Selective enumeration and viability of Bifidobacterium animalis subsp. lactis in a new fermented milk product

Brazilian Journal of Microbiology

Adriane Elisabete Costa Antunes¹  Elza Terezinha Grael¹  Izildinha Moreno¹  Luana Gajardoni Rodrigues¹  Fernanda Martelo Dourado¹  Daniela Marques Saccaro¹  Alda Luiza Santos Lerayer¹ 

[1] ,Tecnolat Instituto de Tecnologia de Alimentos Centro de Pesquisa e Desenvolvimento de Laticínios Campinas SP ,Brasil

关键词: Mesophilic cultures;    buttermilk;    selectivity;    viability;    Buttermilk;    culturas mesofílicas;    seletividade;    viabilidade;   

DOI  :  10.1590/S1517-83822007000100035

来源: SciELO

【 摘 要 】

One of the key focuses of today's dairy industry worldwide is the continued development of new products, especially probiotic-based products. Buttermilk is originally a by-product of butter making fermented by Mesophilic Aromatic Cultures (MAC). It can also be made by fermentation of pasteurized whole milk or skimmed milk. This product is not marketed in Brazil. The objectives of this work were: (1) to develop a selective medium for Bifidobacterium animalis subsp. lactis enumeration and (2) to determine the viability of this microorganism during the shelf life of the buttermilk. Skim milk added with 10% sucrose or 0.03% sucralose was pasteurized and inoculated with a composite starter culture consisting of 1% MAC (containing Lactococcus lactis subsp. cremoris, Lactococcus lactis subsp. lactis, Lactococcus lactis subsp. lactis biovar. diacetylactis and Leuconostoc mesenteroides subsp. cremoris) and 2% Bifidobacterium animalis subsp. lactis. To attain selective counts of Bif. animalis subsp. lactis the MRS agar supplemented with 0.5% L-cysteine hydrochloride at 10%, 1% lithium chloride at 10%, 0.01% aniline blue and 0.5% dicloxacillin at 0.1% was modified by increasing the antibiotic concentration, addition of NaCl, adjusting pH to 4.8 or increasing the incubation temperature (from 37 to 45ºC). Raising the incubation temperature to 45ºC was found to be efficient in inhibiting the MAC cultures, even in media not added with dicloxacillin. Bif. animalis subsp. lactis exhibited high viability in the product. The buttermilk product prepared with sucrose and sweetener contained in excess of 10(8) cfu.ml-1 bifidobacteria throughout the shelf life of the product (28 days).

【 授权许可】

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