Number 19 November 1993
MAFF UK - DIOXINS IN COWS' MILK
Index to MAFF UK Food Surveillance Information
Sheets, 1993
See also:
43: MAFF UK -
Dioxins in Cows' Milk (October 1994)
44: MAFF UK - Contaminants in Cow's Milk from
the Clitheroe Area (October 1994)
75:
MAFF UK - Dioxins in Cows Milk from the Bolsover Area (November 1995)
100: MAFF UK - Dioxins in Cows' Milk from
Farms Close to Industrial Sites (January 1997)
107: MAFF, UK - Dioxins and PCBs in
Cows Milk from Farms Close to Industrial Sites (June 1997)
120: MAFF UK - Dioxins in Cows' Milk from
Northern Ireland (August 1997)
123:
MAFF, UK - Dioxins and PCBs in Cows Milk from Farms Close to Industrial Sites:
1996 Survey Results (August 1997)
124: MAFF UK - Dioxins in Cows Milk from
the Bolsover Area (August 1997)
133:
MAFF, UK- Dioxins and PCBs in Cows' Milk from farms close to Industrial Sites:
Rotherham 1997 (November 1997)
134:
MAFF, UK- Dioxins and PCBs in Cows' Milk from the Bolsover Area - October 1997
(November 1997)
135: MAFF, UK-
Dioxins and PCBs in Cows' Milk from farms close to Industrial Sites:
Huddersfield 1997 (November 1997)
136: MAFF, UK- Dioxins and PCBs in Retail
Cows' Milk in England (December 1997)
143: MAFF UK - Dioxins and PCBs in Cows'
Milk from the Bolsover Area Collected in October and November 1997 (March 1998)
145: MAFF UK - Dioxins and PCBs in Farmed
Trout in England and Wales (March 1998)
184: MAFF UK - Dioxins and PCBs in UK and
Imported Marine Fish (August 1999)
Background
'Dioxins' is the generic term given to polychlorinated dibenzo-p-dioxins
and dibenzofurans. Concern over dioxins arose initially because one particular
dioxin, 2,3,7,8-TCDD, was found to produce clinical effects (chloracne) in
workers exposed to it through industrial accidents. It was also toxic to some
species of laboratory animals. The other dioxins are less toxic and
concentrations of those compounds are multiplied by a weighting factor
reflecting their relative toxicities to give a total dioxins content in terms of
'Toxic Equivalents' (TEQs). Dioxins are produced during various combustion
processes and are also unwanted by-products in the manufacture of certain
chlorinated compounds. As a result, dioxins are ubiquitous environmental
contaminants and are generally present in very low concentrations in all foods
including cows' milk. Past surveillance has shown that the normal expected
range of dioxins concentrations in cows' milk from farms close to
urban/industrial areas is 0.12 - 0.27 ng TEQ/kg (1 ng/kg is one part per
trillion).
Previous surveillance results for dioxins were summarised in the January
1993 issue of the Food Safety Directorate Information Bulletin. These results
showed elevated concentrations of dioxins in cows' milk from three farms (Farms
A, B and C) in the Bolsover area of Derbyshire, although concentrations had
fallen steadily during the period October 1990 to October 1992. Further samples
of milk were taken from five farms in the area, including Farms A and B, in
September 1993. Samples were not taken from Farm C owing to practical
difficulties in obtaining samples from the cows on that farm.
Results
Samples from farms F, G and H were taken from the bulk milk tanks on these
farms. Samples from Farms A and B were taken from individual cows as these
farms run suckler herds and do not currently produce milk for human consumption.
All samples were analysed by gas chromatography-mass spectrometry at the MAFF
Food Science Laboratory, Norwich, UK.
The concentrations of dioxins found (see table 1)
for all samples except those from Farm B were within the expected range for
farms close to urban/industrial areas. In all cases, the concentrations of
dioxins found were lower than in similar samples taken in August and October
1992, indicating that the degree of contamination in the area is continuing to
decrease.
Interpretation
With the exception of Farm B, the concentrations of dioxins found in the
milk are well below the Maximum Tolerable Concentration of 0.7 ng TEQ/kg set by
MAFF and the Department of Health. Farm B does not produce milk for human
consumption and there is therefore no direct risk to human health from the milk.
Contact point
For further information, please contact:
Dr Nigel Harrison
MAFF,
Food Safety and Science Group
Food Contaminants Division
Room 234 Ergon
House, c/o Nobel House
17 Smith Square
London SW1P 3JR
Tel:
+44 (0)171 238 6235
Fax: +44 (0)171 238 5331
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