EXPOSURE AND RISK ASSESSMENT OF AFLATOXIN INGESTED CEREALS AND GRAINS BY UNIVERSITY STUDENTS

ABSTRACT
The objective of this study was to assess the exposure and health risks associated with the consumption of kenkey by students of KNUST. Students completed a food dietary questionnaire to gather their exposure frequency and amount of kenkey eaten. Kenkey samples were collected from various students’ food joints and homogenized. Sirhan method of extraction and purification was used to extract the aflatoxin from the kenkey. HPLC was used to determine the concentrations of each group of aflatoxin. The probabilistic approach was used to model the chronic exposures using the Monte Carlo simulation of the Palisade @Risk software. The mean concentration of aflatoxin was 4.78 ng/g. Probabilistic approach was used to estimate the chronic daily exposure. The chronic exposures ranged between 0.024-1.09 ng/g bw/day. The chronic exposure and reference dose of aflatoxin were used to estimate the hazard quotient. The hazard quotient was below the tolerable limit (1). The chronic exposure for both carcinogen and non-carcinogen groups of aflatoxins were also estimated of exposure. There was a significant health concern as the margin of exposure (792.06) for the carcinogen group was below the threshold level (10,000). Aflatoxin contamination must be given a serious attention and effective measures must be in place to curb the contamination of aflatoxin.


CHAPTER ONE
1.0 INTRODUCTION
1.1 Background
Aflatoxins are mycotoxins primarily produced by Aspergillus nomius, Aspergillus flavus and Aspergillus parasiticus. They are known to be acutely toxic, mutagenic, carcinogenic, teratogenic and immunosuppressive (Wild and Gong, 2009) and classified as G1, G2, B1 and B2 based on their chemical structures. Aflatoxins are found in most staple foods in their raw forms such as maize (Murphy et al., 2006). Previous reports in several studies have reported the occurrence of aflatoxins in foods from the Ghanaian market (Khlangwiset et al., 2011). Out of the eighteen known aflatoxins (AF), just AFG1 AFG2, AFB1 and AFB2 are reported in agricultural food crops (Riba et al., 2010). Aflatoxin B1 is the only metabolite among the four known groups that is very carcinogenic (Assunção et al., 2018). The International Agency for Research on Cancer (IRAC) reported Aflatoxin B1 is a hepato carcinogen when hazard is chronically exposed and causes acute hepatitis and can end up causing cancer of the liver (IARC, 2002 and IARC, 2012). According to Assunção et al. (2018) aflatoxin B1 have been grouped as class 1 potential carcinogen to humans.

Kenkey, which is a cereal-based food, prepared from maize, is consumed by most Ghanaians and several studies have reported the occurrence of aflatoxin in kenkey (Shephard, 2003). According to Assunção et al. (2018), cereal-based foods is one of the commonest means to human exposure to aflatoxin and other mycotoxins. Previous studies have shown that approximately 25% of cereals produced globally are contaminated by mycotoxins (FAO/WHO, 2002). Aflatoxin in maize is mostly produced as a result of poor handling of maize in the supply chain including storage. If the moisture exceeds 12% and humidity is not right, stored maize is prone to be contaminated with aflatoxin.

To be able to estimate the exposure and risk of aflatoxin in kenkey, several methodologies such as dietary recall, and dietary history or food-frequency methods are used. Assuming that the consumption of kenkey is considered as chronic daily intake, dietary recall should be appropriate as it could be expedient to recollect the exact food intake measurements (Cano-Sancho et al., 2013). In order to make an accurate judgment on the risk that aflatoxin in kenkey poses, it is imperative to take into consideration all aspects risk indices. Risk characterization estimates the severity of an identified hazard and the probable adverse health effects of the hazard (Cano-Sancho et al., 2013). At the present time, the contamination cereal-based foods by aflatoxin needs a close attention, specifically because of the adverse health effects as a result of mycotoxins exposure could lead to diverse toxicity and carcinogenicity (Speijers et al., 2004). Previous studies only focused on the occurrence of aflatoxin and not much on exposure and risk assessment especially in Ghana (Assunção et al., 2015). The chemical compositions and knowledge of the toxicities of aflatoxin has been used to envisage the toxicity and risk it presents. For example, in order to quantify the risk associated with aflatoxin exposure, hazard quotient is used, and it is expressed as the ratio of the chronic human exposures to the reference dose of aflatoxin. On the other hand, margin of exposure (MOE), which is defined as the ratio of bench mark dose lower limit (BMDL10) to estimated exposure of a hazard. According to Syberg et al. (2008) these procedures of risk assessment are based on the theories of Independent Action (IA) and Concentration Addition (CA). According to Assunção et al. (2016), MOE is aimed at both carcinogenic and genotoxic risk assessment and is mostly used for the cumulative risk assessment. Lifetime risk is another way to estimate risk of a hazard. It is multiplication of the potency factor and chronic daily intake that are exposed to the population. The slope factor (also known as the potency factor) which is the risk produced by a lifetime average dose of 1 mg/kg-day is mostly originated from certified studies. Very few studies have been conducted on the exposure and risk assessment exist on cereal-based products such as kenkey Murphy et al., 2006). The European Food Safety Authority (EFSA) instituted a minimum limit of 5 µg/kg for total aflatoxin in cereals (van Egmond et al., 2007). The objective of this study was to estimate the exposure and risk associated with aflatoxin exposure through the consumption of kenkey.

1.2 Problem Statement and Justification
As a result of the high standard of living on university campuses in Ghana, many students resort to consuming cheaper food alternatives such as cereal-based (kenkey). However, there have been documented evidence of poor handing of cereals on the market especially if the grains are not sourced from certified maize grits producers (Shephard, 2003). Thus, it can be assumed that consumers of these cereal-based foods are at risk of adverse health effects that result from aflatoxin known to be present in the poorly handled grains as a result of the growth of Aspergillus flavus. Therefore, there is the need to quantify the exposure and determine if the concentrations of aflatoxins in kenkey consumed by many students on KNUST campus are enough to pose a significant health concern or risks such as cancers or any related toxicities. Since reports from the KNUST Hospital indicates increasing number of students who are treated of Hepatitis B.

1.3 Main Objective
To estimate the dietary exposure and health risks associated with the consumption of kenkey.

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Item Type: Ghanaian Postgraduate Material  |  Attribute: 35 pages  |  Chapters: 1-5
Format: MS Word  |  Price: GH50  |  Delivery: Within 30Mins.
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