The importance of biogenic amines stems from their toxicity and their potential as a cause of food poisoning. After fish, cheese has been the foodstuff most often responsible for cases of food poisoning caused by ingestion of biogenic amines. Changes in biogenic amine (histamine, tyramine, putrescine, cadaverine, tryptamine, isopentylamine, spermidine, and phenylethylamine) content during the ripening of a cheese made from raw ewe's milk were studied, together with the effects of pasteurization and a commonly used commercial starter and indigenous starter cultures. Biogenic amines were determined by high-pressure liquid chromatography following extraction from the cheese and derivatization with dansyl chloride. Levels of histamine, potentially the most toxic amine, in the semihard Idiazábal cheese were very low. Tyramine, putrescine, and cadaverine were the main amines present in this type of cheese. Levels of those amines increased during ripening. Pasteurization of the milk brought about a reduction in the biogenic amine content of the ripened cheese, irrespective of the starter culture employed. The indigenous starter cultures considered in this study produced higher levels of histamine and cadaverine and lower levels of tyramine and putrescine than the commercial starter culture tested.

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The present study considers the influence of reducing the fat content of ovine milk on the sensory and instrumental texture characteristics of the resulting cheeses. Three manufacturing runs were performed. In each run three cheese batches were manufactured using milks with differing percentage fat contents (8%, 4%, and 2% fat). Analysis of cheese samples was performed at 60, 90, and 120 days of ripening. The instrumental method used to evaluate cheese texture was uniaxial compression at constant speed, taking readings of stress, strain, and modulus of elasticity (E). Statisticalanalysis revealed differences forboth the differentfat contents and the ripening times considered. Instrumental parameter values increased with lower cheese fat contents; with a 20% reduction in the fat to dry matter content from full‐fat to reduced‐fat cheeses, resulting in a 35% increase in maximum stress and in the slope of the stress‐strain curve at the end of ripening. The greatest sensory differences between samples were recorded for firmness.

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Idiazabal cheese is an uncooked pressed cheese, with Appellation of Origin, elaborated with raw ewes' milk. The seasonal characteristic of the Idiazabal cheese, together with other factors such as physical, chemical and microbiological features of the milk, as well as climatic and geographic conditions, can have an influence upon the sensory properties of cheese. The wide acceptance of ewes' milk cheese in Spain and the fact that no sensory characterization studies have been developed for the Idiazdbal cheese led to the realization of the present work, that aims at characterization of the cheese from a sensory standpoint and at describing its degree of homogeneity taking into account factors such as the month and cheese factory of elaboration. After carrying out the Quantitative Descriptive Analysis, which included 22 descriptors, and through a jury of specialists, factor analysis enabled us to classify Idiazabal cheese as a slightly pungent cheese in odor, flavor and aftertaste, with its own characteristic flavor and a firm, moderately grainy texture. Nonetheless, a signijicant degree of heterogeneity was observed among the samples.