Milk-and-Dairy-Products-in-Human-Nutrition-FAO

Chapter 6 – Safety and quality 253
of new studies to better understand the risk to human health posed by BPA
(FAO and WHO, 2011b).
• 3-MCPD is a contaminant which occurs through food processing and has
been detected in a number of foods including infant formula and follow-up
formula. Studies to date show that there is a need for action to reduce the
levels but there is no acute risk (BfR, 2007). To investigate any potential risks
based on current data, 3-MCPD is on the priority list proposed for evaluation
by JECFA to undertake a toxicological and exposure assessment.
Environmental contaminants: toxic elements and compounds
Milk and dairy products can be a source of heavy metals, e.g. lead, cadmium and
nickel. These can originate in the environment, animal feeds, water used in dairy
farms and dairy plants and sewage sludge used as a soil amendment. It is well
established that lead and cadmium are toxic to humans, and children may have an
increased exposure to these metals compared with adults because of their lower
body weight (Khaniki, 2007).
Foods high in animal fat, such as milk, meat, fish and eggs, are the main source
of dioxins and PCBs in the human diet. These chemical enter the food chain from
the environment, industrial sources and feeds. These persistent organic pollutants
tend to accumulate in lipid tissues; hence, in lactating animals dioxins and dioxinlike
PCBs are excreted partly with milk fat. Key ways to reduce PCB and dioxin in
dairy products is to ensure feed is produced in areas that are not contaminated with
these chemicals and to avoid contaminated feeds (FAO and WHO, 2006b). Shortterm
exposure of humans to high levels of dioxins may result in skin lesions, such
as chloracne, patchy darkening of the skin and altered liver function. Long-term
exposure is linked to impairment of the immune system, the developing nervous
system, the endocrine system and reproductive functions. Dioxin is classified as
“known human carcinogen” (IARC, 1993). However, dioxin does not affect genetic
material and there is a level of exposure below which cancer risk would be negligible
(WHO, 2010).
Radionuclides are a rare contaminant in milk, but are of concern when radioactive
contamination results from a nuclear or radiological emergency. Experience
from the Chernobyl accident and more recently the release from the Fukushima
Daiichi plant have shown that immediately following an accident milk is susceptible
to contamination with high levels of iodine-131. However, likely health impacts
can be minimized immediately by administering potassium iodide tablets to the
affected population.
Intentionally added contaminants
The intentional contamination of food refers to the deliberate action of adding a
harmful or deleterious substance to food primarily for the purposes of economic
gain. It deceives the consumer and direct health consequences may also result.
The adulteration of milk with water, starch, gelatine, carbonates/bi-carbonates,
urea etc. for economic gain is reported to be a prevalent practice in India (Bhandare
and Waskar, 2010). Some of these adulterants can harm human health. For example,
adding water to milk can have adverse health effects or consequent risks in many
developing countries (Grace, Baker and Randolph, 2009).