Estimation of folate in milk by microbiological assay using trienzyme extraction method.

摘要

Use of a modified microbiological assay for the analysis of folate in milk is reported. The modified assay includes an additional trienzyme extraction (using proteinase, alpha-amylase and conjugase, in that order) along with the standard microbiological assay which measures spectroscopically growth of Lactobacillus rhamnosus in a casein based medium. The applicability of the method for the assay of cows', buffaloes', ewes' or goats' milk samples collected in and around Karnal City, India, was evaluated. The estimated average values of folate in milk from goats, cows, ewes and buffaloes were 10, 44 , 56 and 60 mug/l, respectively. Buffaloes' milk was the richest source of folate among the milk samples analysed. The performance of this method was evaluated by comparing the folate levels obtained using it with those available in the literature. It is concluded that estimation of the total folate concn. in milk using this method, though a little labour intensive, is highly selective, sensitive and reproducible.