Nongluck Ruangwises

Occurrence of aflatoxin M1 in pasteurized milk of the School Milk Project in Thailand.

Concentrations of aflatoxin M1 (AFM1) were determined in 150 pasteurized milk samples from the School Milk Project in Thailand. Milk samples were collected from 50 schools in the Central region of Thailand in three seasons: summer (May to June 2006), the rainy season (August to September 2006), and winter (December 2006 to January 2007). AFM1 was isolated by using an immunoaffinity column and quantified by high-performance liquid chromatography. All of the 150 pasteurized milk samples were contaminated with AFM1, and the concentrations were within the U.S. regulatory limit of 0.5 microg/liter. The highest concentration of AFM1 found in school milk samples was 0.114 microg/liter. The mean concentration of AFM1 in milk samples collected in winter was significantly higher than the mean concentrations found in the rainy season and summer. Further monitoring of school milk to evaluate the status of contamination of AFM1 is necessary, with a special emphasis on samples collected in the rainy season and winter. Thailand is one of several countries that have no regulatory limits for AFM1 in milk and milk products. The results of this study suggest that safety limits for AFM1 are needed for regulating and ensuring the quality of milk and milk products in Thailand.

Total and inorganic arsenic in rice and rice bran purchased in Thailand.

Concentrations of total and inorganic arsenic were determined in 180 samples of polished and brown rice of three rice types, namely white, jasmine, and sticky, and 44 samples of rice bran from these three rice types purchased in Thailand. Concentrations (expressed in nanograms per gram) of inorganic arsenic in polished white, jasmine, and sticky rice were 68.3 ± 17.6 (with a range of 45.0 to 106), 68.4 ± 15.6 (41.7 to 101), and 75.9 ± 24.8 (43.5 to 156), respectively, while those in the three brown rice samples were 124 ± 34.4 (74.5 to 193), 120 ± 31.6 (73.1 to 174), and 131 ± 35.6 (78.0 to 188), respectively. Inorganic arsenic concentrations (expressed in nanograms per gram) in rice bran produced from the three rice types were 633 ± 182 (375 to 919), 599 ± 112 (447 to 824), and 673 ± 195 (436 to 1,071), respectively. Rice bran contained concentrations of total and inorganic arsenic approximately seven and nine times higher, respectively, than those found in the corresponding polished rice. The levels of inorganic arsenic in the three rice types of both polished and brown rice were within the only published regulatory limit of 200 ng/g.

Heavy metals in green mussels (Perna viridis) from the Gulf of Thailand.

Concentrations of seven heavy metals were determined in green mussels (Perna viridis) collected between April and June 1995 from eight locations along the costal area of the Gulf of Thailand. The average concentrations (n = 96) of the heavy metals detected in mussel samples, on the basis of dry weight, were 1.20 mg kg-1 cadmium, 0.78 mg kg-1 for chromium, 9.85 mg kg-1 for copper, 1.09 mg kg-1 for lead 2.78 mg kg-1 for manganese, 1.54 mg kg-1 for nickel, and 94,48 mg kg-1 for zinc. The levels of cadmium, chromium, nickel, and lead found in green mussels from four locations in the Upper Gulf were significantly (P < 0.05) higher than those detected in mussels from four locations in the Lower Gulf, while the levels of copper, manganese, and zinc did not differ significantly (P > 0.05) between the Upper and Lower Gulf. Comparison with earlier studies revealed that the concentrations of some metals in the mussels collected from the Upper Gulf are increasing. The concentrations of heavy metals in green mussels from the Gulf of Thailand were within acceptable levels for human consumption.

Persistent organochlorine pesticide residues in green mussels (Perna viridis) from the Gulf of Thailand

Abstract Concentrations of BHCs (α, β, γ, and δ isomers), HCB, aldrin, dieldrin, endrin, heptachlor, heptachlor epoxide, and DDT compounds ( o , p ′- and p , p ′-isomers of DDT, DDD, and DDE) were determined in green mussels ( Perna viridis ) collected from nine locations along the coastal area of the Gulf of Thailand in May 1991. Residues of aldrin, dieldrin, and DDT compounds were detected in all samples. The other pesticides were found either at very low concentrations in a few samples or below detection limits. Non-DDT pesticide levels found in the present study showed a decrease, whereas DDT compounds seemed to remain unchanged in the average values in comparison to the data of the previous study conducted 2 years earlier.

Concentrations of total and inorganic arsenic in fresh fish, mollusks, and crustaceans from the Gulf of Thailand.

Concentrations of total and inorganic arsenic were determined in 120 samples of eight marine animals collected from the Gulf of Thailand between March and May 2008. Two species with the highest annual catch from each of four marine animal groups were analyzed: fish (Indo-Pacific mackerel and goldstripe sardine), bivalves (green mussel and blood cockle), cephalopods (pharaoh cuttlefish and Indian squid), and crustaceans (banana prawn and swimming crab). Concentrations of inorganic arsenic based on wet weight ranged from 0.012 μg/g in Indian squids to 0.603 μg/g in blood cockles. Average percentages of inorganic arsenic with respect to total arsenic ranged from 1.2% in banana prawns to 7.3% in blood cockles. Blood cockles also exhibited the highest levels of total arsenic (5.26 ± 2.01 μg/g) and inorganic arsenic (0.352 ± 0.148 μg/g). The levels of inorganic arsenic in the study samples were much lower than the Thai regulatory limit of 2 μg/g (wet wt) and hence are safe for human consumption.

Total and Inorganic Arsenic Contents in Some Edible Zingiberaceous Rhizomes in Thailand

The arsenic accumulation in rhizomes of Zingiberaceous plants was determined by atomic absorption spectrometry interfaced with hydride generation system (HG-AAS). The raw herbal materials, rhizomes, were collected from different regions of Thailand between December 2011 and January 2012. Six well-known Zingiberaceous plants, 16 samples from each and a total of 96 samples, were analyzed Alpinia galanga (Khaa), Boesenbergia rotunda (Kra-chaai), Curcuma longa (Khamin-chan), Curcuma zedoaria (Khamin-oi), Zingiber cassumunar (Plai) and Zingiber officinale (Ginger). Concentrations of total arsenic based on dry weight were 92.4 ± 9.2, 103.5 ± 20.8, 61.7 ± 12.5, 89.8 ± 17.5, 106.7 ± 19.5 and 69.3 ± 11.8 ng/g, respectively and inorganic arsenic were 48.8 ± 7.0, 66.3 ± 12.7, 25.5 ± 5.0, 38.7 ± 4.7, 71.2 ± 11.6, and 38.5 ± 5.5 ng/g, respectively. Among these, Plai and Kra-chaai exhibited the highest levels of total arsenic and inorganic arsenic accumulation that remind consumers to be aware of excess consuming of these rhizomes. On the contrary, the lowest value found in Khamin-chan indicating natural dietary supplements and herbal medicines comprising Kamin-chan are safe from arsenic poison. All investigated amounts of total and inorganic arsenic were much lower than limits recommended by Thai Food and Drug Administration.

Total and inorganic arsenic in freshwater fish and prawn in Thailand.

Total and inorganic arsenic levels were determined in 120 samples of eight freshwater animal species collected from five distribution centers in the central region of Thailand between January and March 2011. Eight species with the highest annual catch, consisting of seven fish species and one prawn species, were analyzed. Concentrations of inorganic arsenic (on a wet weight basis) ranged from 0.010 μg/g in giant prawn (Macrobrachium rosenbergii) to 0.230 μg/g in striped snakehead (Channa striata). Climbing perch (Anabas testudineus) exhibited the highest mean concentrations of total arsenic (0.459 ± 0.137 μg/g), inorganic arsenic (0.121 ± 0.044 μg/g), and percentage of inorganic arsenic (26.2%). Inorganic arsenic levels found in freshwater animals in this study were much lower than the Thai regulatory standard of 2 μg/g.

Comparative Analysis of Rhein Content in Cassia fistula Pod Extract by Thin-Layer Chromatographic-Densitometric and TLC Image Methods

A simple, rapid, and cost-effective thin-layer chromatography (TLC) image analysis was developed and validated to quantify rhein content in Cassia fistula pod pulp extract. ImageJ software was used in the proposed method, and its data were compared to TLC-densitometric data. The TLC image analysis method promoted acceptable validation parameters, showing linear relationship with r2 = 0.9988 in the concentration range of 400–1200 ng spot−1. The limit of detection (LOD) and limit of quantification (LOQ) were 84.60 and 256.36 ng spot−1, respectively. The paired t-test showed no statistically significant difference (P > 0.05) between the mean content of rhein performed by these two methods. TLC image analysis is reliable and can be used as an alternative analytical method for rhein content in C. fistula pod pulp extract and its finished products.

Estimated Daily Intake of Aflatoxin M1 in Thailand

Aflatoxins are a group of mycotoxins produced by certain species of Aspergillus. These molds grow on a variety of food and feed commodities and produce aflatoxins under appropriate temperature and humidity (Jay et al., 2005). Aflatoxin B1 (AFB1) is the most potent hepatocarcinogen of this group of mycotoxins. Aflatoxin M1 (AFM1) is a hydroxylated metabolite of AFB1 and is secreted in the milk of mammals that have eaten contaminated foods. AFM1 is also a hepatocarcinogen and is classified in Group 1 (carcinogenic to humans) by the International Agency for Research on Cancer (IARC, 2002). Exposure to AFM1 through milk products is considered to be a serious public health problem. Several countries have established regulatory limits for AFM1 in raw milk and milk products, which vary from country to country. According to the Food and Agriculture Organization of the United Nations (FAO), there are 60 countries that have established regulatory limits for AFM1; the values vary from ND (not detectable) to 15 μg/L (FAO, 2004). The two most prevalent limits are 0.05 μg/L (34 countries) and 0.5 μg/L (22 countries). The European Community has set the maximum permitted level for AFM1 in infant formulae and follow-on formulae, including infant milk and follow-on milk, at 0.025 μg/kg, and in raw milk and heat-treated milk at 0.05 μg/kg (European Commission, 2006). The U.S. regulatory limit for AFM1 is 0.5 μg/L (FAO, 2004). However, several countries, including Thailand, have not yet established regulatory limits for AFM1. The Notification of the Ministry of Public Health No. 265 – the law that regulates the quality of milk products in Thailand – only states that ‘‘...milk products may be contaminated with aflatoxins at a level that is not harmful to human health’’ (Ministry of Public Health, 2003). A national food consumption survey was conducted in Thailand during the years 2002–2004; 18,746 participants were divided into five age groups (Groups 1–5): 0–3, >3–9, >9–19, >19–65, and >65 yr (National Bureau of Agricultural Commodity and Food Standards, 2006). The survey showed that the consumption amounts of four types of milk products – milk powder, school milk, commercial pasteurized milk, and UHT (ultra-high-temperature) milk – comprised approximately 93% of all milk products consumed by the Thai population

Occurrence of Aflatoxin M1 in Raw and Pasteurized Goat Milk in Thailand

Aflatoxins are a group of structurally related mycotoxins produced by certain species of the genus Aspergillus, particularly A. flavus, A. parasiticus and A. nomius, which can grow on a variety of food and feed commodities [1]. Aflatoxin production is influenced by several fac‐ tors: for example, temperature and humidity [2]. It has been shown that aflatoxin B1 (AFB1) is the most potent hepatocarcinogen of this group of mycotoxins. Aflatoxin M1 (AFM1) is a hydroxylated metabolite of AFB1 produced by the hepatic microsomal cytochrome P450, and is secreted in the milk of mammals that have consumed AFB1-contaminated foods. AFM1 is also a hepatocarcinogen and is classified in Group 1 as carcinogenic to humans by the International Agency for Research on Cancer [3]. In terms of food safety and public health concerns, exposure to AFM1 through milk products is considered to be a serious problem.