Chloropropanol compounds are recognized as pollutants generated in food processing, including 3-chloro-1,2-propanediol (3-MCPD), 2-chloro-1,3-propanediol (2-MCPD), 1,3-dichloro-2-propanol (1,3-DCP), and 2,3-dichloro-1-propanol (2,3-dCP), among them, 3-MCPD has the highest pollution level and is often used as a reference for the detection of chloropropanols, reflecting the pollution status of chloropropanols in food processing. Foodmate will take everyone together to learn about the relevant content of 3-MCPD.

What is 3-MCPD

3-MCPD, also known as chloroglycerin and 2-chloroglycerin, is an organic intermediate chlorodiol and a common pollutant. It was first found in acid hydrolysis vegetable protein and soy sauce, and later found in other foods. 3-MCPD and its esters can be formed by glycerol or acylglycerol esters during heat treatment in the presence of chloride ions in food or food contact materials. 3-MCPD in food is mostly present in the form of fatty acid esters. Chloropropylene glycol ester is an intermediate in the formation process of 3-MCPD and also a source of 3-MCPD. There are currently no official reports of direct toxicological effects of 3-MCPD on the human body, but research has shown that long-term excessive intake can cause damage to the reproductive system and kidney function in the human body.

Pollution sources

Currently, it is widely recognized that chloropropanol ester pollution mainly comes from edible vegetable oil, and the content of 3-MCPD varies greatly after refining different oils. Some sources indicate that the content is relatively high in palm oil and relatively low in olive oil. In August 2020, the Hong Kong Consumer Council released the test results of a sample of 15 infant formulae in the market, all of which contained the kidney-damaging contaminant 3-MCPD. Therefore, special attention should be paid to foods containing fats and oils with palm oil, especially foods for infants and children.

Some countries/regions have limited requirements on 3-MCPD

Some countries/regions have regulations on the limit of 3-MCPD, as follows.

In addition, the EU has established limits for the sum of 3-MCPD and 3-MCPD fatty acid esters (denoted as 3-MCPD) in powdered milk formulae for infants and formulae for special medical purposes. Among them, the content in powdered infant formula and special medical use formula should not exceed 125μg/kg, and in liquid infant formula and special medical use formula should not exceed 15μg/kg.

Controlling the pathway of 3-MCPD formation

More studies have shown that the formation of 3-MCPD can be controlled in several ways:

(Ⅰ) Reduce the content of precursor substances in raw materials and select refined vegetable oil produced through improved processes in raw material procurement.

(Ⅱ) The content of 3-MCPD in the final product can be effectively reduced by using adsorbent materials or additives, removing precursors, degrading by enzymatic reaction and short distillation during the refining process.

(Ⅲ) Reducing the deodorization temperature, shortening the deodorization time, and avoiding the use of water during the refining process can also effectively reduce the content of 3-MCPD.

(Ⅳ) Research on the formation mechanism and reduction methods of 3-MCPD needs to be strengthened in order to inhibit 3-MCPD production more efficiently and safely, as well as to reduce the amount of 3-MCPD produced in the oil refining process.