Chapter 12. The Formation of 3-Monochloropropane-1,2-diol (3-MCPD) in Food and Potential Measures of Control

Summary

The findings of 3-MCPD in foods such as roasted cereals, bread, toasted bread, non-HVP seasonings, cheese, cooked meat, etc. have attracted significant attention in the past years. Despite the widespread occurrence of the food-borne contaminant 3-MCPD, the mechanisms of its formation have not been studied in much detail in foods other than acid-hydrolysed vegetable protein (acid-HVP). Several reports focused mainly on model systems attempt to describe the underlying reaction mechanisms of 3-MCPD formation in the different foods, and essentially two very basic pathways can be described, i.e. thermally driven and enzyme catalyzed reactions. The latter involves the action of lipases upon “bound” or esterified MCPD, also termed chloroesters. Lipases can originate from different sources (e.g. microbial) and catalyze the hydrolysis of MCPD esters and subsequently release 3-MCPD. This pathway may be valid in products that contain ingredients with lipase activity together with fat which may contain low amounts of the intermediate chloroesters. On the other hand, heat-driven mechanisms seem predominant in roasted cereals, bread crust and toast, and are correlated to the degree of browning of the product. They are, however, also dependent on the availability of the direct precursors, i.e. mainly glycerol and chloride. The rate of formation of 3-MCPD in simple dough systems has been shown to be dependent on several salient parameters such as the moisture content, temperature/ time and pH. Based on the recent studies related to better understanding the formation of 3-MCPD in different foods, several options have been proposed to control or lower 3-MCPD. However, most of the mitigation research that has been conducted in non-acid HVP products is at laboratory or pilot scale using rather simple models. This report summarizes the main reaction pathways to 3-MCPD in the key food categories, highlighting potential options for reduction. Clearly, more research into the mechanisms of formation of 3-MCPD and related compounds in food systems is warranted, and any reduction strategies must also take into account the potential impact on the formation of other “undesired” compounds without compromising on the quality and safety of food.