Aflatoxin content in three types of ready-to-eat chili paste from Bangkok markets and effect of sorbic acid on aflatoxin conncentration

Abstract

Ready-to-eat chili pastes that are traditional Thai foods consist of several ingredients and also have various tastes. Thailand is a warm and humid environment, where aflatoxin-producing fungi can grow well. The ingredients of chili paste are frequently contaminated with aflatoxins. In this study three types of ready-to-eat Thai chili paste, namprik tadang, namprik pau and namprik narok, were collected and aflatoxin levels and the levels of mixed preservatives (benzoic and sorbic acid) were determined. There were 46 out of 60 (76.67%) samples were contaminated with aflatoxin G1 and B2. Median total aflatoxins contamination of namprik tadang, namprik pau and namprik narok were 3.65, 6.26 and 1.96 ppb, with ranges of 0.39-21.67, 1.11-347.50, 0.41-13.30 ppb, respectively. The median of total mixed preservatives of namprik tadang, namprik pau and namprik narok were 855.3, 170.4 and 746.7 ppm ranges were 73.6-1679.4, 58.0-647.8 and 42.4-954.5 ppm, respectively. Namprik narok was chosen and prepared to study the effect of sorbic acid on changes in aflatoxin contents in closed and opened systems of storage. In the closed system, the range of aflatoxins increased from 0.78-0.98 ppb to 1.37-1.66 ppb (range of all twelve groups of prepared samples). No level of sorbic acid was significantly different in aflatoxin contents (p<0.05). In the Opened system, the range of aflatoxins increased from 4.11-5.30 ppb to 5.50-8.97 ppb (range of all four groups). Sorbic acid in sample was shown to completely inhibit of aflatoxin contamination because of the antimicrobial activity of sorbic acid is pH dependent. The pH of namprik narok samples was in the range in which sorbic acid which is effect. Namprik narok from markets was studied for storage conditions which affect aflatoxin contents. The ranges were about 1.01 ppb at the beginning and 4.22 ppb at the last week. (Range of all four groups). From a consumption survey, it can be concluded that 92.44% of the selected population in Bangkok had been consuming some ready-to-eat Thai ch