How manufacturing processes affect the level of pesticide residues in tea

Article (PDF Available)inJournal of the Science of Food and Agriculture 84(15):2123 - 2127 · December 2004with236 Reads
DOI: 10.1002/jsfa.1774
Abstract
Tea (both green and black) is consumed throughout the world, both for pleasure and therapeutic purposes. Most people will be unaware of their involuntary exposure to residues of pesticides lingering in processed tea and so possibly transferring into infusions of tea. The purpose of this work was to study the effect of green tea and orthodox black tea manufacturing processes on the fate of pesticides sprayed onto tea bushes (Camellia sinensis). The fates of residues of dimethoate, quinalphos, dicofol and deltamethrin in these two different types of tea manufacturing processes were compared. For black tea, the manufacturing process involves leaf harvesting, withering, rolling, fermentation and drying; and for green tea, leaf harvesting, microwave heating, rolling and drying. The two processes resulted in the same concentration factor of plant material into the dried commodity, while the decreases in residue levels were different for different pesticides. Initial microwave heating and dehydration in the green tea manufacturing process resulted in greater loss of pesticide residues than did withering and dehydration in black tea; no significant reduction in residue level resulted from the rolling and fermentation steps in black tea. Residue levels in both green and black teas were reduced during final drying. Copyright © 2004 Society of Chemical Industry
    • "September 25, 2015(8–13%) and imidacloprid (9–13%) were quite significant during drying among all steps in black tea manufacturing. The loss of residue would mainly attribute to factors of degradation, evaporation, and co-distillation [22]. PF ratio of dimethoate and dry matter concentration after withering (0.74–0.77) was much lower than spreading (0.90–0.92), indicating larger loss of dimethoate was occurred during withering than spreading. "
    [Show abstract] [Hide abstract] ABSTRACT: Residue levels of dimethoate and its oxon metabolite (omethoate) during tea planting, manufacturing, and brewing were investigated using a modified QuEChERS sample preparation and gas chromatography. Dissipation of dimethoate and its metabolite in tea plantation followed the first-order kinetic with a half-life of 1.08-1.27 d. Tea manufacturing has positive effects on dimethoate dissipation. Processing factors of dimethoate are in the range of 2.11-2.41 and 1.41-1.70 during green tea and black tea manufacturing, respectively. Omethoate underwent generation as well as dissipation during tea manufacturing. Sum of dimethoate and omethoate led to a large portion of 80.5-84.9% transferring into tea infusion. Results of safety evaluation indicated that omethoate could bring higher human health risk than dimethoate due to its higher hazard quotient by drinking tea. These results would provide information for the establishment of maximum residue limit and instruction for the application of dimethoate formulation on tea crop.
    Full-text · Article · Sep 2015
    • "In 2009, Canada alone had an annual per capita consumption of 77 l (Statistics Canada, 2009). Tea producers often use pesticides, such as insecticides and fungicides to protect crops from devastating insect and disease infestation (Sood et al., 2004). There is evidence that some teas contain detectable pesticide residues, including organochlorines (OC) and organophosphates (OP) (Canadian Food Inspection Agency (2010–2011; Wang et al., 2014 ).; Current Canadian prenatal nutrition guidelines (Public Canada, 2014) include caffeine content and medicinal properties that may lead to adverse health benefits but do not consider pesticide concentrations in the tea. "
    [Show abstract] [Hide abstract] ABSTRACT: Pesticide residues in tea may contribute to exposure during pregnancy; however, the impact on maternal and infant health is not well understood. The aim of this study was to determine whether tea intake in the first trimester was associated with elevated concentrations of various pesticides in maternal blood or urine. Further, we examined the relationship between tea consumption and adverse birth outcomes. Data from the Maternal-Infant Research on Environmental Chemicals (MIREC) Study, a pan-Canada pregnancy cohort, were used. All singleton, live births (n=1898) with available biomarkers were included in the analyses. Descriptive statistics were used to characterize the population. The geometric means (GM) of organochlorine (OC) pesticide constituents or metabolites in maternal plasma (lipid adjusted) and organophosphate (OP) pesticide metabolites (adjusted for specific gravity) in maternal urine were calculated for participants who drank regular, green or herbal tea in the first trimester and for those who did not. Differences between groups were examined using chi-square or t-tests. Associations between frequency of drinking tea and adverse birth outcomes were examined using logistic regression (preterm birth and small-for-gestational-age) or generalized linear models (birthweight decile and head circumference). The GM of the OC pesticide constituent trans-nonachlor was 2.74mg/g lipid, and for metabolites oxychlordane and p,p'-DDE this was 1.94ng/g lipid and 55.8ng/g lipid, respectively. OP pesticide metabolite concentrations adjusted for specific gravity, were dimethylphosphate (GM: 3.19µg/L), dimethylthiophosphate (GM: 3.29µg/L), dimethyldithiophosphate (GM: 0.48µg/L), diethlphosphate (GM: 2.46), and diethylthiophosphate (GM: 0.67µg/L). There was no significant difference in mean concentrations for these OC or OP pesticide constituents or metabolites between tea drinkers - of any type - and non-tea drinkers. Further, no association was found between tea intake and adverse birth outcomes. Pesticide concentrations did not differ by tea intake. Further, tea intake in the first trimester was not associated with adverse birth outcomes. In this study population, there was no evidence for concern about tea intake being a source of the OP or OC pesticide metabolites measured or adversely affecting birth outcomes; however, tea intake was lower than national Canadian data for women of reproductive age. Copyright © 2015 Elsevier Inc. All rights reserved.
    Full-text · Article · Jun 2015
    • "As tea is subjected to infusion prior to consumption, residues of pesticides in tea and its transfer in brew must be monitored prior to permitting the consumption by human beings. A few reports are available on the degradation of certain commonly used pesticides and their residues in tea (Rajukkannu et al., 1981; Singh & Agnihotri, 1984; Manikandan et al., 2001 Manikandan et al., , 2005 Manikandan et al., & 2006 Kumar et al., 2004; Sood et al., 2004; Tewary et al., 2005; Seenivasan and Muraleedharan, 2009). However, there is n o published information on the residues of bifenthrin in black tea, under the climatic conditions of south India. "
    [Show abstract] [Hide abstract] ABSTRACT: Field experiments were conducted at two places in Tamil Nadu (India) to determine the residues of bifenthrin in black tea. Residues were quantified at different harvest intervals of '0' (3 hr), 1 st , 3 rd , 5 th , 7 th , 10 th and 14 th day after acaricide application. Persistence, dissipation pattern, half-life value and safe harvest interval of the acaricide in tea were calculated. Residues of bifenthrin dissipated exponentially after application at both the locations and reached below the European Union maximum residue limit (MRL) of 5 mg kg-1 on the 10 th day. Bifenthrin showed that like other acaricides it followed the first order dissipation kinetics. Half-life values varied from 2.4 to 3.2 days for bifenthrin and a safe harvest interval of 10 days is suggested for tea at the recommended dosage.
    Full-text · Article · Jan 2015
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