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 myc ological 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 ml 1 for table butter, cooking butter and kareish chees e 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 , Geotrich um 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 chees e were Candida spp., Rhodotorula spp., and Saccharomyces spp. The isolated moulds and yeasts w ere evaluated for proteolytic and lipolytic activities on Tributyrin .Aflatoxin M 1 was detected in 4 kareish cheese samples in a vari able levels ranging from 5 to 35 ppb. The economic and public hsignificance of isolated moulds and yeasts as well as the sanitary precautions were dis cussed.