Quality evaluation of Vietnam traditional soy sauce concerning nutritional composition and aflatoxin criteria

Abstract

Soy sauce (Tương) is a traditional Vietnamese fermented dipping sauce, known for its high nutritional value and cultural significance. However, the production process poses potential risks of contamination by pathogenic microorganisms and mycotoxins (aflatoxins). This study aimed to evaluate the quality and safety of tương through three main indicators: reducing sugar content, soluble protein content, and total aflatoxin levels in 38 samples collected from Hung Yen, Hanoi, Ha Nam, and Nghe An. The results showed that 35 out of 38 samples had aflatoxin levels below the detection limit (LOD = 0.74 µg/kg), while 3 samples from smallscale producers had levels above the LOD but still within the permissible limits set by QCVN 8-1:2011/BYT. Soluble protein content in the completed products ranged from 5.05% to 6.61%, and reducing sugar varied widely between 2.26% and 10.04%. These findings provide a scientific evidence for assessing the current quality status of traditional tương products and suggest directions for improving the production process to enhance and stabilize nutritional value and food safety of the product.