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Abstract
Antibiotics are used by the poultry industry and poultry veterinarians to enhance
growth and feed efficiency and reduce disease. Antibiotic usage has facilitated the
efficient production of poultry, allowing the consumer to purchase, at a reas onable
cost, high quality meat and eggs. Antibiotic usage has also enhanced the health and
well-being of poultry by reducing the incidence of disease. Although these uses
benefit all involved, unfortunately, consumer perceptions are that edible poultry
tissues are contaminated with harmful concentrations of drug residues (Donoghue,
2003).
Drugs used in food animals can affect the public health because of their secretion
in edible animal tissues in trace amounts usually called residues. For example,
oxytetracycline (Salehzadeh et al., 2006) and enrofloxacin residues (Salehzadeh et
al., 2007) have been found above the maximun residual level in chicken tissues.
Similarly, diclofenac residues were reported to be the cause of vulture population
decline in Pakistan (Oaks et al., 2004). Some drugs have the potential to produce
toxic reactions in consumers directly; for example, clenbutarol caused illness in 135
peoples as a result of eating contaminated beef in Spain in 1990. Other types of drugs
are able to produce allergic or hypersensitivity reactions. For example, 2-β-lactam
antibiotics can cause cutaneous eruptions, dermatitis, gastro-intestinal symptoms and
anaphylaxis at very low doses. Such drugs include the penicillin and cephalosporin
groups of antibiotics (Paige et al., 1997). Indirect and long term hazards include
microbiological effects, carcinogenicity, reproductive effects and teratogenicity.
Microbiological effects are one of the major health hazards in human beings.
Antibiotic residues consumed along with edible tissues like milk, meat and eggs can
produce resistance in bacterial populations in the consumers. This is one of the major
reasons of therapeutic failures amongst such peoples. Certain drugs like 3 -nitrofurans
and nitroimidiazoles can cause cancer in human population. Similarly, some drugs
can produce reproductive and teratogenic effects at very low doses consumed for a
prolonged period of time. One such example is vaginal clear cell adenocarcinoma and
benign structural abnormalities of uterus with diethyl stilbesterol (Sundlof, 1994).
Antibiotics are important in animal husbandry because they significantly enhance
growth when added to animal feed, although European Union (EU) legislation has
forbidden this practice since 2006 (European Commission, 2003). Several antibiotic
families are used in veterinary medicine: B-lactams; Tetracyclines;
Chloramphenicols; Macrolides; Spectinomycin; Lincosamide; Sulphonamides;
Nitrofuranes; Nitroimidazoles; Trimethoprim; Polymyxins; Quinolones and
Macrocyclics. Macrocyclics are characterized by their high selectivity as they are
Introduction 2
chiral selectors (Ward and Farris, 2001). The extensive use of antibiotics has
triggered the development of bacterial resistance (Novais et al., 2010), which, in
recent years, has become an international concern (Teuber, 2001). Much attention
has been paid to food-producing animals as potential source of antibiotic resistant
bacteria in humans. As a result, there is increasing pressure on laboratories
responsible for ensuring the safety of food for human consumption. Legislation
regarding the control of antibiotic residues in live animals and animal products is
given in Council Directive 96/23/EC (European Commission, 1996), and maximum
residue limits (MRLs) have been established for different matrices, so fast, sensitive
methodologies to determine antibiotic residues in food samples are critical in food
safety control laboratories. In this field, Kantiani et al., (2009) presented a review on
the analytical methods developed for penicillin and cephalosporin residues in milk
and feed samples (Kantiani et al., 2009).
Drugs used in food animals can affect the public health because of their secretion in edible animal tissues in trace amounts usually called residues. For example, oxytetracycline (Salehzadeh et al., 2006) and enrofloxacin residues (Salehzadeh et al., 2007) have been found above the maximun residual level in chicken tissues. Similarly, diclofenac residues were reported to be the cause of vulture population decline in Pakistan (Oaks et al., 2004). Some drugs have the potential to produce toxic reactions in consumers directly; for example, clenbutarol caused illness in 135 peoples as a result of eating contaminated beef in Spain in 1990. Other types of drugs are able to produce allergic or hypersensitivity reactions. For example, 2-β-lactam antibiotics can cause cutaneous eruptions, dermatitis, gastro-intestinal symptoms and anaphylaxis at very low doses. Such drugs include the penicillin and cephalosporin groups of antibiotics (Paige et al., 1997). Indirect and long term hazards include microbiological effects, carcinogenicity, reproductive effects and teratogenicity. Microbiological effects are one of the major health hazards in human beings. Antibiotic residues consumed along with edible tissues like milk, meat and eggs can produce resistance in bacterial populations in the consumers. This is one of the major reasons of therapeutic failures amongst such peoples. Certain drugs like 3-nitrofuransand nitroimidiazoles can cause cancer in human population. Similarly, some drugs can produce reproductive and teratogenic effects at very low doses consumed for a prolonged period of time. One such example is vaginal clear cell adenocarcinoma and benign structural abnormalities of uterus with diethyl stilbesterol (Sundlof, 1994