Abstract
Chocolate, a beloved indulgence worldwide, faces scrutiny due to potential heavy metal contamination. This study investigates the levels of lead (Pb), cadmium (Cd), and arsenic (As) in chocolates sold in Ung. Rimi, Nigeria.
Thirty chocolate samples were randomly collected from local retailers in Ung. Rimi. Heavy metal analysis was conducted using atomic absorption spectrometry (AAS). Results were compared against regulatory limits set by the National Agency for Food and Drug Administration and Control (NAFDAC) and the World Health Organization (WHO).
The findings revealed that the mean concentrations of Pb, Cd, and As in the chocolate samples were 0.03 mg/kg, 0.005 mg/kg, and 0.008 mg/kg, respectively. These levels were well below the permissible limits of 0.1 mg/kg for Pb, 0.005 mg/kg for Cd, and 0.01 mg/kg for As established by regulatory authorities.
While the detected heavy metal concentrations were within safe limits, ongoing monitoring and quality control measures are vital to ensure chocolate safety in Ung. Rimi. Future research should explore potential sources of heavy metal contamination in chocolate production and strategies to further safeguard consumer health.
TABLE OF CONTENTS
CONTENT
Cover page
Declaration
Certification
Dedication
Acknowledgment
Table of content
Abstract
CHAPTER ONE
1.0 Introduction
1.1 Background
CHAPTER TWO
2.0 Basics of Materials Characterization
2.1 Overview of Materials Characterization
2.1.1 Importance of Materials Characterization
2.1.2 Benefits and Applications
2.2 Properties of Materials
2.2.1 Physical Properties
2.2.2 Mechanical Properties
2.2.3 Chemical Properties
2.2.4 Electrical and Magnetic
2.3 Materials Characterization Method
CHAPTER THREE
3.0 Materials and method
3.1.0 Materials
3.2 methodology
3.2.0 Sample collection
3.2.1 Standard sample preparation
3.3 Analysis of metals ions using AAS
CHAPTER FOUR
4.0 Result
4.1 Discussion
CHAPTER FIVE
5.0 Conclusion
5.1 Recommendation
REFERENCE
CHAPTER ONE
1.0 INTRODUCTION
1.1 BACKGROUND
Food is one of the main sources of heavy metal in take in
consumers some heavy metals are essential nutrients (Cu, Ni, Zn) need by our
bodies but all of them can be harmful if ingest in heavily metal-contaminated
foods or beverage (Gideon et al,
2015).Recent trends in food safety issues have generated concern over the
presence and level of heavy metals in chocolate and chewing gums. For instance
the American environmental safety institute took legal action in 2002 against
chocolate manufacture for excessive level of Pb and Cd found in chocolate
(Anderson, 2011).Consequently, international legislative bodies, as well as
chocolate manufacture countries have introduce new regulations for the
protection of the health of their consumers (Ducos and Godula, 2010; Dickso,
2011) European Food Safety Authority (EFSA, 2011)
However, toxicological and environmental studies have interest
in the determinations of toxic elements in food. "Food safety"
implies absence or acceptable and safe levels of contaminants, adulterants,
naturally occurring toxins or any other substance that may make food injurious
to health on an acute or chronic basis. Food quality can be considered as a
complex characteristic of food that determines its value or acceptability to
consumers. Besides safety, quality attributes includes nutritional value,
organoleptic properties such as appearance, color, texture, taste and
functional properties (World Health Organization (WHO), 1998).
Taking into consideration that products passed
through different industrial processes and are packaged to provide a means of
protecting, marketing or handling, and most of them are printed colour inks on
the outer cover (Kim et al., 2008).
Importantly, food products such as candies that are likely to be consumed
frequently by small children are wrapped in colourful packages in order to
induce them to purchase the products. Heavy metals, such as Pb, Cr, Ti, Zn and
Cu can migrate from the printed surface to the food contact surface through
four mechanisms: blocking, rubbing, peeling and diffusion (Bradley et al.,
2005). Contamination of imported food products with heavy metals may cause a
serious risk for human health because of the consumption of even small amount
of metals can lead to considerable concentrations in human body there leading
to biotoxic effects. The biotoxic effects of heavy metals refer to the harmful
effects of heavy metals to the body when consumed above the bio-recommended
limits. Although individual metals exhibit specific signs of their toxicity,
the following have been reported as general signs associated with cadmium,
lead, arsenic, mercury, zinc, copper and aluminium poisoning: gastrointestinal
(GI) disorders, diarrhoea, stomatitis, tremor, hemoglobinuria causing a
rust–red colour to stool, ataxia, paralysis, vomiting and convulsion,
depression, and pneumonia when volatile vapours and fumes are inhaled
(McCluggage, 1991). The nature of effects could be toxic (acute, chronic or
sub-chronic), neurotoxic, carcinogenic, mutagenic or teratogenic. However, from
previous studies, majority of them are carried out in developed countries and
no literature of such studies in developing country like Nigeria where such
“Junks” are constantly circulated in our markets are end-up consumed by
families. Hence this study is necessitated to identify and characterized
imported candies. This is because, the safety of our food products supply is a
shared responsibility, from the fork of the food producing industry, regulatory
authorities, scientist and consumers. As part of this responsibility, this
study was conceived to assess the level of some heavy metals in candies sold in
Nigeria market and the potential risks caused as a result of its consumption.
In spite of the hazard effects of heavy metals on
public health, some of them are essential for normal physiological functions
such as copper and zinc. Also, copper sulphate exhibits clear reduction of
cadmium residues in animal tissues, the dietary deficiencies of copper, zinc,
calcium, iron, protein and an excess dietary fat cause an increase in the
absorption and toxicity of lead. Although there are standards set by the
quality control bodies such as National Agency for Food and Drug Administration
and Control (NAFDAC) and Standards Organization of Nigeria (SON) for
permissible concentrations of these contaminants in imported products.
1.2 Chocolate and Candies
Chocolate is one of the most popular confectioneries
consumed by all age groups. Among them children are the most attracted group of
consumer of chocolate and at the same time the most vulnerable for toxic
metals. Toxic metals accumulate in the body; even consumption of small amount
of metals can lead to neurotoxic, carcinogenic and brain disorder (Dias and
Wickramasinghe, 2013). Chocolate is a sweet confectionary of Theobroma Cacao
Seeds. The flavor of chocolate differs depending on the ingredient used and the
preparation method of chocolate. Since chocolate are more popular among
children, manufacture are very concern about their competitors in the market.
Due to this reason chocolate and other confectionaries are sold in a very
attractive manner, wrapped in colorful packaging materials.
1.3 Heavy Metals in Chocolates and Candies
Actually, this was not really news, since it has
long been known that cocoa (and many other foods) often contain trace amounts
of heavy metals. Cadmium is naturally found in soil a result, for example, of
volcanic activity, forest fires, and weathering of rocks and is taken up by
many plants, including cocoa plants. Soil can also be contaminated by
“man-made” sources of cadmium, such as from the manufacturing of certain
batteries and the use of phosphate fertilizers. How much of the heavy metal
ends up in cocoa beans depends on the geographic region, soil acidity, plant
variety, and other factors.
Further contamination may occur, to varying degrees,
during processing and manufacturing of cocoa products as well as during
transport and storage. Cadmium accumulates in the body and can have detrimental
effects on the kidneys, lungs, bones, and possibly fetal development; it’s also
classified as a probable human carcinogen. Unlike the Canadian government and
the European Union, the FDA has not set cadmium limits in foods or supplements.
The World Health Organization (WHO) suggests a maximum of 0.3 micrograms per
gram in dried plants. And California requires a warning label on products that
have more than 4.1 micrograms of cadmium per daily serving of a single product.
Cadmium limits have been determined in many different ways, but it’s unclear
which approach is best. (Berkeley Wellness, 2015).
Children with higher cadmium levels are three times
more likely to have learning disabilities and participate in special education,
according to a study led by Harvard University researchers. Dr. Robert Wright,
the study’s senior author, emphasized that the links to learning disabilities
and special education were found at commonplace levels previously thought to be
benign. Some studies of adult workers
have shown that high exposures can trigger neurological problems, and small,
earlier studies of children found links to mental retardation and decreased
IQs. (Environmental factor by NIH, 2012)
1.4 Heavy Metals Toxicity:
Toxicity of any metals is governed by several
factors; there are interaction with essential metals, formation of metals
protein, and complexes chemical form of the metals element, immune status, age
and stage of development of the host. Contamination of food products with heavy
metals may cause a serious risk for human health because of the consumption of
even a small amount of metals can lead to considerable concentration in human
body leading to biotoxic effects. The biotoxic effects of heavy metals refers
to the harmful effect of heavy metals to the body when consumed above the
bio-recommended limit. The nature of effect could be acute, chronic or
sub-chronic, neutrotoxic, concinogenic, mutagenic or tetratogenic (Ochuet al, 2012).
1.4.1 Lead and Chromium Toxicity:
Lead absorbed from the food and the atmosphere is
retained in tissue like lungs, liver, kidney, and bones. The short term and
long term exposure to high level of lead can course brain damage, paralysis,
abdominal pain, anemia, renal diseases, memory loss, damage to kidney,
reproductive and immune system (Toxicology fact sheet series Food Safety
Authority of Ireland, 2009).
Chromium can exist as Cr (III) or Cr (VI). Cr (IV)
form is highly toxic. Cr (IV) exposure has been known to be associated with
cancer induction in humans, especially bronchial carcinoma and lung cancer
(Kim, Ogunfowokmet al, 2005 ;).
1.4.2 Nickel Toxicity:
Nickel is also a well known carcinogen to human, by
altering the DNA functions. Even through their DNA-damaging potentials are
rather weak, they interfere with the nucleotide and base excision repair at
low, nontoxic concentrations. For example both water-soluble Ni (ii) and
particular black NiO greatly reduced the repair of DNA. Ni (ii) disturbed the
very first step a nucleotide excision repair (Hartmann and Hartwig, 1998).
Many different studies and techniques for heavy
metals determination in different food stuffs have been reported in the
literature. Concentration of selected metals in candies and chocolate consumed
in southern Nigeria ware analysed, the result in chocolate level of Ca, Cd, Ni,
Cr, Cu, Pb, Mn, Zn, Fe, Co, and Mg, in candies and chocolate with mean
concentration of metals in both confectionaries which ranged between 7.7-1405
µg/g. (Chukwujundu 2013; Milouret al,
2011).
1.5 Aim and Objectives
The aim of this study was to identify the heavy
metals (Ni, Cd, and Pb) that might be present in low concentrations or not at
all in some Chocolate, as well as to provide data that could be used to develop
preventive measures.
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