Polychlorinated dibenzo-p-dioxins and dibenzofurans formed from sucralose at high temperatures

Levels, enrichment characteristics and dietary intake risk of polychlorinated dibenzo-p-dioxin/furans in traditional smoked pork

The concentrations and TEQs of polychlorinated dibenzo-p-dioxin/furans (PCDD/Fs) in traditional smoked pork were significantly higher than those in raw pork, and mainly distributed in the surface layer. The main enriched congeners during traditional smoking were 2378-TCDF, 12378-PeCDF, 23478-PeCDF, 1234678-HpCDF, OCDF, 1234678-HpCDD and OCDD. The ability of each congener to transfer from the surface to the inner part was various. According to the dietary habits of local residents, PCDD/Fs in more than half of the traditional smoked pork samples posed a potential carcinogenic risk, and the risk in the surface samples were 1.02-10.2 times that of the corresponding inner samples. Some variables might be the important factors affecting the concentration of PCDD/Fs in smoked pork, such as the duration of smoking and the kind of fuel. It is recommended to achieve lower risk by reducing the consumption of smoked pork, especially the surface layer of smoked pork, and innovating traditional smoking technologies.

Occurrence and source analysis of polychlorinated naphthalenes in raw cow milk

The potential contamination of food items with polychlorinated naphthalenes (PCNs) has attracted increasing attention because of their toxicity, persistence and bioaccumulative characteristics. Humans are exposed to PCNs primarily through consuming animal-derived foodstuffs. However, the pathways by which PCNs can enter the food supplying chain are poorly understood. In this study, Σ₇₅PCNs were determined in raw cow milk (n = 82) collected from three different regions that varied in the intensity of PCNs emission sources in North China, using high-resolution gas chromatography/high-resolution mass spectrometry method. Higher PCN concentrations (214-2050 pg/g lw) were found in raw cow milk from dairy cow farms located in the region with relatively higher intensity of emission sources. Less chlorinated congeners were dominant in all raw cow milk samples. PCNs in cow milk might result from industrial fly ash emissions that contaminate animal feed through atmospheric deposition. Risks posed to humans through consuming PCNs in cow milk were low.

Evaluation of analytical method for polycyclic aromatic hydrocarbons content in home meal replacement products by GC/MS

This study analyzed four polycyclic aromatic hydrocarbons (PAHs) from frequently consumed home meal replacement (HMR) products in Korea and evaluated their chemical analysis methods. The PAHs investigated were benzo[a]anthracene, chrysene, benzo[b]fluoranthene and benzo[a]pyrene. Chrysene-d12 and benzo[a]pyrene-d12 served as internal standards. The sample was dissolved in dichloromethane before extraction. Liquid-liquid extraction, microwave extraction, alkali digestion and GC-MS were used for analysis. Method validation was conducted on four matrices: fatty solid, fatty liquid, non-fatty liquid, non-fatty solid. Linear correlation coefficients (R2) were all above 0.99 and accuracy ranged from 80.03 to 119.65%. The LOD and LOQ were in the range of 0.03-0.15 and 0.09-0.44 μg/kg, respectively. The recoveries varied from 81.09 to 116.42% and precision ranged from 0.07 to 10.73% in both intraday and interday analysis. All concentrations of total PAHs from HMR products were detected at relatively low concentration. This study could provide the PAHs content from HMR products in Korea.

Use of sucralose in foods heated during manufacturing does not pose a risk to human health

Regulatory agencies around the world have found sucralose to be a safe ingredient for use in food. A recent review by the German Federal Institute for Risk Assessment (BfR) hypothesized that sucralose use in foods heated during their manufacture might pose a health risk, by resulting in the formation of certain chlorinated compounds; specifically, polychlorinated dibenzodioxins (PCDDs), polychlorinateddibenzofurans (PCDFs) and/or free or bound 3-monochloropropanediol (3-MCPD), some of which are considered potential carcinogens. The BfR further encouraged the European Food Safety Authority (EFSA), which is in the process of conducting a staged re-evaluation of a range of food additives, including sucralose, to specifically address their hypothesis. This paper reports the results of new studies requested by EFSA to analyze for the presence of PCDDs, PCDFs and 3-MCPDs in a range of foods. As requested, foods were prepared with typical sucralose use levels and thermally processed under typical food processing conditions. The presence of the compounds of interest were analyzed using validated and accepted analytical methods (e.g. US Environmental Protection Agency (EPA); American Oil Chemists Society (AOCS)). The results of these new analytical studies show no evidence for the formation of these compounds due to sucralose presence. This paper also reports a critical analysis of the studies cited in the BfR review as the basis for its hypothesis. This analysis shows that the cited studies do not represent food manufacturing conditions and are thus not reliable for predicting the fate of sucralose in foods. This work reaffirms that sucralose is safe for use in food manufacture, including when heating is required.

Estimation of Industrial Emissions during Pyrolysis and Combustion of Different Wastes Using Laboratory Data

In our lab, we have been studying the emissions of different pollutants during pyrolysis and combustion of wastes under different conditions for the last three decades. These studies have focused on the effect of temperature and presence of oxygen on the production of different pollutants. Waste decomposition has been studied in a horizontal laboratory scale reactor, but no estimate has been made of the actual emissions in a conventional thermal decomposition system. In the present study, emissions during these wastes' thermal decomposition were estimated using Aspen HYSYS. In the simulation software, the waste composition (elemental analysis) was given as an input parameter, as well as the gas flow rate used as atmosphere during the decomposition. The emitted hydrocarbons measured in the laboratory were equated to the emission of a single compound (propylene). The simulation permitted calculating the percentage of oxygen in the emitted gas, and the pollutant emissions were then recalculated under standard conditions. The emission of dioxins and furans were estimated under different conditions of decomposition, and an adequate approximation of the waste decomposition in actual incineration systems could be obtained.

Dehalogenases: From Improved Performance to Potential Microbial Dehalogenation Applications

The variety of halogenated substances and their derivatives widely used as pesticides, herbicides and other industrial products is of great concern due to the hazardous nature of these compounds owing to their toxicity, and persistent environmental pollution. Therefore, from the viewpoint of environmental technology, the need for environmentally relevant enzymes involved in biodegradation of these pollutants has received a great boost. One result of this great deal of attention has been the identification of environmentally relevant bacteria that produce hydrolytic dehalogenases—key enzymes which are considered cost-effective and eco-friendly in the removal and detoxification of these pollutants. These group of enzymes catalyzing the cleavage of the carbon-halogen bond of organohalogen compounds have potential applications in the chemical industry and bioremediation. The dehalogenases make use of fundamentally different strategies with a common mechanism to cleave carbon-halogen bonds whereby, an active-site carboxylate group attacks the substrate C atom bound to the halogen atom to form an ester intermediate and a halide ion with subsequent hydrolysis of the intermediate. Structurally, these dehalogenases have been characterized and shown to use substitution mechanisms that proceed via a covalent aspartyl intermediate. More so, the widest dehalogenation spectrum of electron acceptors tested with bacterial strains which could dehalogenate recalcitrant organohalides has further proven the versatility of bacterial dehalogenators to be considered when determining the fate of halogenated organics at contaminated sites. In this review, the general features of most widely studied bacterial dehalogenases, their structural properties, basis of the degradation of organohalides and their derivatives and how they have been improved for various applications is discussed.

Investigation of ozonation kinetics and transformation products of sucralose

Sucralose is one of widely used artificial sweeteners, which has been ubiquitously detected in various water sources, such as wastewater and randomly in reservoir water. It is also reported to be persistent to various water treatment techniques. Although there are some studies on removal of sucralose by advanced oxidation process, limited information, in terms of reaction kinetics, transformation products and degradation pathway etc., was reported in its ozonation process. In this study, the reaction kinetics, removal efficiency, influence of pH, humic acid and carbonate on sucralose degradation by ozone, have been studied systematically. The results demonstrated that ozonation of sucralose was initiated by the formation of OH radical. Sucralose could be completely removed with excess O₃ at neutral and basic conditions in ultrapure water. The rate of degradation decreased significantly in acidic condition and in the presence of carbonate and OH radical scavenger (e.g. tert-butanol). The acidity was the key factor affecting the degradation of sucralose. The rate constant was about 500 times higher at pH7 than that at pH4. Transformation products study indicated that the ozonation of sucralose were more complex than that in photolysis reaction. Although ozonation of sucralose was initiated by OH radical, both OH radical and O₃ might be involved in the formation of transformation products and total organic carbon (TOC) removal. Various transformation products, such as aldehydes, carboxylic acids and probable chloride containing products, were identified and characterized in details. An ozonation degradation pathway of sucralose was proposed as well.

Statement on the validity of the conclusions of a mouse carcinogenicity study on sucralose (E 955) performed by the Ramazzini Institute

The Panel on Food Additives and Nutrient Sources added to Food (ANS) was requested from the European Commission to provide a statement on the validity of the conclusions of a mouse study on the carcinogenic potential of sucralose (E 955) performed by the Ramazzini Institute (Soffritti et al., 2016). Sucralose (E 955) is authorised as a food additive in the EU in accordance with Annex II to Regulation (EC) No 1333/2008 on food additives. According to Commission Regulation (EU) No 257/2010, the full re-evaluation of sucralose shall be completed by December 2020. Taking into consideration the publication from Soffritti et al. (2016), the technical report and additional information provided by the Ramazzini Institute and other information available for sucralose (E 955), the Panel noted: (i) the design of the bioassay that considers exposure from gestation up to natural death of animals implies an increase in background pathology that results in the possibility of misclassifications and a difficult interpretation of data, especially in the absence of both an appropriate concurrent control group and a recent historical database; (ii) the lack of a dose-response relationship between the exposure to sucralose and incidence of lymphomas and leukaemias (combined); (iii) the lack of a mode of action and failure to meet all the Bradford-Hill considerations for a cause-effect relationship between intake of sucralose and the development of tumours in male mice only; (iv) a comprehensive database was available for sucralose and no carcinogenic effect was reported in adequate studies in rats and mice. Moreover, there was no reliable evidence of in vivo genotoxicity. Therefore, the Panel concluded that the available data did not support the conclusions of the authors (Soffritti et al., 2016) that sucralose induced haematopoietic neoplasias in male Swiss mice.

Thermal degradation of sucralose: a combination of analytical methods to determine stability and chlorinated byproducts

In the late years, much attention has been brought to the scientific community regarding the safety of sucralose and its industrial applications. Although it is the most used artificial sweetener in foods and pharmaceuticals, many questions still arise on its potential to form chlorinated byproducts in high temperatures, as demonstrated by several recent studies. In the present contribution, we use a combination of differential scanning calorimetry and thermogravimetric analysis coupled with infrared spectroscopy (DSC/TGA/IR), Hot-stage microscopy (HSM) and high-resolution mass spectrometry (HRMS) on samples submitted to water bath at mild temperatures to evaluate a broad spectrum of hazardous compounds formed in the degradation of this product. TGA/IR has revealed that there is effective decomposition in form of CO₂ along with the formation of hydrogen chloride and other minor compounds. HSM results have provided accurate information, where the melting of the crystals was observed, followed by decomposition. Chlorinated derivatives, including polychlorinated aromatic hydrocarbons (PCAHs) were also confirmed by HRMS. These findings not only corroborate the suspected instability of sucralose to high temperatures, but also indicate that even exposed to mild conditions the formation of hazardous polychlorinated compounds is observed.