Checking for due diligence on mycotoxins

The UK Malting Industry is committed to ensuring that its products conform to the highest quality and safety standards. It is therefore working to reduce levels of contaminants, which are sometimes unavoidable in agricultural crops, to levels which are as low as possible.

Mycotoxins are contaminants which can occur in cereal grains as a result of mould infection. This can occur both in the growing crop (Field fungi) and during grain storage (storage mould). There are many different mycotoxins. In the UK, the Malting Industry has developed systems to safeguard its raw materials and its products against mould infections and mycotoxin production. Only the highest quality barley is selected. Harvested grain is dried to around 12% moisture for long term storage. This is too dry to allow most moulds to flourish. Best practice guidelines have been developed for drying and storing malting barley, in conjunction with the UK's Home Grown Cereals Authority. (HGCA Grain Storage Guide, Second Edition 2003)

Representative sets of barleys and malts are analysed every year to check for the presence of mycotoxins and other potential contaminants. These tests show that levels of mycotoxins in UK malts are very low.

Aflatoxins

In the EU there are legal limits of 4m g/kg (for total aflatoxins) and 2 m g/kg (for one specific aflatoxin, B1) in cereals. However, the moulds which produce aflatoxins grow best in conditions which are warmer than those generally encountered in the UK, thus aflatoxins are rarely found in cereals grown in the UK. The MAGB has monitored levels of aflatoxins in malting barleys from successive harvests, and the levels found have always been well below these legal limits. No samples contained detectable B1 . Most samples contained either no detectable aflatoxins or less than one tenth of the legal limit. (source BRi)

Ochratoxin A

The moulds which produce this mycotoxin do not infect growing barley in Europe. They can develop on harvested grain, but only if it is stored in damp, conditions, and particularly if the grain temperature is high. The minimum moisture content to support fungal development was considered to be 18% moisture, but it is now thought to be just above 14.5% moisture. This is a significant change in understanding, and means that storage practices might have to change outside the UK. In the UK malting barley is routinely dried to about 12% moisture before storage. This is too dry to allow ochratoxin- producing moulds to flourish. The legal limits for ochratoxin A in cereals in the EU are 5m g/kg for raw grain and 3m g/kg for processed grain (which includes malt).

Malting barleys have been monitored for ochratoxin A content for many years. These surveys continue to show that most UK malting barleys contain no detectable ochratoxin A. Prompt checking of the crop is done as soon as possible after harvest each year. The results below of 'due diligence' checking by MAGB each year show the OTA tests carried out on the barley crops from 2001 to 2004

In addition to the tests for mycotoxin on barley at harvest, tests are also carried out on the barley later in the year, to check that no problems have arisen with the formation of storage fungi, and the resultant mycotoxins that can be produced from storage bad practices. As an additional check, tests are also carried on on finished malts, which can be seen below.

Note: Some of the above surveys were carried out prior to the current EU limit of 3mg / kg for OTA in Malt being set in 2002. The results highlight the historically low levels of OTA found in UK malts.

Fusarium mycotoxins

Fusarium moulds are widespread on growing crops and normally do little damage to the plant. However, under some conditions they can produce a number of toxins from the trichothecene group, including deoxynivalenol (DON), nivalenol (NIV) and zearalenone (ZEA). Currently there are no legal limits for these compounds in the EU, although a "action limits" of 1250 m g/kg (for raw cereals) and 500 m g/kg (processed grain) have been proposed for DON.

The levels of Fusarium toxins in malt can be controlled by good farming practices producing good quality barley, then by grain inspection at intake from farm, by efficient drying and good storage conditions (for both malt and barley) and by attention to hygiene in the malting plant.

RESULTS OF DON TESTING

DON levels have been tested for MAGB over many years on finished malt, to ensure 'due diligence' as the data below shows for malts tested from 1999 (yellow points) to 2003 (red points) demonstrates:

RESULTS OF NIVALENOL  TESTING

Results of tests on UK grown malting barley purchased by UK maltsters in crop years 2002, 2003 and 2004 is shown below

Tests have also been carried out for NIV on UK malt made from UK malting barley for several years as part of the MAGB due diligence testing system, the results of which are shown below in chart form.

RESULTS OF ZEARALENONE TESTING

The tests results for the due diligence cross checking for the presence of Zearalenone as shown below for barley then malt:

The results detailed above were mainly carried out for MAGB by BRi at Redhill,UK, as part of the annual HGCA funded work on the food safety of cereals in each crop year. Some results were supplied by IFBM at Nancy in France when the UK has submitted samples as part of Euromalt survey work.

For a workbook, showing all the results of MAGB mycotoxin survey work, including testing for OTA, DON, 3-AcDON, 15-AcDON, NIV, HT-2, T-2, Fusarenone-X, Neosolaniol, Diacetoxyscripenol, ZEA , Citrinin and Cytochalsin CLICK HERE.

The bar at the bottom of the page that opens will take to to the test results for each substance shown.

The Maltsters Association of Great Britain
31B Castlegate, Newark, Notts, NG241AZ.
Phone 01636 700781, Fax 01636 701836