3-monochloropropane diol (3-MCPD), 3-MCPD esters and glycidyl esters

GE formation is directly associated with elevated temperatures and how long they are at these temperatures. They are generally formed from diacylglycerols with no requirement for the presence of chlorinated compounds.

3-MCPD and related substances have been found in a wide range of foods, with the highest levels being in fats and oils, as reported in the EFSA study: ‘3-MCPD occurrence in food in Europe’.  Other foodstuffs also reported included: foods for infants and small children; composite foods; grains and cereal based products; herbs; condiments; dressings; meat and meat products; potato and potato products; protein and amino acid supplements.  In cereal derived products it is understood that commonly added salt is one of the major precursors and glycerol another.  Glycerol and chloride react together during the baking stage to form 3-MCPD.  Other compounds also form 3-MCPD on reaction with chloride, various substituted glycerols and phospholipids.  Fatty acid esters of 3-MCPD have been found in high levels in refined edible oils and fats and derived foods, including milk powder for infants by the German control authorities.

Contributors to be possible factors in 3-MCPD and related substance formation include:

• naturally occurring levels in raw materials
• storage of raw materials
• use of chlorinated water for washing purposes
• the level of diacetyl glycerol (DAG) and polar compounds in fats and oils
• high temperatures during processing
• commercial food processing including baking, evaporation, fermentation, malting, pasteurisation, roasting, smoking, spray drying, sterilisation and UHT
• migration from food contact materials
• storage of prepared products
• domestic food preparation including baking, boiling, frying, grilling and toasting.

Legislation European Commission Regulation (EC) No.1881/2006 prescribes maximum levels of 3-MCPD of 0.02 mg/kg (20μg/kg) for HVP and soy sauce.  In the case of the soy sauce, the limit is based on a product containing 40% dry matter [corresponding to a maximum level of 0.05mg/kg (50μg/kg) in dry matter].

This was revised with (EC) No. 2020/1322 setting maximum levels for GE’s and 3-MCPD  across vegetable oils and fats, fish oils and oils from other marine organisms, placed on the market for the final consumer, or for use as an ingredient in food, infant formulae, and foods for special medical purposes intended for infants and young children applying from 1 January 2021. Levels were not set for virgin olive oils as this does not contain 3-MCPD and/or GE. Many of the levels set have been established with a view to a review, and a lowering of the permitted levels, within 2 years’.

COMMISSION REGULATION (EU) 2020/1322 of 23 September 2020 amending Regulation (EC) No 1881/2006 as regards maximum levels of 3‐monochloropropanediol (3-MCPD), 3-MCPD fatty acid esters and glycidyl fatty acid esters in certain foods.

In cases where the mechanism of formation is understood, measures can be taken to reduce the levels of the precursors and adapt processing conditions to reduce overall levels in the finished product.  Any reduction measures need to ensure a comprehensive HACCP review considering impact to chemical, microbiological and physical hazards for the target consumer group. In addition to quality parameters and consumer acceptance which also need to be reviewed.