl gradient was required for the separation of casein components than for cows' milk.
Excretion rates in milk of sodium penicillin G, streptopenicillin, oxytetracycline, and chlortetracycline given to sheep by intramuscular injection or intramammary infusion were studied. When given ...by intramuscular injection, penicillin G and streptopenicillin were excreted in milk for 24h, oxytetracycline for 38h, and chlortetracycline for 72h. The corresponding times following intramammary infusion were 72 to 86h, 72 to 86h, 96 to 110h, and 110 to 120h. Concentrations in milk of penicillin, streptopenicillin, and oxytetracycline given by intramuscular injection made it unsuitable for yogurt production for 24h. Chlortetracycline, although excreted in milk longer, did not affect yogurt production. When antibiotics were given by intramammary infusion, they were excreted in milk in concentrations harmful for yogurt production for 72, 72, 96, and 116h.
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