Incidence of lipolytic and proteolytic fungi in some milk products and their public health significance

ABSTRACT

A total of sixty random samples of dairy products; 20 of either table butter, cooking butter or kareish cheese; were collected and subjected to mycological and mycotoxicological evaluation. The mean total mould counts were 7.3X 10[1] +/- 6X10[1, 1.8] X10[3] +/- 5.4X 10[2] and 4.1X 10[3] +/- 3.1 X 10[3] cfu m[-1] for table butter, cooking butter and kareish cheese samples respectively. Respective yeast counts were 1 X10[3] +/- 6.1 X 10[2], 3.3 X 10[4] +/- 3 X 10[4] and 1.5 X 10[4] +/- 1.3 X 10[4] cfu ml-1. The highest frequency distribution of all examined samples for mould and yeast counts lies within the range 10 -100 / gm. Aspergillus niger, A. flavus, Geotrichum spp. and Mucor spp. were isolated from the examined samples at varying percentages of 8.3- 41.7. The predominant species of yeasts isolated from table butter, cooking butter and kareish cheese were Candida spp., Rhodotorula spp., and Saccharomyces spp. The isolated moulds and yeasts were evaluated for proteolytic and lipolytic activities on Tributyrin .Aflatoxin M1 was detected in 4 kareish cheese samples in a variable levels ranging from 5 to 35 ppb. The economic and public health significance of isolated moulds and yeasts as well as the sanitary precautions were discussed