Heavy Metal Contamination and Allicin in Shallots and Garlic in Srisaket Province, Thailand

Heavy metal (HM) contamination in economic crops is a recognized global concern, causing serious health hazards for consumers and having negative impacts on national economies. This study aimed to investigate HM contamination levels of crops of shallots and garlic around Srisaket Province, reputed to be the best quality grown in Thailand. Their functional groups of allicin were studied using Fourier-transform infrared spectroscopy, and the concentrations of HMs for commonly consumed shallots and garlic in 7 districts of Srisaket Province with a total of 38 samples, were determined using atomic absorption spectroscopy. The results found that their functional groups comprised hydroxyl, carbonyl, carboxylic and organosulfur compounds, and the concentrations of Pb, Cd, Cu, and Zn in shallots and garlic were at safe levels for the permissible limits set by the Ministry of Public Health in Thailand, Codex Alimentarius Commission, and Ministry of Health of the People’s Republic of China. The concentrations ranged from 0.013-0.061mg Pb/kg, 0.001-0.003mgCd/kg, 1.268-4.365mgCu/kg, and 5.585-11.265mgZn/kg. This is the first pilot study and report on concentrations of HMs in edible shallots and garlic in Srisaket Province, Thailand. The data can be used as preliminary information for both Thai and overseas consumers to consider the measurement of safe consumption of both crops.