3.2 Quality and Safety Issues
3.2.1 Chemical Contaminants
Milk is a perishable food commodity having rich source of readily available nutrient
including lactose, fat, proteins, mineral, vitamins, etc. If milk is not handled properly, it may lose its natural quality during production, processing, and distribution
(Awasthi et al. 2012). The major contaminants that come across in milk and milk
products during milk production, dairy processing, or packaging are veterinary
drugs/drug residues, heavy metals, radionuclides, mycotoxins, pesticides, etc.,
which may enter through water, animal feed, and other environmental sources.
Antibiotic Residues
The most combative residues that arise in milk are antibiotic residues that may have
both technological and public health importance. Many of the antibiotic residues
were used in the treatment of dairy cattle which involves intra-mammary infusion as
well as the parenteral route of administering drugs to control mastitis, metritis, etc. In
addition, some drugs are administered to control endo- and ectoparasites and several
illnesses and to boost milk production (Korsrud et al. 1998). In animal husbandry,
antibiotics are extensively used for therapeutics, prophylaxis, and metaphylaxis and
as a growth promoter (Woolhouse et al. 2015; Rushton et al. 2014). Antibiotics
which are commonly used as feed additives include tetracycline, nitrofurans, and
sulfonamides (DeVries 1997). Many biologically active metabolites of antimicrobial
in milk and dairy products could result in anaphylaxis and allergic shock in sensitized individuals (Gustafson 1991). The most commonly used antimicrobials in dairy
cattle include β-lactams, tetracyclines, amino glycosides, macrolides, and sulfonamides (Mitchell et al. 1998). These drugs are also administered to animals through
different routes such as parenteral (intravenous, intramuscular, subcutaneous, intramammary, intrauterine, etc.), oral (in the food/water), topical (on the skin), inhalation, and rectal. Theoretically, in lactating cow administration of drugs through all of
the above routes may lead to an appearance of residues in milk and dairy products
(Mitchell et al. 1998). These measurable levels of the antibiotic are usually detectable in the milk for a few days after the last administration of the drug (EU/Codex
Alimentarius commission). Regulations have recommended the maximum residues
limits (MRLs) for some/many drugs in milk (European Commission 1997). Primary
concerns associated with antimicrobial residues in milk and dairy products are
expressed by the dairy processors who found that contaminated milk inhibits the
starter cultures used in the production of cheeses, yogurt, and other fermented dairy
products as well as it influences the results of the dye reduction tests used for milk
quality at the time of reception of raw milk (Jensen 1995). The main apprehension of
veterinary drug residues is the possible transmission of antibiotic resistance genecontaining bacteria from milk and dairy products to human population (Hao et al.
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H. V. Raghu et al.
3.2.1 Chemical Contaminants
Milk is a perishable food commodity having rich source of readily available nutrient
including lactose, fat, proteins, mineral, vitamins, etc. If milk is not handled properly, it may lose its natural quality during production, processing, and distribution
(Awasthi et al. 2012). The major contaminants that come across in milk and milk
products during milk production, dairy processing, or packaging are veterinary
drugs/drug residues, heavy metals, radionuclides, mycotoxins, pesticides, etc.,
which may enter through water, animal feed, and other environmental sources.
Antibiotic Residues
The most combative residues that arise in milk are antibiotic residues that may have
both technological and public health importance. Many of the antibiotic residues
were used in the treatment of dairy cattle which involves intra-mammary infusion as
well as the parenteral route of administering drugs to control mastitis, metritis, etc. In
addition, some drugs are administered to control endo- and ectoparasites and several
illnesses and to boost milk production (Korsrud et al. 1998). In animal husbandry,
antibiotics are extensively used for therapeutics, prophylaxis, and metaphylaxis and
as a growth promoter (Woolhouse et al. 2015; Rushton et al. 2014). Antibiotics
which are commonly used as feed additives include tetracycline, nitrofurans, and
sulfonamides (DeVries 1997). Many biologically active metabolites of antimicrobial
in milk and dairy products could result in anaphylaxis and allergic shock in sensitized individuals (Gustafson 1991). The most commonly used antimicrobials in dairy
cattle include β-lactams, tetracyclines, amino glycosides, macrolides, and sulfonamides (Mitchell et al. 1998). These drugs are also administered to animals through
different routes such as parenteral (intravenous, intramuscular, subcutaneous, intramammary, intrauterine, etc.), oral (in the food/water), topical (on the skin), inhalation, and rectal. Theoretically, in lactating cow administration of drugs through all of
the above routes may lead to an appearance of residues in milk and dairy products
(Mitchell et al. 1998). These measurable levels of the antibiotic are usually detectable in the milk for a few days after the last administration of the drug (EU/Codex
Alimentarius commission). Regulations have recommended the maximum residues
limits (MRLs) for some/many drugs in milk (European Commission 1997). Primary
concerns associated with antimicrobial residues in milk and dairy products are
expressed by the dairy processors who found that contaminated milk inhibits the
starter cultures used in the production of cheeses, yogurt, and other fermented dairy
products as well as it influences the results of the dye reduction tests used for milk
quality at the time of reception of raw milk (Jensen 1995). The main apprehension of
veterinary drug residues is the possible transmission of antibiotic resistance genecontaining bacteria from milk and dairy products to human population (Hao et al.
96
H. V. Raghu et al.