3-MCPD (3-monochloropropane-1,2-diolor3-chloropropane-1,2-diol) is an organicchemical compound with the formula HOCH2CH(OH)CH2Cl. It is a colorless liquid. It is a versatile multifunctional building block.[1] The compound has attracted attention as the most common member of chemical food contaminants known as chloropropanols.[2] It is suspected to be carcinogenic in humans.
3-MCPD is thought to be produced when foods are treated at high temperatures with hydrochloric acid. Such treatments are sometimes used to accelerate protein hydrolysis, making food more digestable. In such a treatment chloride is thought to react with the glycerol backbone of lipids to produce 3-MCPD. 3-MCPD is also thought to arise in foods that have been in contact with materials containing epichlorohydrin-based wet-strength resins which are used in the production of some tea bags and sausage casings.[3]
Chlorination of glycerol gives the 3-MCPD:
HOCH(CH2OH)2 + HCl → HOCH(CH2Cl)(CH2OH) + H2O
The same compound can be produced by hydrolysis of epichlorohydrin.[4]
The joint Food Standards Australia New Zealand (FSANZ) set a limit for 3-MCPD in soy sauce of 0.02 mg/kg, in line with European Commission standards which came into force in the EU in April 2002.
In 2000, a survey of soy sauces and similar products available in the UK was carried out by the Joint Ministry of Agriculture, Fisheries and Food/Department of Health Food Safety and Standards Group (JFSSG) and reported more than half of the samples collected from retail outlets contained various levels of 3-MCPD.[14]
In 2001, the United Kingdom Food Standards Agency (FSA) found in tests of various oyster sauces and soy sauces that 22% of samples contained 3-MCPD at levels considerably higher than those deemed safe by the European Union. About two-thirds of these samples also contained a second chloropropanol called 1,3-dichloropropane-2-ol (1,3-DCP) which experts advise should not be present at any levels in food. Both chemicals have the potential to cause cancer and the Agency recommended that the affected products be withdrawn from shelves and avoided.[15][16]
In 2001, the FSA and Food Standards Australia New Zealand (FSANZ) singled out brands and products imported from Thailand, China, Hong Kong, and Taiwan. Brands named in the British warning include Golden Mountain, King Imperial, Pearl River Bridge, Golden Mark, Kimlan, Golden Swan, Sinsin, Tung Chun, and Wanjasham soy sauce. Knorr soy sauce was also implicated, as well as Uni-President Enterprises Corporationcreamy soy sauce from Taiwan, Silver Swan soy sauce from the Philippines, Ta Tun soy bean sauce from Taiwan, Tau Vi Yeu seasoning sauce and Soya bean sauce from Vietnam, Zu Miao Fo Shan soy superior sauce and Mushroom soy sauce from China and Golden Mountain and Lee Kum Kee chicken marinade.[17][18][19]
Between 2002 and 2004, relatively high levels of 3-MCPD and other chloropropanols were found in soy sauce and other foods in China.[20]
In 2007, in Vietnam, 3-MCPD was found in toxic levels. In 2004, the HCM City Institute of Hygiene and Public Health found 33 of 41 sample of soy sauce with high rates of 3-MCPD, including six samples with up to 11,000 to 18,000 times more 3-MPCD than permitted, an increase over 23 to 5,644 times in 2001,[21] The newspaper Thanh Nien Daily commented, "Health agencies have known that Vietnamese soy sauce, the country's second most popular sauce after fish sauce, has been chock full of cancer agents since at least 2001."[22]
In March 2008, in Australia, "carcinogens" were found in soy sauces, and Australians were advised to avoid soy sauce.[23]
In November 2008, Britain's Food Standards Agency reported a wide range of household name food products from sliced bread to crackers, beefburgers and cheese with 3-MCPD above safe limits. Relatively high levels of the chemical were found in popular brands such as Mother's Pride, Jacobs crackers, John West, Kraft Dairylea and McVitie's Krackawheat. The same study also found relatively high levels in a range of supermarket own-brands, including Tesco char-grilled beefburgers, Sainsbury's Hot 'n Spicy Chicken Drumsticks and digestive biscuits from Asda. The highest levels of 3-MCPD found in a non- soy sauce product, crackers, was 134 μg per kg. The highest level of 3-MCPD found in soy sauce was 93,000 μg per kg, 700 times higher. The legal limit for 3-MCPD coming in next year[when?] will be 20 μg per kg, but the safety guideline on daily intake is 120 μg for a 60 kg person per day.[citation needed]
In 2016, the occurrence of 3-MCPD in selected paper products (coffee filters, tea bags, disposable paper hot beverage cups, milk paperboard containers, paper towels) sold on the Canadian and German market was reported and the transfer of 3-MCPD from those products to beverages was investigated.[24] Exposure to 3-MCPD from packaging material would likely constitute only a small percentage of overall dietary exposure when compared to the intake of processed oils/fats containing 3-MCPD equivalent (in form of fatty acid esters) which are often present at levels of about 0.2-2 μg/g.
^Bodén, Lennart; Lundgren, Michael; Stensiö, Karl-Erland; Gorzynski, Marek (1997-11-14). "Determination of 1,3-dichloro-2-propanol and 3-chloro-1,2-propanediol in papers treated with polyamidoamine-epichlorohydrin wet-strength resins by gas chromatography-mass spectrometry using selective ion monitoring". Journal of Chromatography A. 788 (1): 195–203. doi:10.1016/S0021-9673(97)00711-5.
^Macarthur R, Crews C, Davies A, Brereton P, Hough P, Harvey D (November 2000). "3-monochloropropane-1,2-diol (3-MCPD) in soy sauces and similar products available from retail outlets in the UK". Food Additives and Contaminants. 17 (11): 903–6. doi:10.1080/026520300750038072. PMID11271703. S2CID45724146.
^Fu WS, Zhao Y, Zhang G, et al. (August 2007). "Occurrence of chloropropanols in soy sauce and other foods in China between 2002 and 2004". Food Additives and Contaminants. 24 (8): 812–9. doi:10.1080/02652030701246039. PMID17613068. S2CID20880307.
^Becalski, Adam; Zhao, Tony; Breton, Francois; Kuhlmann, Jan (2016-09-01). "2- and 3-Monochloropropanediols in paper products and their transfer to foods". Food Additives & Contaminants: Part A. 33 (9): 1499–1508. doi:10.1080/19440049.2016.1223353. ISSN1944-0049. PMID27598381. S2CID25763740.
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