Monitoring and risk assessment of 74 pesticide residues in Pu-erh tea produced in Yunnan, China

Simultaneous Determination of Pesticide Residues and Mycotoxins in Storage Pu-erh Tea Using Ultra-High-Performance Liquid Chromatography Coupled with Tandem Mass Spectrometry

Mycotoxins and pesticides are the most concerning chemical contaminants that can affect the quality of Pu-erh tea during its production and storage. This study presents a method that can simultaneously determine 31 pesticide residues and six mycotoxins in Pu-erh tea within 11 min using ultra-high-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS) after QuEChERS extraction. The lower limit of quantification (LOQ) for all analytes ranged between 0.06 and 50 ppb. Recoveries for each pesticide and mycotoxin ranged between 62.0 and 130.3%, with intra- and inter-day precisions lower than 15%. Good linear relationships were obtained, with correlation coefficients of r2 > 0.991 for all analytes. The established method was applied to 31 Pu-erh tea samples, including raw and ripened Pu-erh tea with different storage times. As a result, pesticide residues were not detected in any of the collected samples, and the mycotoxins detected in the samples were well below the official maximum residue limits (MRLs). Notably, the levels of aflatoxin B1 (AFB1), aflatoxin G1 (AFG1) and aflatoxin G2 (AFG2) were lower than 1 ppb in the samples stored for more than 30 years.

Pesticides, trace elements and pharmaceuticals in tea samples available in Belgian retail shops and the risk associated upon acute and chronic exposure

Over the last decade, the consumption of tea and herbal tea has gained more and more popularity across the globe, but the potential presence of chemical contaminants (e.g. pesticides, trace elements, synthetic drugs) may raise health concerns. This study analysed selected teas available in Belgian retail stores and performed a risk assessment for these samples. No chemical adulteration could be detected in dry tea material. More than 38% of the dry leaves samples contained at least one pesticide exceeding the maximal residue level (MRL) set by the EU. However, further risk assessment, based on the values of pesticide residues and the toxic trace elements encountered in the brew, demonstrate that the consumption of these teas will not give rise to health concerns. Nonetheless, attention should be given to the leaching potential of nickel from teas and the presence of arsenic in brews from algae containing teas.

Occurrence and exposure risk assessment of pesticide residues in green tea samples cultivated in Hangzhou area, China

The concentration of pesticide residues in 105 green tea samples grown in Hangzhou area were investigated. Of the 14 pesticides analysed using gas chromatography-tandem mass spectrometry and the 27 pesticides analysed using liquid chromatography-tandem mass spectrometry, only 18 were detected in the tea samples. The most frequently detected pesticide residues were imidacloprid (35.2%), acetamiprid (26.7%), carbendazim (21.0%), bifenthrin (21.0%), and cyhalothrin (19.1%). Carbofuran was the only pesticide which exceeded in one sample the maximum residue limit. The concentrations of the analytes in tea samples ranged from below the limit of detection (LOD) to 2.64 mg/kg. Their mean concentrations were all below the LOD, except for imidacloprid, acetamiprid, carbendazim, bifenthrin and cyhalothrin. Based on a preliminary long-term exposure assessment, the hazard quotient values of the detected pesticides varied in the range 0.47 × 10^-3 - 1.1 × 10^-3%, which indicates that these levels did not pose a risk to human health in Hangzhou area.

Application of BRAFO-tiered approach for health benefit-risk assessment of dark tea consumption in China

Dark tea, a unique tea fermented primarily in China, has numerous potential beneficial effects. However, harmful substances present in dark tea have provoked significant concern. To conduct a quantitative benefit-risk assessment of dark tea for Chinese residents and provide guidance on rational consumption, a framework of Benefit-Risk Analysis for Foods (BRAFO) and meta-analysis was applied to construct a disability-adjusted life year (DALY). Based on the BRAFO-tiered approach, a reference scenario (no intake) and an alternative scenario (intake of 3 cups/day) were determined. The overall health impacts of dark tea were simulated by comparing the risks of fluoride and AF with benefits of reduced-risk to coronary heart disease (CHD) and diabetes in different scenarios. Three cups of fermented tea consumed per day decreased risks of CHD and diabetes by 8.16% and 12.77% respectively. After quantitative integration of information, the ultimate net health effect was found to be -1958.827 illustrating that the benefits of drinking three cups of dark tea per day outweigh the risks. However, considering the uncertainties in the process, decision-makers should proceed with caution, consulting additional well-conducted studies and further managing harmful substances in dark tea.

Pesticide residues and health risk appraisal of tomato cultivated in greenhouse from the Mediterranean region of Turkey

This research aims at assessing the health risks associated with pesticide residues in greenhouse grown tomato production in the Mediterranean Region of Turkey. A multiresidue method based on modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) was used for sample preparation that is applied for pesticide detection from extraction of tomato samples in the methodology generated by The Association of Official Analytical Chemists (AOAC) Official Method. The restrain of the quantification varied from 0.002 to 0.009 mg kg-1. The validated data exposed both adequate recoveries, repeatability and reproducibility, including accomplished all other requirements of the European DG SANTE/12682/2019 Guideline. This study divulges that tomatoes cultivated in greenhouse demonstrate 61.5% of samples with one or various pesticide residues. The maximum permitted residue level of above the EU DG Guideline was in 12.2% of the samples. The main determined pesticide residues on the tomatoes cultivated in greenhouse were identified as chlorpyrifos methyl, cyfluthrin, deltamethrin, and acetamiprid. Chlorpyrifos methyl (9.5%), cyfluthrin (6.6%), deltamethrin (5.5%), and acetamiprid (3.2%) were recognized as the most conducing residues to the hazard index (HI). The HI was 9.5% for adults and 11.02% for children (3 to <10 years). The major contributor of the HI was chlorpyrifos in both.

Three widely used pesticides and their mixtures induced cytotoxicity and apoptosis through the ROS-related caspase pathway in HepG2 cells

Difenoconazole, cypermethrin and triazophos are widely used pesticides in agricultural production and frequently detected in foods. The aim of this study was to determine the effect of these pesticides and their mixtures on cell viability, reactive oxygen species (ROS), lactate dehydrogenase (LDH) content, apoptosis rate and DNA fragmentation and synthesis in human hepatocellular carcinoma cells (HepG2). The order of inhibitory effects for the individual pesticides was ranked as difenoconazole > cypermethrin > triazophos. The enhanced expression of caspase-3, caspase-7 and PARP activity was observed in HepG2 cells, which was 1.7, 1.3 and 1.6-fold higher than the control, respectively, along with significant protein cleavage; and induced apoptosis in a concentration-dependent manner. Further, the pesticide mixtures significantly increased ROS level (up to 1.3-fold), induced DNA fragmentation (up to 1.8-fold), inhibited DNA synthesis (up to 53%), and damaged the cells by destroying the cell membrane and producing a large amount of LDH at concentration range of 10-30 μM. Specifically, mixtures containing difenoconazole showed stronger toxicities than individual pesticides, implying higher health risks associated with mixtures. Our results show that three widely used pesticides exhibited cytotoxicity and apoptosis through the ROS-related caspase pathway, providing a basis for evaluation of health risks from pesticide mixtures via food consumption.

Systematic probabilistic risk assessment of pesticide residues in tea leaves

Multiple pesticide residues are frequently present in tea leaves and while the majority of residues satisfy Taiwan's current health regulations, there are potential health effects from pesticide exposure that are of great concern for tea drinkers. We undertook a systematic probabilistic risk assessment of 59 pesticides in tea leaves from 1629 tea leaf samples obtained by Taiwan's Food and Drug Administration in two monitoring surveys in 2015. Bayesian statistics used a Markov Chain Monte Carlo approach to estimate posterior distributions of pesticide residues in tea leaves, lifetime average daily doses and hazard quotients (HQs) of evaluated pesticides. We classified 95th percentile values of HQs into three categories: 0 < HQ < 0.5, 0.5 ≤ HQ ≤ 1 and 1 < HQ. The 95th percentiles of HQs for triazophos (3.39), carbofuran (2.04) and endosulfan (1.80) exceeded 1 in the adult population; the HQ for 3-OH carbofuran was 0.97 and was less than 0.5 for the remaining 55 pesticides. The health risk posed by pesticide residues for tea drinkers is negligible, if triazophos, carbofuran, endosulfan, and 3-OH carbofuran residues satisfy regulatory standards. However, five legacy pesticides, DDT, methomyl, carbofuran, dicofol and endosulfan, were identified. To reduce uncertainties, this study combined Bayesian statistics with a mode of action approach for systematic risk assessment of co-exposure to multiple pesticide residues in tea leaf samples. Measuring pesticide transfer rates will improve the quality of future risk assessments concerning residues in tea leaves. Appropriate management of pesticides in Taiwanese tea farms and monitoring of pesticide residues in imported tea is warranted to protect Taiwan's tea drinkers.

Residual behavior and risk assessment of butralin in peanut fields

Butralin is widely used to control single-leaf weeds and some dicotyledons. The application of butralin in the environment may cause residue beyond regulation criteria and residual toxicity. Therefore, it is important to detect and supervise the dissipation behavior of butralin in edible raw food and in the environment. The aim of this study was to monitor butralin in peanuts and soil under farmland conditions and examine the likely dietary risk assessment of butralin for Chinese people on the basis of residual concentrations. A method for the analysis of butralin residue and its dissipation in peanut plants and soil under field conditions was investigated. The results show that an analytical method for the quantization of butralin in peanuts and soil utilizing gas chromatography with electron capture detection (GC-ECD) was developed. Standard recovery experiments using three different butralin spiking levels of 0.01, 0.1, and 1.0 mg kg^-1 in different samples (i.e., peanut kernels, shell, seedling, stalk, and soil) were conducted. The recoveries of butralin from all matrices ranged from 86 to 108% with relative standard deviations from 3 to 6% (n = 5). The limit of quantification (LOQ) of the method was 0.01 mg kg^-1. After storage at - 20 °C for 365 days, the degradation rate of residues of butralin in peanut kernels was less than 30%, which met the storage stability test criteria for pesticide residues in stored commodities of plant origin. The dissipation half-lives of butralin ranged from 4.2 to 6.6 days and 4.6 to 6.6 days in peanut seedlings and soil, respectively, in farmland ecosystems. At the normal harvest time, the final residue concentrations of butralin in peanuts and soil were all below the LOQ. The final total risk quotient (RQ) values were much lower than RQ = 100%, which indicated that the long-run fitness risk associated with butralin residue in different groups of registered crops is correspondingly low for people in China. The current research results could offer guidance for the rational use of butralin and provide data support for the building of maximum residue limits (MRLs) in China.

Health Functions and Related Molecular Mechanisms of Tea Components: An Update Review

Tea is widely consumed all over the world. Generally, tea is divided into six categories: White, green, yellow, oolong, black, and dark teas, based on the fermentation degree. Tea contains abundant phytochemicals, such as polyphenols, pigments, polysaccharides, alkaloids, free amino acids, and saponins. However, the bioavailability of tea phytochemicals is relatively low. Thus, some novel technologies like nanotechnology have been developed to improve the bioavailability of tea bioactive components and consequently enhance the bioactivity. So far, many studies have demonstrated that tea shows various health functions, such as antioxidant, anti-inflammatory, immuno-regulatory, anticancer, cardiovascular-protective, anti-diabetic, anti-obesity, and hepato-protective effects. Moreover, it is also considered that drinking tea is safe to humans, since reports about the severe adverse effects of tea consumption are rare. In order to provide a better understanding of tea and its health potential, this review summarizes and discusses recent literature on the bioactive components, bioavailability, health functions, and safety issues of tea, with special attention paid to the related molecular mechanisms of tea health functions.