Microbiological quality of ayib, a traditional Ethiopian cottage cheese.

One-hundred samples of ayib, a traditional Ethiopian cottage cheese, were purchased from Awassa market and analysed for their aerobic mesophilic counts, psychrotrophic counts, yeasts and molds, coliforms, spore-formers, enterococci, lactic acid bacteria. Listeria monocytogenes, staphylococci and Bacillus cereus. The majority of the samples showed counts of mesophilic aerobic bacteria, yeasts and enterococci of 10(8), 10(7) and 10(7) cfu/g. About 55% of the samples were positive for coliforms and faecal coliforms. Listeria spp. were not detected in any of the samples. B. cereus and S. aureus were isolated at varying frequencies but at low numbers (10(2)-10(3)). The pH value of the samples varied between 3.3 and 4.6 with about 40% having pH lower than 3.7.