Effects of storage on the major constituents of raw milk

Milk testing and quality control should be carried out at all stages of the dairy chain. Milk can be tested for quantity, organoleptic characteristic, compositional characteristic, physical and chemical characteristics, hygienic characteristics, adulteration or drug residues. The content of the major constituents of raw milk is important for milk payment system. Enzymes naturally present in the milk can change the chemical composition of raw milk. Also, enzymes secreted by bacteria or enzymes from somatic cells can degrade the raw milk composition. Products of these degradation reactions can have undesirable effects on milk structure, smell and taste. It is very important that farm-fresh raw milk be cooled immediately to not more than 8 °C in the case of daily collection, or not more than 6 °C if collection is not daily. During transport the cold chain must be maintained. An authorized person, properly trained in the appropriate technique, shall perform sampling of bulk milk in farm. Laboratory samples should be dispatched immediately after sampling to the dairy company and consequently to the testing laboratory. The time for dispatch of the samples to the testing laboratory should be as short as possible, preferably within 24 h. Laboratory samples shall be transported and stored at temperature 1 to 5 °C. Higher temperatures may adversely affect the composition of the laboratory sample and may cause disputes between the farmer, the dairy company and the laboratory. The effect of refrigerated storage at temperature 4 °C during 24 h on the composition of raw milk were investigated in this work, because we wanted to know how the milk composition will be changed and how the laboratory results will be affected. In many cases, the samples are not preserved with chemical preservants like azidiol, bronopol, potassium dichromate or Microtabs. We found, that the composition of raw cows' milk after 24 was changed significantly (p >0.005). We found an average decrease in the fat content of -0.04 g/100g, increase in the protein content of +0.02 g/100g, increase in the lactose content of +0.02 g/100g, increase in the solid-not-fat content of +0.02 g/100g and decrease in the total solid content of -0.02 g/100g. It is necessary to cool the raw cows' milk after the milking to decrease the changes in milk composition caused mainly due to the lipolytic activity of lipase

Fatty acid profile of traditional Slovak ewe’s and cow’s lump cheese

ABSTRACTThe main goal of the research was to find out how the profile and content of individual fatty acids changes in Slovak ewe and cow’s lump cheeses (TSG – Traditional Specialty Guaranteed by European Union). Local farmer produced the cheese. We have analyzed 94 samples of cheeses produced during the production season by the GC/FID method. Fatty acids were found in various concentrations. The following fatty acids were present in the highest concentrations in Ewe’s lump cheese: palmitic acid C16:0 (25.67–35.59 g/100 g), oleic acid C18:1 (n-9) (16.26–25.92 g 100 g−1), myristic acid C14:0 (10.15–14.41 g 100 g−1) and and stearic acid C18:0 (7.23–10.95 g 100 g−1); in Cow’s lump cheese palmitic acid C16:0 (29.46–36.94 g/100 g), oleic acid C18:1 (n-9) (18.93–26.54 g 100 g−1), myristic acid C14:0 (10.07–13.26 g 100 g−1 and stearic acid C18:0 (8.13–10.44 g 100 g−1). Significant (p < .005) changes in individual fatty acid concentrations was found over the production season for most fatty acids. Small farmers can learn the technological process of producing TSG products, but it is important to consider particular seasonal changes in the quantity of fat and fatty acids. From a nutritional perspective, high vaccenic acid concentrations are advantageous, whereas high saturated myristic and palmitic acid concentrations are dubious. The results of this research can be used to supplement the national specification of the TSG Slovak traditional Ewe’s lump cheese (Ovčí hrudkový syr – salašnícky)