No abstract

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.

No abstract

The present study examined the influence of the manufacturing time on proteolysis and sensory characteristics of Idiazabal cheese. Samples of Idiazabal cheeses made using traditional manufacturing methods at two different times of year were collected at a plant operating under the auspices of the Idiazabal Cheese Appellation of Origin. The cheeses were made in February and June, roughly the beginning and the end of the manufacturing season. Chemical analyses were performed on d 1, 90, and 180 of ripening and sensory analyses on d 90, 120, and 180 of ripening. Higher nitrogen fraction (soluble and nonprotein nitrogen) levels and free amino acid contents were observed in the cheeses manufactured during the month of June. Degradation of the alphas- and beta-caseins was also greater in the cheeses made at that time of year. The cheeses manufactured in February earned higher sensory analysis scores for characteristic odor and taste and higher total sensory scores. The cheeses manufactured in June earned higher scores for the sensory attributes sweet flavor and bitter taste.