[Enterococci and coliforms in yellow sheep cheese].

Abstract

The developmental dynamic of enterococci and coliforms was followed up in the entire technologic process and the storage of kashkaval (yellow cheese of ewe milk) under the conditions of modern industrial production. It was found that during the whole industrial cycle up to the steam cooking of curd the amount of enterococci grew and reached its peak value in the cheddarized cheese curd (2.4--30 million per gram), increasing from 10 to 34 times as against its level in the initial milk used. The coliform bacteria also rose in number, and their amount reached maximum values of 10 to 120 mill/g in the processed and dipped curd, after which a slowly advancing reduction set in. Species of the Enterobacter (55.1%), Escherichia (14.1%), Citrobacter (19.2%), and Klebsiella (11.5%) genera were isolated. The steam cooking of cheddarized curd produced an unfavourable effect on enterococci (pasteurization effect of up to 98.3 to 99.9%) and a lethal effect on the coliforms. Enterococci that resisted steaming multiplied in kashkaval and reached their highest level--960 000 up to 39 mill/g--between the 30th and the 60th day of production after which their numbers dropped. Their amount in the ripened product varied from 95000 to 17.8 mill/g, and on the 240th following production--from below 100 to 1.6 mill/g. Coliform bacteria were not found in 0.1 g of the product mass during ripening and storage of kashkaval. Out of the 196 strains that were differentiated as enterococci 30.7 per cent of the fecalis subgroup, and 69.3 per cent--of the Sp. faecium-durans subgroup. After steaming 92.3 per cent of the strains were of the Str. faecium and Str. durans species.