Metabolic characteristic of lactic acid bacteria from camel milk

Most camel milk is consumed as fermented milk: the milk is usually allowed to ferment naturally at ambient temperature without any heat treatment. Information is lacking on the microbiology of camel milk and more research is needed. In order to define the natural microbial population of whole camel milk and to create active starters, the different metabolic characteristics of some lactic acid bacteria selected from camel milk were considered. From samples of frozen camel milk 92 strains of Lactic Acid Bacteria were isolated: cocci (51) or rods (41). The study of the metabolic characteristics (gas production, sugar fermentation, growth temperatures, caseinolytic, reducing and acidifying activities) was carried out so as to compare these strains with those of cow milk. Growth at different temperature (15, 37 and 45°C) gave quite different results, as was expected: all the strains grew better at low temperatures. All the Cocci (51 strains) were homofermentative, while for the Rods 23 strains were homofermentative, 10 strains facultatively heterofermentative and 8 strains obligately heterofermentative. Lactococcus lactis ssp lactis predominated (Fig. 1). The pattern of fermented carbohydrates is sometimes unusual: 30 % of the strains were able to ferment tagatose, a sugar utilised by few species. Wide biodiversity was found for the fermentative profile within the same species and compared to the same species from other animals (cow, goat). Genotypic identification was necessary to achieve good identification for some of the 92 isolated strains. The poor rennetability of camel milk can be improved by good fermentation using some lactic acid bacteria. Thus an appropriate selection of these bacteria, and the creation of a culture collection of strains isolated from camel milk, and identified and typed for their metabolic activities to use as starter cultures, would provide improved dairy product quality from the camel.