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Theses

Toxic risk assessment of specific chemical substances and contaminants (Food additifs and Mycotoxins)

Lama Soubra
Abstract : Following an increasing number of crisis, food hazards entered in the category of major concerns for humans and thereafter governments and international bodies improved the food safety systems in order to reduce or prevent food borne illness. In Lebanon the food industry and intensive agriculture recognized a rapid development that systems ensuring food safety are deficient or absent, and that climate and storage conditions in addition to local food habits are favorable to the presence of certain types of hazards that present health risks. The objective of this research is to assess the level of food safety in relation with certain microbial contaminants and chemicals (food additives (benzoates, sulphites, BHA and BHT) and mycotoxins (ochratoxin A, aflatoxinsBG and deoxynivalenol)) in a selection of foods that are available in the Lebanese market on one hand, and on the other hand to assess the risks related to the selected food additives and mycotoxins for two subgroups of the Lebanese population considered to be at risk: children and teenagers, in order to establish a hierarchy of the importance of the risk that these substances represent to the health of these subgroups. Available foodstuffs in the Lebanese market that are susceptible to contain these hazards were identified and analyzed. 596 food samples were analyzed microbiologically. These belonged to 6 food categories: soft drinks, fruit juices, dairy products, potato chips, biscuits and canned foods that are produced by the Lebanese food industry. 2200 food samples were analyzed chemically to determine either their content in food additives (421 samples), or the degree of their contamination by the mycotoxins (1779 samples). The representativness of the samples was ensured by the fact that those were withdrawn randomly, during two different seasons, from the major food markets in a way to cover the main brands available in the Lebanese market. The analyses were performed in the laboratories of Saint Joseph University and of the National Agricultural Research Institute (IRAL) according to validated methods and on foods as consumed. The risk assessment was carried out according to the steps of the scientific process of risk assessment i.e. hazard identification and characterization, exposure assessment and risk characterization. Dietary exposures to food additives and mycotoxins was obtained by combining the food consumption data obtained from an individual food survey specially developed and carried out during this research, with the contamination data obtained by chemical analysis. The risk was characterized by comparing the estimated dietary intakes with the toxicological reference values (TRV) established for these substances by the international bodies and also by calculating the percentage of individuals that have dietary intakes exceeding these TRV. The results of microbial analysis showed that only 9% of the analyzed food did not comply with current microbial food standards. The results of chemical analysis showed that the food additives are present in a wide range of foods including unauthorized foods according to the national standards in 70% of cases for benzoates, 15% of cases for sulphites, 13% of cases for the BHA and 3.5% of cases for the BHT, and at levels exceeding the authorized levels in 70% of cases for benzoates, 62% of cases for sulphites and 37% of cases for BHA. Moreover they showed that the studied mycotoxins are present at levels conform to the national, international and European standards. The results of the risk assessment showed that, among the studied hazards, only aflatoxins BG constituted a risk for the studied subgroups. In fact the mean, the p75 and the p95 of the distribution of exposure were below the Toxicological Reference Value (TRV) fixed for benzoates, sulphites, BHA, BHT, OTA and DON, and above the TRV fixed for aflatoxins with values ranging from 182-769% the TRV for children and 144- 650% of the TRV for the 8 teenagers group, and a percentage of individuals exceeding this TRV of 58% for children and of 52% for teenagers. Results also showed that it was necessary to bring special attention to the exposure of some group of the population such as children and high consumers for whom the risk of being exposed to a level higher than the toxicological reference values for food additives and mycotoxins exist. The main contributors to the exposures of benzoates, sulphites, BHA, BHT and the three mycotoxins were found to be, respectively, sodas and fruit juices, dried fruits, biscuits, chewing gum and cereal products.
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Submitted on : Monday, December 1, 2008 - 8:00:00 AM
Last modification on : Friday, October 23, 2020 - 4:52:40 PM
Long-term archiving on: : Friday, September 10, 2010 - 12:47:47 PM

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Lama Soubra. Toxic risk assessment of specific chemical substances and contaminants (Food additifs and Mycotoxins). Chemical Sciences. AgroParisTech, 2008. English. ⟨NNT : 2008AGPT0014⟩. ⟨pastel-00004382⟩

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