Microbiological studies on some soft cheeses in Taiz city

ABSTRACT

This investigation aims to study the effect of different storage temeratures on the microorganisms and keeping quality of local and imported soft cheeses. The samples were taken from different markets in Taiz City, Republic of Yemen. Both local and imported soft cheeses samples were stored at 28, 10 and 4°C. The samples stored at 28°C were used as control samples. Microbiological changes were followed by examination of samples during storage at zero time and weekly [every 7 days] for a period of 60 days until signs of spoilage appeared. The results indicated that cold storage at 10°C reduced the contamination for the Aerobic, Anaerobic, Spore formers, Lactic acid bacteria, Coliform group, Salmonella spp, Staphylococcus spp, Streptococcus spp, Bacillus spp, Clostridium spp, Enterococcl spp, Proteolytic bacteria, Psychrophilic bacteria and Yeast and Moulds counts by the following percentages 47.63 and 50.10%, 31.66 and 36.50%, 28.32 and 24.84%, 33.33 and 33.89%, 35.44and 33.80%, 36.76 and 37.80%, 42.50 and 42.50%, 37.06 and 34.39%, 33.90 and 34.92%, 34.95 and 38.87%, 38.73 and 39.64%, 57.55 and 50.76%, 33.07 and 30.37% and 45.61 and 47.37% of local and imported soft cheeses respectively as compared with their control samples.. Also the cold storage at 4 °C induced a reduction by the following percentages52.16 and 53.75%, 33.33 and 39,18%, 38.22 and 34.74%, 39.96 and 49.32%, 38.23 and 42.00%, 41.10 and 42.95%, 45.60 and 50.00%,38.98 and 36.24%, 36.87 and 37.66%, 36.1 and 46.83%, 46.60 and 59.13%, 59.95 and 66.00%, 42.51% and 43.45% and 62.71 and 63.43%for the mentioned microbes and samples, respectively as compared with their control samples. However, the shelf-life were increased by 21and 37 days when using a cold storage at 10 °C and extended by 30 and 60 days when using a cold storage at 4 °C of local and imported soft cheeses, respectively as compared with their control samples. As well as the isolation and classification of [65] bacterial isolates from the above samples, those bacteria identified as [27] of Bacillus spp, and [38] of Lactic 0cand/spp, both species divided into five groups