Big beer drinkers who down as much as two pints a day may be exposing themselves to harmful levels of fungal toxins, a study has found.

Researchers analysed the amounts of mycotoxins produced by microscopic fungi in 154 brands of beer sold in Europe.

They found that their levels were low enough not to pose a risk to the average beer lover. But anyone quaffing a litre or more of beer a day could be consuming a potentially hazardous quantity of the substances.

The two most abundant toxins, deoxynivalenol, or DON, and HT-2, appeared respectively in 60 per cent and nine per cent of the samples tested.

For people drinking a lot of beer, exposure to these toxins was “approaching or even exceeding” the maximum tolerable daily intake (TDI) levels set by the Scientific Committee on Food that advises the European Commission.

Lead researcher Houda Berrada, from the University of Valencia in Spain, said: “Considering only consumption amounting to one litre a day of the brands of beer that showed the highest contamination levels, intake of deoxynivalenol would be equivalent to 60 per cent of the maximum TDI and the safety levels for HT-2 would be exceeded.”

However the researchers, whose findings appear in the journal Food Chemistry, point out that someone drinking a litre of beer a day would probably experience liver problems before suffering symptoms of fungal toxin poisoning.

The study also showed how beer consumption per head varied between European countries. People in the Irish Republic topped the beer drinking table, with each person consuming an average of 142.8kg per year – or around 140 litres.

Next came the Czech Republic (136.6kg per year) and Austria (107kg per year).

The average European citizen drank 70.1kg of beer a year. A litre of beer weighs 0.99kg.