Analysis of organochlorine residues and bacteria contamination in tea samples

Yap, Boon Keat (2008) Analysis of organochlorine residues and bacteria contamination in tea samples. Universiti Malaysia Sabah. (Unpublished)

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Abstract

Tea (both black and green) is consumed throughout the world, both for pleasure and therapeutic purposes. Most people are unaware of their involuntary exposure to residues of pesticides lingering in tea and so possibly transferring into infusions of tea. Therefore, organochlorine residues which are highly persistent in environment and foods were determined in this study. For this purpose, a total of eight samples, represented by Sabah tea, Pu-Erh tea, and green tea were investigated. A liquid-liquid extraction, clean up and followed by gas chromatography-mass spectrometry technique was used to determine the presence and levels of these organochlorine residues. The results showed all persistent organochlorine pesticides were not detectable in all tea samples up to detection limit of 1mgL�¹. Therefore, an appropriate comparison with Food Act and Regulations by Laws of Malaysia cannot be made due to the permitted levels were lower than 1 mgL�¹. The microbial groups important in foods consist of several species and types of bacteria, yeasts, molds, and viruses which are able to cause foodborne diseases. Microbiological studies were performed according to EN-ISO Standards. Sabah tea and green tea samples were free from microbial contamination including Aspergillus niger ATCC 16404 and Salmonella typhimurium ATCC 14028. Pu-Erh tea samples showed a microbial contamination which exceeded the limit by Food Act and Regulations, but they were free from contamination of Aspergillus niger ATCC 16404 and Salmonella typhimurium ATCC 14028.

Item Type: Academic Exercise
Uncontrolled Keywords: Sabah tea, organochlorine residues, Pu-Erh tea, green tea, gas chromatography-mass, foodborne diseases
Subjects: Q Science > QD Chemistry
Divisions: SCHOOL > School of Science and Technology
Depositing User: MDM SITI AZIZAH IDRIS
Date Deposited: 06 Mar 2014 08:25
Last Modified: 12 Oct 2017 05:39
URI: http://eprints.ums.edu.my/id/eprint/8411

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