Occurrence of Ethyl Carbamate in Foods and Beverages: Review of the Formation Mechanisms, Advances in Analytical Methods, and Mitigation Strategies

ABSTRACT

Ethyl carbamate (EC) is a process contaminant that can be formed as a by-product during fermentation and processing of foods and beverages. Elevated EC concentrations are primarily associated with distilled spirits, but this compound has also been found at lower concentrations in foods and beverages, including breads, soy sauce, and wine. Evidence from animal studies suggests that EC is a probable human carcinogen. Consequently, several governmental institutions have established allowable limits for EC in the food supply. This review includes EC formation mechanisms, occurrence of EC in the food supply, and EC dietary exposure assessments. Current analytical methods used to detect EC will be covered, in addition to emerging technologies, such as nanosensors and surface-enhanced Raman spectroscopy. Various mitigation methods have been used to maintain EC concentrations below allowable limits, including distillation, enzymatic treatments, and genetic engineering of yeast. More research in this field is needed to refine mitigation strategies and develop methods to rapidly detect EC in the food supply.

HIGHLIGHTS

Acrylamide in non-centrifugal sugar from Latin American markets: in-house validation of an LC-MS/MS method, dietary exposure assessment and risk characterisation in Brazil and Colombia

A liquid chromatography tandem mass spectrometry method (LC-MS/MS) preceded by a rapid and simple QuEChERS-based sample preparation was developed and validated for the determination of acrylamide in non-centrifugal sugar (NCS), a solid product obtained from sugarcane juice without centrifugation, up to a concentration greater than 90 ºBrix. Adequate linearity in calibration curves, analytical selectivity and sensitivity were achieved. A limit of detection (LOD) and a limit of quantitation (LOQ) of 10 and 20 µg kg^-1, respectively, were obtained. Recoveries (84.3-107.5%) and coefficients of variation (CV<15%) for repeatability and reproducibility conditions were appropriate in intraday and interday laboratory conditions. The concentration of acrylamide was determined in 76 commercial samples of NCS from different Latin American countries and ranged from <20 to 1414 µg kg^-1. The highest mean acrylamide amounts were found in samples from Peru, Ecuador and Colombia (636, 446 and 401 µg kg^-1, respectively). Considering the form of the product, the highest average levels were found in granulated NCS (517 µg kg^-1) when compared to block (294 µg kg^-1). Within the Colombian samples, organic NCS, made with natural flocculant, presented a higher acrylamide mean concentration (721 µg kg^-1) than conventional samples (363 µg kg^-1). Although the Margin of Exposure (MOE) values for neurotoxicity suggested that the estimated intakes in Brazil and Colombia are not a concern, MOEs obtained for neoplastic effects raised attention.

Effects of variety and nutrient availability on the acrylamide-forming potential of rye grain

Acrylamide is a probable human carcinogen that forms in plant-derived foods when free asparagine and reducing sugars react at high temperatures. The identification of rye varieties with low acrylamide-forming potential or agronomic conditions that produce raw material with low acrylamide precursor concentrations would reduce the acrylamide formed in baked rye foods without the need for additives or potentially costly changes to processes. This work compared five commercial rye varieties grown under a range of fertilisation regimes to investigate the effects of genotype and nutrient (nitrogen and sulphur) availability on the accumulation of acrylamide precursors. A strong correlation was established between the free asparagine concentration of grain and the acrylamide formed upon heating. The five rye varieties accumulated different concentrations of free asparagine in the grain, indicating that there is genetic control of this trait and that variety selection could be useful in reducing acrylamide levels in rye products. High levels of nitrogen fertilisation were found to increase the accumulation of free asparagine, showing that excessive nitrogen application should be avoided in order not to exacerbate the problem of acrylamide formation. This effect of nitrogen was mitigated in two of the varieties by the application of sulphur.