Abnormal contamination of cottage cheese in Egypt

Abstract

Chemical analyses revealed that cottage cheese is poor in organic matter and is rich in soluble salts. Na was generally high, K and Ca were moderate, whereas, Mn, Cu, Cd and Ni were detected in low concentrations. pH value was generally alkaline. Two genera of bacteria (Bacillus and Staphylococcus) in addition to Gram negative bacteria were detected. Bacillus was the most dominant. Thirty-five fungal species, which belonged to 9 genera, were detected on two isolation media (29 species belonging to 8 genera on glucose-Czapek's and 20 species belonging to 4 genera on 7.5% NaCl glucose-Czapek's agar). Aspergillus (12 and 6 species) and Penicillium (10 and 6) were the dominant genera on the two isolation media, respectively. Eurotium (6 species) was detected on halophilic medium only. Based on HPLC analysis, histamine was detected in all the 20 samples of cottage cheese (3170.8 μg g−1), of which 15 samples contained a high value (4207.7 ± 684.8 μg−1). Aflatoxins B1 and B2 (104 and 89 μg kg−1) were identified in two samples, whereas, ochratoxin A and B (112 μg kg−1) in one sample only. © Taylor & Francis Group, LLC.