Occurrence of 3-chloropropane-1,2-diol and its esters in coffee

Fifteen coffee samples comprising green, roasted, decaffeinated and instant coffees were analysed for their content of free and bound 3-chloropropane-1,2-diol (3-MCPD). Green coffees contained only traces of the free 3-MCPD. 3-MCPD in roasted coffees was found at the level of 10.1–18.5 µg/kg. The highest 3-MCPD level of 18.5 µg/kg was found in one instant coffee sample and in coffees with very long time application during roasting. The final colour of the roasted coffee beans was directly linked to the 3-MCPD formed, the darker beans having the greatest concentration, and arabica coffees contained lower 3-MCPD levels than robusta coffees. The level of bound 3-MCPD varied between 6 µg/kg (soluble coffees) and 390 µg/kg (decaffeinated coffee) and exceeded the free 3-MCPD level 8–33 times. Arabica coffees contained higher levels of the bound 3-MCPD than robusta coffees. The recognised precursors of 3-MCPD (salt, glycerol, lipids) were also determined and their influence on the formation of the free and bound 3-MCPD was discussed.     

低含量3-氯-1,2-丙二醇的水解植物蛋白生产工艺优化

本文研究了在低酸、低温条件下植物蛋白的优化水解工艺，此工艺旨在降低水解蛋白中的氯丙醇类物质。研究确定：在98℃左右、固液比1：5、盐酸浓度4mol／L、水解18h所得水解蛋白中3-氯-1，2．丙二醇含量为1．25mg/kg，仅是常规酸法的5％。进一步进行碱中和与减压浓缩处理，可使3-氯-丙二醇残留大幅降低。     

Assessment of estimated daily intake of 3-monochloropropane-1,2-diol from soy sauce in Korea

Food Science and Biotechnology - Soy sauces collected from the Korean market were determined for 3-monochloropropane-1,2-diol (3-MCPD) and daily intake of 3-MCPD through the consumption of...     

食用植物油中脂肪酸氯丙醇酯形成机制的研究进展

脂肪酸氯丙醇酯的污染是近年来国际上新出现的热点食品安全问题之一,尤其是脂肪酸3-氯-1,2-丙二醇酯（3-chlorine-1,2-propylene glycol ester,3-MCPD酯）污染问题更为突出。研究表明,食用植物油中3-MCPD酯主要形成于精炼过程,而未精炼的食用植物油几乎不含3-MCPD酯。欧盟国家已对食用植物油中3-MCPD酯的形成机制开展了相关研究。本文主要对食用植物油种类、可能的前体物质、精炼工艺与3-MCPD酯形成的关系加以综述。     

Determination of 3-chloropropane-1,2-diol as its 1,3-dioxolane derivative at the μg kg-1 level: Application to a wide range of foods

This paper reports the application of a GC/MS method for the quantification of 3-chloropropane-1,2-diol (3-MCPD) at low µg kg^-1 levels through the determination of its 1,3-dioxolane derivative to a wide range of foodstuffs. The proposed protocol is based on the methods generally performed in control laboratories. The two main stages of the method — the solid-phase extraction and the purification of the derivatives — have been optimized. The within-laboratory reproducibility meets the official performance criteria for verifying 3-MCPD at the 20 µg kg^-1 limit stipulated by the European Community for soy sauce. The limit of quantification was below 5 µg kg^-1 for all the foodstuffs analysed. This method offers a valuable alternative to the draft CEN European Standard: instead of diethyl ether, much safer ethyl acetate is used; derivatization is more selective; and reagents are common stable chemicals. This method was successfully applied to toasted bread, savoury crackers, cheese, soups, including vegetable-based soups, meat products such as salami, vegetable oils, sauces, soy sauce and related products. Upon checking the method performance in the case of vegetable oils, the unexpected presence of monobromopropanediols was detected.     

Dietary exposure of Hong Kong adults to fatty acid esters of 3-monochloropropane-1,2-diol

A total of 290 individual food samples were collected in Hong Kong, China, for 3-monochloropropane-1,2-diol (3-MCPD) fatty acid esters analysis. Most samples were processed food and in ready-to-eat form. The results show that the levels of 3-MCPD fatty acid esters were high in biscuits, fats and oils, snacks and Chinese pastry with mean bound 3-MCPD levels of 440, 390, 270 and 270 μg kg^?1, respectively. The dietary exposures to bound 3-MCPD of average and high adult consumers were estimated to be 0.20 and 0.53 μg kg bw^?1 day^?1, respectively. The primary toxicological concern of 3-MCPD fatty acid esters is its potential to release 3-MCPD in vivo during digestion in the gastrointestinal tract. 3-MCPD would affect the kidney, the central nervous system and the male reproductive system of rats. Assuming that 100% of the 3-MCPD was released from 3-MCPD fatty acid esters by hydrolysis in the digestive system, the dietary exposures to 3-MCPD for average and high adult consumers were only 10% and 26% of the provisional maximum tolerable daily intake (PMTDI) of 3-MCPD established by the Joint Food and Agriculture Organization/World Health Organization Expert Committee on Food Additives (JECFA) (2 μg kg bw^?1 day^?1), respectively. The results suggest that both average and high adult consumers are unlikely to experience major toxicological effects of 3-MCPD.     

油脂微波加热模型中3-氯-1,2-丙二醇脂肪酸酯的形成

通过建立油脂微波加热模型,研究不同的油脂微波加热后3-氯-1,2-丙二醇（3-chloropropane-1,2-diol,3-MCPD）脂肪酸酯含量的变化情况以及NaCl溶液、pH值、时间、不连续微波和金属离子等因素对3-MCPD脂肪酸酯形成的影响。结果表明：1）熟榨植物油微波加热后3-MCPD脂肪酸酯含量增加均超过9 mg/kg,远超过其他植物油。2）3-MCPD脂肪酸酯含量随NaCl的质量浓度增加而增加,随NaCl溶液体积分数的增加呈先增加后减少趋势。3）酸性环境促进3-MCPD脂肪酸酯形成。4）微波加热10 min内,3-MCPD脂肪酸酯含量与时间呈正相关。5）微波总时间一定的情况下,不连续微波产生的3-MCPD脂肪酸酯明显少于连续微波。6）金属离子作为催化剂参与活性中间物的形成,能明显地促进3-MCPD脂肪酸酯的形成。上述结果可为食品微波加工处理过程中危害物3-MCPD脂肪酸酯的控制研究提供数据支持。     

3-Monochloropropane-1,2-diol fatty acid esters in commercial deep-fat fried foods

Levels of 3-monochloropropane-1,2-diol (3-MCPD) fatty acid esters were evaluated in commercial deep-fat fried foods from the Brazilian market using a GC-MS method preceded by acid-catalysed methanolysis. A limit of detection of 0.04 mg kg^?1, a limit of quantitation of 0.08 mg kg^?1, mean recoveries varying from 82% to 92%, and coefficients of variation ranging from 2.5% to 5.0% for repeatability and from 3.6% to 6.5% for within-laboratory reproducibility were obtained during in-house validation. The levels of the compounds in the evaluated samples, expressed as free 3-MCPD equivalent, ranged from not detected to 0.99 mg kg^?1, and the highest concentrations were observed in samples of chopped onion and garlic. A preliminary estimation of 3-MCPD intake using these occurrence data suggested low risks to human health, but a potential concern may arise in particular cases of consumers of fried food.     

甘油与氯化钠模型热反应中生成3-氯-1,2-丙二醇的研究

以甘油、氯化钠、水为原料建立热反应模型,结合气相色谱-质谱法（gas chromatography-mass spectrometry,GC-MS）分析,对其生成的3-氯-1,2-丙二醇（3-MCPD）进行了研究。通过正交实验,考察了反应时间、温度和各原料用量对3-MCPD生成量的影响,同时研究了在热反应模型中分别加入不同种类单糖和氨基酸后3-MCPD生成量的变化规律,并对其反应机理进行了探讨。结果表明,反应时间2h、反应温度140℃、甘油用量0.05g（占原料总量0.31%）、NaCl用量1.0g（6.23%）、水用量15g（93.46%）,3-MCPD生成量最少;葡萄糖、果糖、木糖、甘露糖、半乳糖、缬氨酸、精氨酸、赖氨酸、丝氨酸、亮氨酸、苯丙氨酸、苏氨酸、组氨酸使3-MCPD的生成量减少;谷氨酸、蛋氨酸、丙氨酸、天冬氨酸、甘氨酸使3-MCPD的生成量增加;半胱氨酸、酪氨酸、脯氨酸、色氨酸对3-MCPD的生成无明显作用。      

Occurrence of bound 3-monochloropropan-1,2-diol content in commonly consumed foods in Hong Kong analysed by enzymatic hydrolysis and GC-MS detection

The aim of this study was to determine the level of bound 3-monochloropropan-1,2-diol in foodstuffs commonly consumed in Hong Kong, China, by an enzymatic hydrolysis indirect method which proved to be free from interferences. A total of 290 samples were picked up randomly from the local market and analysed. About 73% of these samples were found to contain detectable amounts of bound 3-MCPD. Amongst the 73 food items, bound 3-MCPD was not detected in 13 food items, including extra virgin olive oil, beef ball/salami, beef flank, ham/Chinese ham, nuts, seeds, soy sauce, oyster sauce, butter, yoghurt, cream, cheese and milk. For those found to contain detectable bound 3-MCPD, the content ranged up to 2500 µg kg^?1. The highest mean bound 3-MCPD content among the 14 food groups was in biscuits (440 [50–860] µg kg^?1), followed by fats and oils (390 [n.d.–2500] µg kg^?1), snacks (270 [9–1000] µg kg^?1), and Chinese pastry (270 [n.d.–1200] µg kg^?1). Among the samples, the highest bound 3-MCPD content was in a grape seed oil (2500 µg kg^?1), followed by a walnut flaky pastry (1200 µg kg^?1) and a grilled corn (1000 µg kg^?1). Basically, the results of this study agreed well with other published results in peer-reviewed journals, except for cheese, cream, ham, nuts and seeds.     

Toxicological assessment of 3-monochloropropane-1,2-diol (3-MCPD) as a main contaminant of foodstuff in three different in vitro models: Involvement of oxidative stress and cell death signaling pathway

3-Monochloropropane-1,2-diol (3-MCPD) as a main source of food contamination has always been known as a carcinogenic agent. Kidney, liver, testis, and heart seem to be the main target organs for 3-MCPD. Because oxidative stress and mitochondrial dysfunction have been realized to be involved in 3-MCPD-induced cytotoxicity, the present study aimed to investigate the probable toxicity mechanisms of 3-MCPD in isolated mitochondria, HEK-293 cell line, and cell isolated from the rats’ liver and kidney through measuring multiparametric oxidative stress assay. Based on the data indicating no significant difference between 3-MCPD-treated groups and control group, metabolites of 3-MCPD have a key role in organ toxicity caused by them. To further investigating the suggested hypothesis, the effect of 3-MCPD toxicity on HEK-293 cell line was examined. Although the proliferation declined after exposure to a low dose of 3-MCPD (10 to 200 µM), controversial responses in higher concentration (2 to 10 mM) have led to studies on the effect of oxidative stress and cell death signaling on isolated kidney and liver cells. Treatment of the isolated kidney and liver cells with 3-MCPD resulted in an increase in the level of reactive oxygen species (ROS), the collapse of mitochondrial membrane potential (MMP), and activation of cell death signaling without creating any significant difference in the amount of reduced glutathione. In fact, 3-MCPD can disrupt the mitochondrial electron transfer in isolated cells, which is correlated with the impairment of mitochondrial oxidative phosphorylation system, the rise of ROS level, and the failure of MMP, leading to the release of cytochrome c from mitochondria to cytosol and finally the activation of cell death signaling.     

Updated occurrence of 3-monochloropropane-1,2-diol esters (3-MCPD) and glycidyl esters in infant formulas purchased in the United States between 2017 and 2019

ABSTRACT

Fatty acid esters of 3-monochloropropane-1,2-diol (3-MCPD) and glycidol are potentially carcinogenic and/or genotoxic processing contaminants that are formed during the process of edible oil refining. Because of their toxicological properties, the presence of these compounds in refined oils and foods containing these oils, particularly infant formula, poses a potential food safety concern. For this reason, recent research efforts have focussed on the development of methods for the analysis of MCPD and glycidyl esters in infant formula in order to estimate levels of exposure. This work presents occurrence data for 3-MCPD and glycidyl esters in 222 infant formulas purchased in the United States between December 2017 and January 2019. The results of this study show a wide range of contaminant concentrations across four different manufacturers, with average bound 3-MCPD concentrations ranging from 0.035 µg g^?1 to 0.63 µg g^?1 and average bound glycidol concentrations ranging from 0.019 µg g^?1 to 0.22 µg g^?1. The data suggest that manufacturers B and C source palm oil produced with mitigation measures, leading to reduced amounts of 3-MCPD and glycidyl esters in their infant formulas. Additionally, comparison with a previously published study in our laboratory of the occurrence of 3-MCPD and glycidyl esters in infant formula purchased in the U.S. between 2013 and 2016 revealed that, since 2016, contaminant concentrations have decreased in products produced by manufacturers A, B, and C, while contaminant amounts in formulas from manufacturer D have slightly increased.     

食品污染物3-氯-1,2-丙二醇毒理作用的研究进展

氯丙醇类化合物3-氯-1,2-丙二醇（3-MCPD）是目前国际上广为关注的食品污染物,最初发现在酸水解植物蛋白加工而成的食品中。近年来,许多食品特别是精制油中发现大量3-MCPD脂类,其能够在体内通过代谢途径产生3-MCPD。研究发现3-MCPD在啮齿类动物中存在明显的毒性作用,且具有种属和位点特异性。结合国内外毒理学研究成果,概述3-MCPD体内代谢途径,详细综述其急性毒理、致癌性以及遗传、生殖、免疫、神经毒性机制的研究进展,并展望了3-MCPD毒理学评价进一步研究的方向。      

Occurrence of Listeria monocytogenes in fresh and processed foods in Navarra (Spain)

The presence of Listeria spp. was investigated in a total of 3685 food samples obtained from different industries and markets of Northern Spain in the last 4 years. The samples analyzed include fresh raw products (meat, milk and poultry) and treated products (cooked and cured meats, frozen vegetables and smoked salmon). Occurrence of Listeria spp. varied from 8.1% in soft cheese to 76.3% in raw poultry samples. The highest incidence of L. monocytogenes also occurred in raw poultry (36.1% positive samples). Despite this high incidence of contamination, these kinds of products carry a low risk of listeriosis transmission because of the heat treatment prior to consumption. On the other hand, the ready-to-eat products (RTE) tested in this study showed incidences that could pose serious health problems, taking into account that the storage conditions may allow for rapid growth of the pathogen. It was also found that up to 75.5% of the L. monocytogenes strains isolated in this study belonged to serogroup 1, mainly serotype 1/2a, while the clinical cases observed in Navarra in the same period of time belonged mainly to serotype 4b/4bx.     

我国市酱油氯丙醇污染调查研究:3-氯-1,2-丙二醇(3-MCPD)与某些因素的关系

调查了我国市售酱油氯丙醇的污染情况,样品来自2003年全国污染物监测网和2004年卫生部健康相关产品卫生抽检。采用基质固相分散萃取法(MSPD)进行样品的净化,以稳定性同位素稀释技术结合气相-质谱法(GC-MS)的内标法定量测定3-氯-1,2-丙二醇(3-MCPD)含量。对3-MCPD污染水平与某些因素的关系作了探讨,结果表明,国家免检、HACCP认证、包装形式等因素与3-MCPD水平有显著性相关关系(P<0.05),而QS认证、IS09000认证、推荐与监制、铁强化、生产工艺、质量等级和抽样场所等因素与3-MCPD水平的高低没有显著性关系(P>0.05),说明QS认证、IS09000认证、推荐与监制等措施对氯丙醇降低的作用不明显。此外,来自餐饮业酱油的氯丙醇污染相对较高,值得进一步关注。     

Occurrence of 3-MCPD fatty acid esters in human breast milk

A series of twelve breast milk samples were analysed by gas chromatography-mass spectrometry (GC/MS) operated in selected ion monitoring mode for 3-chloropropane-1,2-diol (3-MCPD). Whilst none of the samples contained 3-MCPD above the limit of detection of 3 μg kg^?1 milk, all contained high amounts of 3-MCPD esterified with higher fatty acids. The levels of 3-MCPD released by hydrolysis of these esters (bound 3-MCPD) ranged from the limit of detection (300 μg kg^?1, expressed on a fat basis) to 2195 μg kg^?1; with a mean level of bound 3-MCPD of 1014 μg kg^?1, which corresponded to 35.5 μg kg^?1 milk. The presence of bound 3-MCPD was confirmed using orthogonal gas chromatography coupled with high-speed time-of-flight mass spectrometry analysis for four randomly selected breast milk samples. Six breast milks collected from one of the nursing mothers 14–76 days after childbirth contained bound 3-MCPD within the range of 328–2078 μg kg^?1 fat (mean 930 μg kg^?1 fat). The calculated bound 3-MCPD content of these samples was within the range of 6 and 19 μg kg^?1 milk (mean of 12 μg kg^?1 milk). The major types of 3-MCPD esters were the symmetric diesters with lauric, palmitic, and oleic acids, and asymmetric diesters with palmitic acid/oleic acid among which 3-chloro-1,2-propanediol 1,2-dioleate prevailed.     

Toxicological assessment of 3-chloropropane-1,2-diol and glycidol fatty acid esters in food

Fatty acid esters of 3‐chloropropane‐1,2‐diol (3‐MCPD) and glycidol are a newly identified class of food process contaminants. They are widespread in refined vegetable oils and fats and have been detected in vegetable fat‐containing products, including infant formulas. There are no toxicological data available yet on the 3‐MCPD and glycidol esters, and the primary toxicological concern is based on the potential release of 3‐MCPD or glycidol from the parent esters by lipase‐catalyzed hydrolysis in the gastrointestinal tract. Although 3‐MCPD is assessed as a nongenotoxic carcinogen with a tolerable daily intake (TDI) of 2 μg/kg body weight (bw), glycidol is a known genotoxic carcinogen, which induces tumors in numerous organs of rodents. The initial exposure estimates, conducted by Federal Institute for Risk Assessment (BfR) under the assumption that 100% of the 3‐MPCD and glycidol are released from their esters, revealed especially that infants being fed commercial infant formula could ingest harmful amounts of 3‐MCPD and glycidol. However, the real oral bioavailability may be lower. As this gives rise for toxicological concern, the currently available toxicological data of 3‐MCPD and glycidol and their esters are summarized in this review and discussed with regard to data gaps and further research needs.     

3-Monochloropropane-1,2-diol (3-MCPD) in soy sauces and similar products available from retail outlets in the UK

A survey of the level of 3-monochloropropane-1,2-diol (3-MCPD) in soy sauces and similar products available in the UK is reported. The survey was carried out by the Joint Ministry of Agriculture, Fisheries and Food/Department of Health Food Safety and Standards Group (JFSSG) to check for compliance with the Food Advisory Committee's (FAC) recommended limit for 3-MCPD of 0.01mg/kg following reports that soy sauces in several European countries had been found to contain high levels (up to 124mg/kg) of 3-MCPD. Forty samples of soy sauce and similar products purchased from retail outlets were analysed using a GC-MS procedure which had been formally validated by an earlier collaborative trial. 3-MCPD was undetectable in 21 (52%) of samples analysed in the survey, with a further five samples containing very low levels of between 0.01 and 0.02mg/kg. Five samples (13%) contained 3-MCPD at levels in the range 0.020-1mg/kg while nine samples (23%) were found to contain 3-MCPD at levels greater than 1mg/kg, with the highest level being 30.5mg/kg.     

Kinetics of 3-chloropropane-1,2-diol (3-MCPD) degradation in high temperature model systems

A study of the decay kinetics of 3-chloropropane-1,2-diol (3-MCPD) at high temperatures in aqueous model systems is reported. Data obtained over the pH range 5-6.5 and temperatures of 80-142 °C agreed well with a predicative model derived from earlier kinetic data. The results showed that 3-MCPD was unstable in aqueous solutions approaching infinite dilution at temperatures above 80 °C. Comparison of the experimental decay of 3-MCPD with that based on the kinetic parameters A (=10^{7.73347+0.83775pH}s-1) and E_a (=119.2 kJ mol^-1) was good to within 20% over the temperature and pH ranged studied. A putative mechanism for the degradation reaction is discussed together with the implications for the decay and formation of 3-MCPD in food systems.     

橄榄二酯油烘焙苏打饼干中3-氯丙醇酯、缩水甘油酯产生规律及其质构分析

以橄榄甘油二酯油为原料,制作苏打饼干,考察甘油二酯（diglycerides,DAG）含量、烘焙温度、盐添加量、烘焙时间对饼干中3-氯丙醇酯（3-monochloropropane-1,2-diol esters,3-MCPDE）和缩水甘油酯（glycidyl esters,GE）及饼干硬度和黏度的影响。结果表明,苏打饼干中3-MCPDE和GE的最高含量分别为1.05 mg/kg和0.37 mg/kg,且烘焙过程中3-MCPDE含量与烘焙温度和盐添加量呈正相关,在170℃以上时GE含量随烘焙温度升高而增加。但烘焙时间和DAG质量分数对3-MCPDE和GE的产生无显著影响（P>0.05）。综上,橄榄甘油二酯油应用于烘焙苏打饼干具有良好的安全性和改善产品质构的效果,同时控制烘焙温度和盐添加量能在一定程度降低苏打饼干中3-MCPDE和GE的含量。