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D P. TO R RE . 2000. The evolution of physicochemical parameters, and the most important microbial groups, were determined for the following three batches of 'Cameros' goat's milk cheese during ripening: Batch R elaborated with raw milk, Batch RS elaborated with raw milk and with the addition of a starter culture, and Batch PS elaborated with pasteurized milk and with the addition of the same culture. No differences in total solids (TS) or in the content of NaCl, fat and total nitrogen (expressed as percentages of TS) were found during the ripening. The pH, fat acidity and non-protein nitrogen (NPN, expressed as a percentage of TN) showed significant differences between the batches. The inoculated batches showed the fastest drop in pH at the beginning of the ripening period, but the cheeses of Batch R showed a higher degree of lipolysis and proteolysis. The addition of a starter influenced the microbiological quality of the cheeses. Differences in the counts of Enterobacteriaceae and faecal coliforms were found between Batches R and RS after 15 days. Staphylococcus aureus increased in number during the early period of ripening and attained a population above 6 log cfu g −1 in Batch R in the period from 5 to 10 days. However, enterotoxins were not detected in this Batch. Batch R showed lower values of lactic acid bacteria at the beginning of the ripening period, but no significant differences were found between batches in the period from 5 to 15 days of ripening. At the beginning of the ripening, Lactococcus was the main lactic acid bacteria, with L. lactis lactis being predominant. After 15 days, the lactic acid bacteria counts decreased in the three batches, especially in the cheeses of Batch PS (only 2·2 log cfu g −1 was found at 60 days), as lactococci (the only lactic acid bacteria present in Batch PS) are incapable of growing under the conditions found in cheeses at the end of their ripening period. At this time, Lactobacillus was the predominant genus in Batches R and RS, with L. plantarum predominant. No lactococci were found from day 30 in Batch R and from day 40 in Batch RS. The cheeses of Batch RS received the most favourable scores from the tasting panel for all attributes judged: cut appearance, colour, aroma, taste, texture and general acceptance.

Forty eight honeys from the La Rioja region of Spain were analysed to establish their quality. Fourteen legally required parameters of quality control were measured. Samples were obtained from two geographic areas of production : Valley and Sierra. These areas present different agroclimatic conditions and, thus, different flora. Classification of these honeys according to their geographic origin was achieved by applying multivariate statistical analysis to the chemical and physical data. Acidity (free acidity and pH), mineral content (electrical conductivity and ash) and factors related to degree of freshness (hydroxymethylfurfural and diastatic activity), were found to be the most important features for classification. Determination of the geographic origin of a La Rioja honey (Valley or Sierra) was possible with 83% accuracy using only these legally required quality control parameters; pollen studies were not necessary to achieve this objective.

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Twenty-one samples from the Cantabrian coast were analyzed to establish their microbiological quality and fermentation tendency. In a food with a very low free-water content like honey, microbiological growth is only possible when there is an increase in water activity. Since most of the samples studied were not extensively granulated, the risk of fermentation is mostly due to high water content. Among our samples, only two had a water content below 17.1% (no risk of fermentation), whereas the high water activity of the rest of the samples indicates the possibility of microbial growth. In fact, four of the samples analyzed showed a moisture content over the Spanish maximum legal limit, which means a high risk of fermentation. The absence of Enterobacteriaceae, coliforms, and Escherichia coli in our samples indicates an appropriate cleanliness during extractions and handling of honey. No Salmonella or Shigella were found. The relationship between water activity and mold and yeast counts found for the honeys analyzed allowed us to divide our samples in two groups: honeys with a high or a low risk of fermentation. Changes observed during storage of the samples confirmed this classification.