Microbial and chemical analysis of Chihuahua cheese and relationship to histamine and tyramine

Freshly made Mexican white cheese, "Queso Chihuahua" obtained in Chihuahua and Hermosillo, Mexico, was analyzed. An initial representative sample was taken to determine microbial quality, chemical composition and amine content. The remainder was cut into portions and randomized for storage at 5 or 25 degrees C. Representative samples were taken at 4, 8 and 12 days for analysis. Chihuahua cheese contained 43.7% fat, 49.2% protein, 2.7% salt, and 45% moisture. Water activity was 0.95 and pH 2.52. No pathogens were isolated. However, aerophilic plate count and coliforms exceeded permissible levels. Initially, amines were low, but increased during storage as proteolysis occurred. PH, salt and protein had the greatest influence on amine production