Pesticide Residues in Milk and Milk Products - Pesticides: Evaluation of Environmental Pollution - page 578

18.4 Current Levels of Pesticide Residues in Milk
and Milk Products in Different Regions
Milk and milk products are mostly contaminated with organochlorine and organophos-
phorus pesticide residues, as reported in a number of studies carried out in various parts
of the world. Among OCP residues, DDT, HCH, heptachlor, chlordane, aldrin, and diel-
drin are detected in most of the cases. Around 355 samples of cow's milk and 448 samples
of national butter brands in Mexico were analyzed for OCP residues. HCH was found in
concentrations of 0.094 mg/kg in cow's milk and 0.093 mg/kg in butter, whereas DDT was
found in concentrations of 0.159 mg/kg and 0.049 mg/kg in milk and butter, respectively
(Waliszewski et al. 1997). In another study from the tropical part of Mexico, the milk sam-
ple was found to be contaminated with β-HCH at a concentration of 0.106 mg/kg followed
by pp′-DDT at a concentration of 0.078 mg/kg on fat basis and pp′-DDE at a concentration
of 0.051 mg/kg on fat basis. Some of the high-distribution brands of liquid milk in Mexico
were also contaminated with detectable levels of organophosphorus pesticide residues
including dichlorvos, phorate, chlorpyrifos, and chlorfenvinphos (Salas et al. 2003). Trace
levels of DDT and HCH were found in milk and milk product samples from Maharashtra
in India (Pandit et al. 2002). Commercially available butter samples from Punjab region
showed detectable levels of HCH (0.092-0.645 mg/kg) and total DDT residues (0.469 mg/
kg). The HCH residue includes α-, β-, γ-, and δ-HCH, and the DDT residue includes pp′-
DDD, pp′-DDE, and pp′-DDT (Gill et al. 2009). Buffalo's and cow's milk samples from dif-
ferent animal farms in Egypt, during the years 2008 and 2009, were also contaminated
with OCP residues: HCB, aldrin, heptachlor, heptachlor epoxide, chlordane, and DDT and
its derivatives. The concentration of HCB residue in buffalo's milk was 0.162 mg/kg fat
and that in cow's milk was 0.150 mg/kg fat. The concentrations of aldrin were 0.066 mg/
kg fat and 0.05 mg/kg fat in cow's and buffalo's milk, respectively (Abou Donia et al. 2010).
In Argentina, buffalo's milk samples were contaminated with heptachlor and heptachlor
epoxides, γ-HCH, and γ-chlordane (Lenardon et al. 2004).
18.5 Effects of Processing Treatments on Pesticide
Residues in Milk and Milk Products
Raw milk undergoes various processing treatments before consumption and is consumed
in different forms of milk products. So, it is important to know the effect of processing
treatments on residues and the distribution of pesticide residues in different milk products.
Raw milk undergoes a number of processing treatments like pasteurization, steriliza-
tion, concentration, separation of fat, fermentation, coagulation, and drying. Depending
on the type and nature of the pesticide compound, they are transferred from one phase to
another or degraded totally or partially to other compounds that may be more or less toxic
than the parent compound. Pasteurization has little effect on pesticide residues.
Pasteurization of raw milk at 93°C-100°C for a few seconds shows a small effect on β-BHC
and pp′-DDT. Sterilization at 121°C for 15 min showed 83.25%, 91.67%, and 68.7% loss of
β-BHC, lindane, and p,p′-DDT, respectively. However, p,p′-DDD was found in significantly
higher concentrations in UHT milk (Heck et al. 2007). The amounts of endosulfan sul-
fate and chlordane decreased by 17.1% and 11.2% on fat basis, respectively, in condensed