BERLIN: German authorities are investigating possible large-scale fraud by organic egg producers amid increased concern over food industry practices following Europe's horse meat scandal.

The northern state of Lower Saxony, a major agricultural hub, has launched probes of some 150 farms suspected of wrongly selling eggs produced by hens kept in overcrowded conditions under the organic label.

Two other states are investigating a further 50 farms.

"If the accusations (against the farms) are found to be true, then we are talking of fraud on a grand scale: fraud against consumers but also fraud against the many organic farmers in Germany who work honestly," German Farm Minister Ilse Aigner said in a statement on Monday.

She urged regional governments to ensure the full implementation of tough German and EU laws on organic food production, adding that consumers must be able to have full confidence in the labelling of products.

Organically produced eggs cost some 10 cents more than those produced under standard industrial conditions.

Christian Meyer, farm minister in the newly appointed Lower Saxony government, vowed to take a tough line on any farms found to have broken the law.

Organic food is a huge industry in environmentally-conscious Germany, where many consumers are willing to pay extra for eggs, meat, vegetables and other products they believe have been produced organically.

The suspicions of organic egg fraud coincide with the discovery that horse meat was labelled as beef in processed food sold around Europe. The scandal has triggered recalls of ready meals and damaged confidence in the continent's food industry.

Two years ago a European Union-wide health alert was sparked when German officials said animal feed tainted with dioxin had been fed to hens and pigs, contaminating eggs, poultry meat and pork at affected farms.