A critical review of the occurrence of 3-chloro-propane-1,2-diol (3-MCPD) in foods not known to contain hydrolysed vegetable proteins is presented. The review covers the properties and chemistry of 3-MCPD and the current methods of analysis in foodstuffs. The results of UK surveys of 3-MCPD occurrence in both retail foods and commercial food ingredients are discussed with particular reference to cereal, meat and dairy products. The possible mechanisms for the formation and decay of 3-MCPD in foods are suggested. The review does not cover the detailed toxicology of 3-MCPD and its occurrence in hydrolysed vegetable proteins, which have been considered elsewhere, nor possible issues such as in-vivo formation.

Esters of 2 - and 3-monochloropropane-1,2-diol (MCPD) and glycidol esters are important contaminants of processed edible oils used as foods or food ingredients. This review describes the occurrence and analysis of MCPD esters and glycidol esters in vegetable oils and some other foods. The focus is on the analytical methods based on both direct and indirect methods. Methods of analysis applied to oils and lipid extracts of foods have been based on transesterification to free MCPD and determination by gas chromatography-mass spectrometry (indirect methods) and by high-performance liquid chromatography-mass spectrometry (direct methods). The evolution and performance of the different methods is described and their advantages and disadvantages are discussed. The application of direct and indirect methods to the analysis of foods and to research studies is described. The metabolism and fate of MCPD esters and glycidol esters in biological systems and the methods used to study these in body tissues studies are described. A clear understanding of the chemistry of the methods is important when choosing those suitable for the desired application, and will contribute to the mitigation of these contaminants.

Pilot-scale bread, biscuit, and cracker doughs have been baked to assess how well recipe changes could reduce acrylamide in commercial bakery products. Removing ammonium-based raising agents was beneficial in biscuits. In doughs, long yeast fermentations were an effective way of reducing asparagine levels and hence acrylamide. At moderate fermentation times fructose levels increased, but the yeast later absorbed this, so the net effect on acrylamide was beneficial. Metal ions such as calcium reduced acrylamide when added as the carbonate or chloride. Hence, the fortification of flour with calcium carbonate, over and above its natural mineral content, has an additional benefit. However, some other possible methods of adding calcium to bakery doughs, for example, via the permitted preservative calcium propionate, were not beneficial. Amino acid addition to doughs gave modest reductions in acrylamide. Lowering the dough pH reduced acrylamide, but at the expense of higher levels of other process contaminants such as 3-monochloropropane-1,2-diol (3-MCPD).

In March 2006, a joint workshop was organized by the European Commission and the Confederation of EU Food and Drink Industries (CIAA) to discuss current knowledge and achievements in the reduction of acrylamide levels. This paper focuses on the progress made with cereal products. At present, the reduction options available are applicable to a limited number of cereal products and are product-specific. The following are the most promising: * Adjustment of time and temperature during baking. * Extend fermentation times where feasible. * Substitution of ammonium bicarbonate with alternatives where feasible. * Avoid or minimise use of reducing sugars where possible. * Maintenance of uniform control of the colour and avoidance of very high baking temperature where possible. The most promising near-term technical solution is the use of asparaginase. This enzyme has the potential to achieve a 60-90% reduction for some products made from dough or batter, which can be held for a time. In the longer term, the optimisation of agronomy and plant breeding for wheat has the potential to reduce acrylamide in all foods on any scale, whether domestic or industrial. Importantly, nutritional and toxicological issues, other than acrylamide, must also be considered so as to ensure that the steps taken to reduce acrylamide levels do not have other adverse effects on diet.

Although chloropropanols have historically been associated with the savoury food ingredient hydrolyzed vegetable protein (HVP), prepared by acid hydrolysis, the discovery of significant amounts of 3-chloropropane-1,2-diol (3-CPD) 'bound' as fatty acid esters in foodstuffs (3-CPD esters), especially in refined edible oils, is still a relatively recent discovery. The toxicological significance of these 3-CPD esters and their potential contribution to the dietary intake of non-esterified 3-CPD is not yet known and this review considers their likely metabolic fate in vivo. The latest developments in methods of analysis are presented while the occurrence of CPD esters and their potential formation mechanisms are discussed in detail. The generation of related compounds, possible measures of control and the future outlook are also considered.Practical application: Comprehensive and up to date information concerning the state of the art with respect to the occurrence of esters of chloropropanediols in foods presented all in one place. This concise review of toxicological aspects, methods of analysis, occurrence, formation routes and potential measures of control provides data for practical use by professionals engaged in research, surveillance, risk management and regulation of these contaminants in foods.