The natural microflora of Xuanwei ham in China was investigated and the results showed that there was a close relationship between yeast and ham quality. As the dominant microorganism, ham yeast played an important role in the quality of ham. Other mycelium fungi such as Penicillium and Aspergillus, which looked flourishing on the surface of ham. may not avail ham quality because they produce some mycotoxins. The quality of ham inoculated with yeast naturally isolated from ham was superior to that of traditional ones according to indices of color-fragrance-flavor and the contents of amino acids. By inoculating yeasts on ham and controlling the air humidity of ham room, a better quality ham called no-mouldy ham was developed successfully. (c) 2005 Elsevier Ltd. All rights reserved.