Biochemical and microbiological events of Parma ham production technology.

Parma ham technology relies on a few basic points. They are: a fresh meat substantially free of microbial deep contamination, a relatively long phase (up to 100 days) at cold temperatures at the beginning of processing, an uncovered muscular surface as reduced as possible, a long period of maturation. The final product, the matured ham, is the result of a slow process of dehydration which, combined with a limited penetration of salt into the muscles, lowers the water activity to values around 0.90. Surface bacterial contamination is mainly made up by Enterobacteriaceae and Pseudomonadaceae. Among them E. agglomerans and S. liquefaciens are able to grow at 2 degrees C and salt concentrations up to 7.5% and can be responsible for taint development. Micrococci penetrate into the meat during salting and can reach values of 10 x 6 but decrease substantially towards the end of maturation. Maturation, from a biochemical point of view, is characterized by hydrolytic phenomena interesting nitrogen compounds and fats. As a result free amino acids, non protein nitrogen, volatile fatty acids and carbonylic molecules are produced. Such products are important for the development of typical organoleptic characters.