الفهرس 
HistamineOnly 14 pages are availabe for public view
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Abstract
The food safety and its quality assurance for consumer become has a
major concern. Egypt should establish an integrated regulatory system for
food safety through which a national residues surveillance programme
should established to monitor the presence of different contaminants in food
such as pesticide residues, veterinary drugs including chloramphenicol,
sulfonamides, tetracyclines, macrolides, β- Lactam and qunolines , histamine
as well as highly toxic elements of heavy metals such as lead, cadmium,
copper, mercury and arsenic, to protect the human health from different
possible risks in addition to having the probability to export its food to
European countries.
Egypt as a third country should to submit monitoring plans to the
European Commission (EU) for approval every year to be included in the
exporting country list. Food of animal origin such as aquaculture fish, honey,
poultry are banned for exportation to EU due to lack of national system of
inspection of the residues and contaminates. Egypt has no chance to export
food to European Commission due to lack of such data needed; including the
testing laboratory as well as the national monitoring control plan. The testing
of such contaminants should be performed by the official and accredited
laboratories.
This study aimed to ensure the Egyptian food quality especially fish to
be safeguarded to human consumption and so protect them from high risk
hazardous and to facilitate the international trade through ensuring the safety
and quality of fish from residues of veterinary drugs, histamine and heavy
metals, thereby being legally exported to different countries according to international standards and regulations. This was done by developing and
optimizing different methods of analysis for veterinary drugs, histamine and
metallic contaminants to improve cost-effectiveness and explicabilities and to
meet the performance requirements necessary for use as regulatory methods
for international trade and consumer protection needs.
Veterinary drugs residues and biogenic amines especially histamine and
metallic contaminants which contribute large groups of food contaminants,
are becoming of great concern in food safety and international trade of food
products. Maximum residue limits (MRL’s) for some veterinary drugs and
histamine and maximum limits for some metallic contaminants have been
established by many organizations, such as the Codex Alimentarius ,
European Union (EU) and US Food and Drug Administration (FDA) for
different types of foods to eliminate the technical barriers and enhance the
international trade as well as ensuring that consumers are not exposed to
unsafe levels of hazardous materials.
Histamine is a biogenic amine generated post-mortem in fish and
certain fish-based products due to product mishandling, bad storage and
abuse which causes the allergy-like symptoms of scombroid poisoning,
estimation of histamine levels in foods is desirable because of its potentially
toxic effects and also because it can be used as indicator of food freshness
and spoilage during transportation.
In the current study rapid, precise, and reliable method for
quantification of histamine was developed and optimized to identify and
detect histamine in fish and fish products to asses the quality for food safety
before exporting to European countries and prevent consumer from health
hazards. Method development includes optimization of different analytical
method steps; histamine derivatization; extraction with different solvents,study of matrix effect and optimization of HPLC conditions. Different
method validation parameters were studied to ensure the fitness for purpose
of the analytical method, for example, limit of detection, limit of quantitation,
method recovery, linearity, method precision and estimation of measurement
uncertainty. The average recovery was 96% with coefficient of variation (CV
%) less than 8%. The uncertainty was estimated and was set to 26.4%. The
performance of the proposed method was checked with a sample from the
Food Analysis Performance Assessment Scheme (FAPAS) as an external
quality control; the z- score was found within acceptable range │Z│< 2.
Thirty four fish samples and 16 canned tuna samples were subjected to
histamine assessment using the validated method. Only one sample was
contaminated with histamine and exceeding the permissible limit set by
Codex Alimentarious and European Commission.
The study also included analysis of veterinary drug residues in
aquaculture fish. However, most of the aquaculture systems in the world are
based on intensive cultivation methods. These methods are characterized by
high stock density and volume, use of antibiotics, antifungal and other
pharmaceuticals can cause serious health problems in consumers.
In this study, simple and reliable multiresidue method of analysis for
determination of veterinary drugs residues in different animal products was
developed. In this method different drugs groups, e.g. sulfonamides,
tetracyclines, macrolides, β- Lactam , qunolines and unauthorized antibiotics
such as chloamphenicol were optimized and determined with good sensitivity
using LC/MS/MS and fulfill the Codex and EU regulations. Most of
compounds (19 drugs) were analyzed in electrospray ionization positive
mode (ESI+) while only chloamphenicol was analyzed in electrospray
ionization negative mode (ESI-). Method development includes optimization of different analytical method steps; extraction with different solvents, study
of matrix effect and optimization of LC-MSMS conditions. Different method
validation parameters were studied to ensure the fitness for purpose of the
analytical method, for example, method recovery, linearity, method precision
and estimation of decision limit (CCα) and the detection capability (CCβ). In
general, the average recovery ranges of the test compounds are acceptable
according to the European Commission guidelines 657/2002/EC. However,
the limit of quantitations (LOQ) was 25 ug/kg for all tested drugs except for
chloramphenicol it was 0.15 ug/kg. The method performance was tested
using proficiency test to evaluate the compliance with │Z│ score; where zscore ≤ ±2 indicated acceptance. The developed and validated method was
used to monitor the levels of veterinary drugs in fish samples collected from
Egyptian local market. Fifty samples of different types of fish samples (Nile
Tilapia, Nile Perch, Tilapia gallilly , Tilapia Zillii ) were analyzed using the
proposed method for presence of the 20 veterinary drugs under investigation.
No residues were found in the tested samples. Further investigations should
be done to cover more aquaculture farms as well as more fish types.
Heavy metals also addressed in this study as they are a group of
environmental contaminate pose hazards to human health. However, heavy
metals are discharged into the environment through urban discharge,
agriculture, mining, combustion and industrial discharge, and can accumulate
to toxic concentrations and cause ecological damage, and subsequently be
transferred to humans through the food chain. Mercury, lead, cadmium and
arsenic are considered to be the most dangerous metals and have been
associated with serious adverse health effects. Copper, although an essential
metal, may produce toxic effects such as liver cirrhosis, dermatitis and neurological disorders when consumed in excessive amounts in foods such as
fish and fish products.
Development of accurate and sensitive method for determination of
11 elements including, lead (Pb), Cadmium (Cd), Arsenic (As), Copper (Cu)
and mercury (Hg), zinc (Zn), Aluminum (Al), Iron (Fe), chromium (Cr),
Magnesium (Mn), Tin (Sn) using atomic absorption spectrophotometer
(AAS) with microwave digestion has been done. The obtained mean
recoveries range was 86-104% with CV% of 7-11%. The method
performance was also tested using proficiency test to evaluate the compliance
with │Z│ score; where z-score ≤ ±2 indicated acceptance for Cd , Hg and
Cu.
The applicability of the validated method to routine analysis was
doneby analysis of 131 fish samples collected from Egyptian local markets
during 2009/2010. The validated method was then applied for the detection
and determination of heavy metals. The results were reported and assessed
based on the maximum tolerance value set by Codex Committee of Food
Additives and Contaminants (CCFAC, 1993 amended 2009). Lead, cadmium
and mercury were the violated elements with percentages of 3%, 9.9% and
3%, respectively.