Resumen

BERROCAL, Darling; ARIAS, María Laura; HENDERSON, Marjorie  y  WONG, Eric. Evaluación de la actividad de cultivos probióticos sobre Listeria monocytogenes durante la producción y almacenamiento de yogur. ALAN [online]. 2002, vol.52, n.4, pp.375-380. ISSN 0004-0622.

Evaluation of the effect of probiotic cultures over Listeria monocytogenes during the production and storage of yogurt. The effect of probiotic cultures over Listeria monocytogenes during the production and storage of yogurt was evaluated. A yogurt mixture (10,6% non-fat solid liquids, 3% fat and 0,3% gelatin) was prepared, homogenized and pasteurized. Yogurt was inoculated with 0, 10², 10⁴ and 10⁶ CFU/mL of L. monocytogenes and 0,02% of traditional lactic culture YC 180 (Streptococcus thermophilus and Lactobacillus bulgaricus) and probiotic culture ABY-1 (Bifidobacterium longum, B. bifidum, B, infantis, Lactobacillus acidophilus, Streptococcus thermophilus y Lactobacillus delbrueckii subsp. bulgaricus). It was incubated for 3h at 43ºC until pH reached an approximate value of 4,8, followed by refrigeration at 5ºC for 21 days. During fermentation, samples were taken every hour, and during storage every 3 days, analyzing pH and lactic, bifidobacteria and pathogen count for each time. It was demonstrated that there was no significant simple effect for the type of culture used (ABY-1 and YC 180) (p=0,684) over the amount of L. monocytogenes present in yogurt during the fermentation and storage periods. The presence of bifidobacteria in the ABY-1 culture did not present a significant effect over L. monocytogenes. Neither the effect of time presented a significant effect over L. monocytogenes (p=0,448). In this case, the ABY-1 and YC 180 cultures present a bacteriostatic effect over the pathogen. The probiotic cultures had a bacteriostatic but not bactericidal effect over L. monocytogenes. This is not related to the protective effect of these cultures in bowel, since in-vivo conditions favor the production of antimicrobial substances, such as bacteriocins that act over pathogens.

Palabras clave : Yogurt; probiotics; Listeria monocytogenes.