title: Survival of Brucella abortus in milk fermented with a yoghurt starter culture.
abstract: In countries such as Mexico, brucellosis is still an important public health problem due to the consumption of non-pasteurized milk and dairy products, contaminated with Brucella spp. The aim of this study was to look into the survival of Brucella abortus during fermentation of milk with a yoghurt starter culture and storage at refrigeration temperature. Sterile skim milk was inoculated with B. abortus at two concentrations, 10(5) and 10(8) CFU/ml simultaneously with a yoghurt starter culture of lactic acid bacteria (Streptococcus thermophilus and Lactobacillus delbrueckii subspecie bulgaricus). Inoculated flasks were incubated at 42 degrees C, followed by refrigeration at 4 degrees C. Samples were taken during fermentation and during storage and viable count of B. abortus and lactic acid bacteria and pH were determined. Results showed that after 10 days of storage at 4 degrees C, B. abortus was recovered in fermented milk at a level of 10(5) CFU/ml, despite the low pH below 4.0. Therefore B. abortus is able to survive in fermented milk. This finding may imply that non-pasteurized fermented milk contaminated with Brucella abortus could be a means of transmission of these bacteria.
authors.affiliation: Departamento de Microbiologia, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Apartado Postal 4-870, 06400, DF México. zunigae@uaeh.reduaeh.mx
authors.forename: Armida
authors.initials: A
authors.lastname: Zúñiga Estrada
authors.forename: Lydia
authors.initials: L
authors.lastname: Mota de la Garza
authors.forename: Miroslava
authors.initials: M
authors.lastname: Sánchez Mendoza
authors.forename: Eva María
authors.initials: EM
authors.lastname: Santos López
authors.forename: Santiago
authors.initials: S
authors.lastname: Filardo Kerstupp
authors.forename: Ahidé
authors.initials: A
authors.lastname: López Merino
mesh_terms: D000818:Animals; D002003:Brucella abortus / Q000302:isolation & purification / Q000502:physiology*; D002006:Brucellosis / Q000382:microbiology*; D002417:Cattle; D005260:Female; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D048668:Lactobacillus delbrueckii / Q000502:physiology*; D048249:Streptococcus thermophilus / Q000502:physiology*; D013696:Temperature; D015014:Yogurt / Q000382:microbiology*