The relationship between quality criteria of goat milk, its technological properties and the quality of the final products

Abstract

This paper presents the main criteria that enable the control of milk quality criteria that are included in a payment system based on goat milk quality, with regard to hygienic quality and the technological and sensorial impacts on the final products. Somatic cells, often linked to mastitis and thus to pathogens when the count is high, induce changes of the biochemical composition of milk. However, somatic cell count (SCC) does not seem to impair either cheese-making or sensorial characteristics of the cheeses for SSC close to 1,800,000 cells/ml. Some problems could, nevertheless, occur for the production of high heat-treated milks. The presence of colostrum (IgG) could impair heat-treated fluid milk production, while inhibiting substances could impair the fermentation process. Taking into account the great variability of natural inhibiting substances contained in goat milk, the bovine test applied to goat milk should be adapted. Bacteria count gives a good estimation of the hygienic quality of milk and although pathogens are also included in payment systems, these are not discussed. Nevertheless, different classes of bacteria should be distinguished due to the specific character or change each may cause, for example, psychrotrophic bacteria, which may produce heat resistant protease and lipase and induce organoleptic defects in goat milk products. The fat and protein contents in goat milk have been improved through genetics and feeding programmes. Protein percentage, however, is not a precise criterion to predict and ensure cheese yield. Casein percentage would be a more precise criterion to ensure cheese yield. The lipolysis of goat milk can be a useful optional criterion to ensure the quality of non-ripened lactic cheeses.