Lactic acid bacteria have been used for centuries as protective agents in fermented foods. These bacteria are present in a wide variety of foods, fermented milk, yoghurts, cheeses and fermented meat products. The contamination of food by pathogenic germs is a major problem for the consumer, especially in the summer period when food poisoning appears. To fight against these germs involved in these intoxications, strains of lactic acid bacteria have been isolated and identified from raw goat milk in the western regions of the country. Thus, different strains of commercial or scientific interest are commonly isolated. The study of interactions revealed that Lactobacillus plantarum significantly decreases the growth of Staphylococcus aureus after 24 hours it is 1.6 log cfu is zero after 72 hours. The different tests reveal the protein nature of this substance involved in the inhibition of Staphylococcus aureus.