Klila, an Algerian cheese produced in steppe and mountainous areas, is proving increasingly popular with consumers. It is traditionally made with ewe, goat or cow milk, leading to a product with high dry matter content (> 90%). In this work, we have characterized three different Klila cheeses made with the three different milks using physico-chemical and microbiological parameters. A triangle test was also performed on naïve consumers, and the three types of Klila were clearly distinguished by sensory analysis. They exhibited distinct features, in particular very low Aw (< 0.5) and pH values (< 4.5) preserving them from pathogens. Lactobacilli and enterococci were counted at low levels (< 4 log (cfu)/g) as well as some spore-forming bacteria (< 3 log (cfu)/g). Colonies were picked from MRS and BEA media. They were identified by sequencing and characterized on their ability to produce lactic acid and using REP-PCR. Lb plantarum was the main species isolated, followed by Pediococcus pentosaceus, Leuconostoc pseudomesenteroïdes and Lactobacillus fermentum. The Enterococcus genus was dominated by Ec durans, Ec faecium and Ec hirae. Among these two main populations, different subgroups were observed by means of the REP-PCR profiles and the lactic acid production of the isolates. Some strains were found in two and even three cheeses. We suppose that these microbes are representative of the environmental context in which Klila is produced.

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The Lactococcus diversity in cow and goat raw milk was investigated. To do so, a protocol had to be established for the specific enumeration of lactococci. Eight agar media and one control medium were analysed to compare their proficiency in evaluating the Lactococcus population in raw milk: M17 Nal, Elliker, modified Elliker, PCA + milk, modified KCA, modified Chalmers, Turner, FSDA. The M17 medium was used as reference. Eighteen pure strains were tested on these media for their selectivity towards lactococci: six Lactococcus species or subspecies, three Leuconostoc, three Enterococcus, two Lactobacillus, one Streptococcus thermophilus, one Pseudomonas fluorescens, one Escherichia coli and one Staphylococcus aureus. All these bacteria were chosen for their regular presence in raw milk. The KCA medium proved to be the most selective towards lactococci, on condition that 1) we discriminated the colonies using the catalase test and 2) we subtracted the Enterococcus population counted on BEA. However, it was not possible to separate the Streptococcus from the Lactococcus colonies on KCA. The "Lactococcus-like" population including these two genera was estimated at a mean level of 3.18 log(cfu)/mL and 4.14 log(cfu)/mL in cow and goat raw milk respectively. This is consistent with the data already published.

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