title: Residues and contaminants in tea and tea infusions: a review.
abstract: Consumers are very aware of contaminants that could pose potential health hazards. Most people drink tea as an infusion (adding hot water); however, in some countries, including India, China and Egypt, tea is drunk as a decoction (tea and water are boiled together). An infusion usually brings the soluble ingredients into solution, whereas a decoction brings all soluble and non-soluble constituents together. Therefore, a cup of tea may contain various kinds of contaminants. This review focuses on green and black tea because they are most commonly consumed. The target was to examine the transfer rate of contaminants - pesticides, environmental pollutants, mycotoxins, microorganisms, toxic heavy metals, radioactive isotopes (radionuclides) and plant growth regulators - from tea to infusion/brewing, factors contributing to the transfer potential and contaminants degradation, and residues in or on the spent leaves. It is concluded that most contaminants leaching into tea infusion are not detected or are detected at a level lower than the regulatory limits. However, the traditional practice of over-boiling tea leaves should be discouraged as there may be a chance for more transfer of contaminants from the tea to the brew.
authors.affiliation: a Biotechnology Research Institute, College of Agriculture and Life Sciences , Chonnam National University , Buk-gu , Gwangju 500-757 , Republic of Korea.
authors.forename: A M
authors.initials: AM
authors.lastname: Abd El-Aty
authors.forename: Jeong-Heui
authors.initials: JH
authors.lastname: Choi
authors.forename: Md Musfiqur
authors.initials: MM
authors.lastname: Rahman
authors.forename: Sung-Woo
authors.initials: SW
authors.lastname: Kim
authors.forename: Alev
authors.initials: A
authors.lastname: Tosun
authors.forename: Jae-Han
authors.initials: JH
authors.lastname: Shim
mesh_terms: D002681:China; D004534:Egypt; D004785:Environmental Pollutants / Q000032:analysis; D005506:Food Contamination / Q000032:analysis*; D000075322:Heavy Metal Poisoning; D006801:Humans; D007194:India; D019216:Metals, Heavy / Q000032:analysis; D009183:Mycotoxins / Q000032:analysis; D010573:Pesticide Residues / Q000032:analysis*; D010575:Pesticides / Q000032:analysis*; D018515:Plant Leaves / Q000737:chemistry; D011041:Poisoning; D011868:Radioisotopes / Q000032:analysis; D013662:Tea / Q000737:chemistry*
chemical_list: D004785:Environmental Pollutants; D019216:Metals, Heavy; D009183:Mycotoxins; D010573:Pesticide Residues; D010575:Pesticides; D011868:Radioisotopes; D013662:Tea
keywords: black tea; brewing; consumers; contaminants; green tea; infusion; residues