Number 48 January 1995
MAFF UK - SURVEILLANCE OF UK CEREALS FOR OCHRATOXIN A
Index to MAFF UK Food Surveillance Information
Sheets, 1995
see also:
28: MAFF UK - Surveillance of UK
Cereals for Ochratoxin A (May 1994)
73: MAFF UK - Surveillance for Ochratoxin
A in Retail Coffee Products (September 1995)
80: MAFF UK - Surveillance for
Ochratoxin A in Green (unroasted) Coffee Beans (March 1996)
95: MAFF UK - Ochratoxin A in
Cereals and Flour, and Carry-Over Into Retail Processed Foods (October
1996)
130: MAFF UK - Survey of
Aflatoxins and Ochratoxin A in Cereals and Retail Products (November
1997)
171: MAFF UK - Survey of
Ochratoxin A in Grain Traded by Central Depots 1997-1998 (February 1999)
172: MAFF UK - A Survey of Human
Exposure to Ochratoxin A (April 1999)
185: MAFF UK - 1998 Survey of
Retail Products for Ochratoxin A (August 1999)
192: MAFF UK - Survey for
Aflatoxins, Ochratoxin A, Fumonisins and Zearalenone in Raw Maize
Background
The presence of ochratoxin A (OA) in cereals infected by Aspergillus
and Penicillium species has been reported in many countries
including the UK. Aspergillus and Penicillium mould
species can produce OA in stored wheat over a wide range of temperatures
when moisture content is in excess of 15 percent. In 1985, ten samples of
UK wheat were taken, of which three were naturally contaminated with OA at
concentrations of 10 µg/kg, 30 µg/kg and 1900 µg/kg after
storage for 18 weeks at 20°C and 20 percent moisture content. In
1990, surveillance of OA in the UK found widespread but low level
contamination (1 µg/kg) of cereals and pork products, but a small
number of samples (3 out of 248) contained concentrations above 10 µg/kg.
Following the advice from the Committee on Toxicity of Chemicals in
Food, Consumer Products and the Environment (COT), that OA should be
considered a genotoxic carcinogen, the Food Advisory Committee (FAC)
recommended that industry should develop procedures to reduce levels in
cereals to the lowest technologically achievable.
To determine the background levels in UK cereals, a two phase survey was
set up in co-operation with the Home Grown Cereals Authority (HGCA). In
the first phase of the survey carried out in 1993, stored intervention
wheat and barley samples from 1992 were included in the surveillance
programme. Wheat is accepted for storage between November and May but
there is a possibility of OA production prior to acceptance from the time
of harvest onwards. Samples of wheat purchased by UK millers between
September and November 1993 were therefore included in the survey.
The second phase of the survey included barley samples collected on
harvest, stored barley from the 1993 harvest and stored wheat samples
(purchased from UK millers), from the 1994 harvest.
Results
The samples were analysed by the Flour, Milling and Baking Research
Association (FMBRA) by an HPLC method with fluorescence detection,
following clean-up by OA specific immunoaffinity columns. The limit of
detection of the method was 1 µg/kg. Results of the survey are
presented in Tables 1 and 2 (see below). A total of 1061 cereal samples
were analysed and OA was not detected in 96 percent of samples (1020).
In phase 1 of the survey (1993), 611 samples were analysed and OA was
not detected in 609 of them (99.7 percent). Only two wheat samples (from
the UK Millers) were found to contain OA both at 15 µg/kg.
In phase 2 of the survey (1994), a total of 450 samples were analysed
and OA was not detected in 411 samples (91.3 percent). Twenty-two stored
wheat samples (9 percent), collected in 1994 contained OA at
concentrations above 1 µg/kg and 7 samples contained OA above 5 µg/kg,
with the highest concentration being 32 µg/kg. Seven samples (5
percent) of barley collected at the 1994 harvest and 10 stored barley
samples(20 percent) from 1993 contained OA at concentrations above 1 µg/kg.
One barley sample from the 1994 harvest, contained OA above 5 µg/kg,
at a concentration of 33 µg/kg. For stored barley, two samples
contained OA above 5 µg/kg, at concentrations of 5.7 and 14 µg/kg.
Table 1: Results of 1993 survey of wheat and barley for ochratoxin
A (Phase 1) |
Sample type |
Number of samples analysed |
Number of samples containing OA inthe range (µg/kg)
|
<1 |
1-5 |
5-10 |
>10 |
|
Wheat at harvest |
384 |
384 |
- |
- |
- |
|
Wheat (1992 stored) |
25 |
25 |
- |
- |
- |
|
Barley (1992 stored) |
73 |
73 |
- |
- |
- |
|
Wheat (purchased by UK Millers, September- November 1993) |
129 |
127 |
- |
- |
2 |
TOTAL |
611 |
609 |
- |
- |
2 |
Table 2: Results of 1994 survey of wheat and barley for ochratoxin
A (Phase 2) |
Sample type |
Number of samples analysed |
Number of samples containing OA in the range (µg/kg) |
<1 |
1-5 |
5-10 |
>10 |
|
Barley at harvest |
150 |
143 |
6 |
- |
1 |
|
Barley (1993 stored ) |
50 |
40 |
8 |
1 |
1 |
|
Wheat (purchased by UK Millers, in 1994) |
250 |
228 |
15 |
3 |
4 |
TOTAL |
450 |
411 |
29 |
4 |
6 |
Interpretation
Ochratoxin A was not detected in the majority (96 percent) of all
samples. The results of the survey indicate that ochratoxin A does not
appear to be prevalent in UK barley and wheat collected at harvest. OA was
detected in several stored wheat and barley samples, but of these samples
only 6 wheat and 1 barley sample contained OA at concentrations above 10µg/kg.
The COT advised that OA should be considered a genotoxic carcinogen and
recommended that the levels of OA contamination should be reduced to the
lowest technologically achievable.
The occurrence of OA appears to be associated with storage conditions of
cereals. In the light of this, MAFF will contact the Industry to discuss
methods of preventing elevated concentrations of OA found in a few
samples, especially in stored grain.
Contact Point
Further information can be obtained from:
Dr Martin Slayne
MAFF, Joint Food Safety and Standards Group
Food Contaminants Division
Room 207 Ergon House c/o Nobel House
17 Smith Square
London SW1P 3JR
Tel: +44 (0)20 7238 6222
Fax: +44 (0)20 7238 6591
Return to Index to Surveillance Information Sheets, 1995 page
Go to top of page
These pages were last updated on 1 October 1996
