Biodiversity of antifungal lactic acid bacteria isolated from raw milk samples from cow, ewe and goat over one-year period

• Published in: International journal of food microbiology 2012-04, Vol.155 (3), p.185-190
• Main Authors: Delavenne, E., Mounier, J., Déniel, F., Barbier, G., Le Blay, G.
• Format: Article
• Language: English
• Subjects: Agar; Animals; Antibiosis; Antifungal activity; Antifungal lactic acid bacteria; Biodiversity; Biological diversity; Cattle; Colonies; Colony Count, Microbial; Cow; Cow's milk; Dairy products; Ewe; Female; Fungi; Fungi - classification; Fungi - isolation & purification; Goat; Goats; Kluyveromyces - classification; Kluyveromyces - isolation & purification; Kluyveromyces lactis; Lactic Acid; Lactic acid bacteria; Lactobacillus; Lactobacillus - classification; Lactobacillus - isolation & purification; Media (selective); Milk; Milk - microbiology; Mucor plumbeus; Penicillium expansum; Pichia anomala; Reservoirs; Seasons; Sheep; Spoilage; Summer
• ISSN: 0168-1605; 1879-3460
• DOI: 10.1016/j.ijfoodmicro.2012.02.003

Antifungal lactic acid bacteria (ALAB) biodiversity was evaluated in raw milk from ewe, cow and goat over one year period. Lactic acid bacteria were enumerated using 8 semi-selective media, and systematically screened for their antifungal activity against 4 spoilage fungi commonly encountered in dairy products. Depending on the selective medium, between 0.05% (Elliker agar) and 5.5% (LAMVAB agar) screened colonies showed an antifungal activity. The great majority of these active colonies originated from cow (49%) and goat (43%) milks, whereas only 8% were isolated from ewe milk. Penicillium expansum was the most frequently inhibited fungus with 48.5% of colonies active against P. expansum among the 1235 isolated, followed by Mucor plumbeus with 30.6% of active colonies, Kluyveromyces lactis with only 12.1% of active colonies and Pichia anomala with 8.7% of active colonies. In the tested conditions, 94% of the sequenced active colonies belonged to Lactobacillus. Among them, targeted fungal species differed according to the Lactobacillus group, whose presence largely depended on year period and milk origin. The Lb. casei and Lb. reuteri groups, predominantly recovered in summer/fall, were overrepresented in the population targeting M. plumbeus, whereas isolates from the Lb. plantarum group, predominantly recovered in spring, were overrepresented in the population targeting K. lactis, the ones belonging to the Lb. buchneri group, predominantly recovered in spring, were overrepresented in the population targeting P. anomala. Raw milk, especially cow and goat milks from the summer/fall period appeared to be a productive reservoir for antifungal lactobacilli. ► Cow, ewe and goat milks were sampled to isolate antifungal lactic acid bacteria. ► 1,235 antifungal isolates were recovered among 70,000 screened colonies over one-year. ► Recovery of isolates depended on growth medium, animal, period and targeted fungus. ► Antifungal bacteria mainly came from cow and goat milks in summer/fall. ► Most isolates belonged to the Lactobacillus genus, mainly Lactobacillus casei group.