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Kouřimská L., Legarová V., Panovská Z., Pánek J. (2014): Quality of cows' milk from organic and conventional farming. Czech J. Food Sci., 32: 398-405.The results of chemical and microbial analyses of raw milk samples coming from organic and conventional farming systems were statistically compared. The samples were analysed during a twelve-month period (June-May). A total of 2206 samples were collected of which 528 were organic. After raw milk was processed, sensory hedonic quality of 171 pairs of organic and conventional non-standardised pasteurised whole milk samples were evaluated using the pair comparison preference test. Four parameters in raw milk, free fatty acids, urea content, somatic cell count and coliform bacteria count, showed no significant differences between the two types of production. Significantly higher contents of protein, casein, lactose, and non-fat solids were detected in conventional milk, which also had a significantly lower freezing point. On the contrary, significantly higher contents of total mesophilic bacteria count and a higher percentage of samples with positive coliform bacteria count were found in organic milk samples. Sensory analysis of pasteurised milk showed no significant hedonic difference between organic and conventional samples.

We compare visual evaluation of yolk colour estimated by the usual method applying La Roche scale with spectrophotometric determination of β-carotene by AOAC method, and by new rapid analyser iCheck^TM Egg photometer (BioAnalyt). The eggs under consideration were purchased on a current Czech market. The eggs originated from various countries and various types of breeding including some specialities. The yolk colour varied between the values of 4–13 of La Roche scale. The carotenoid content expressed as β-carotene measured by AOAC method varied between 11–87 mg/kg. The carotenoid content expressed as β-carotene measured with the analyser iCheck^TM Egg photometer was lower and varied between 7.5–68.5 mg/kg. The correlation between the colour hue measured visually and the carotenoid content was not proved. Slovak eggs from cages which contained 28.3 mg carotenoids in 1 kg of yolk had the darkest yolks (value 13), Czech bio eggs which contained 20.2 mg carotenoids in 1 kg of yolk had the palest yolks (value 6). The highest content of carotenoids was found in eggs from home hen breeding (72.5 mg carotenoids in 1 kg of yolk) whose colour hue had the value of 10.

Methoxypyrazines are the principal aroma components responsible for the vegetative and herbaceous green bell-pepper flavour of Sauvignon blanc wines produced in Moravia. The aroma profiles of 8 samples of Moravian Sauvignon wines were analysed; the levels of 3-isobutyl-2-methoxypyrazine varied in the range of 4.7-17.0 ng/l. The commercial Sauvignon aroma preparation Aroma Fantasia S, available in the region, was analysed; the product contained the 3-isobutyl-2-methoxypyrazine, and in negligible concentrations also anethol and ethylbenzoate. The Moravian Sauvignon blanc wine samples spiked with different amounts of aroma preparation were evaluated by hedonic sensory analysis, to estimate the meaningfulness of such illegal improvement. The most preferred concentration ranged from 5 ng/l to 10 ng/l, which are the natural levels of MP in Moravian Sauvignon blanc wines, therefore the addition of aroma at this level, which can be detectable with difficulties, has no reason. The less sophisticated adulteration of wine, such as the production of artificial Sauvignon blanc wine by the addition of MP into less distinctive wines, is easily detectable according to the aroma profile.