Over 20 per cent of food items served in restaurants and fast food outlets across the country have been found to be substandard or adulterated, according to government data.

Out of 46,283 food samples including milk, milk products, edible vegetable oil and spices tested at various government laboratories during 2013-14, as many as 9,265 samples were found to be adulterated and misbranded.

Uttar Pradesh reported the highest number of such cases in 2013-14, with a total of 2,930 vendors being prosecuted and as many as 1,919 of them convicted. A total penalty of more than Rs 4.47 crore was imposed on offenders in the state.

In 2012-13, a total of 2,551 cases were registered and there was conviction in 1,010 cases. Penalty amount of over Rs 3.70 crore was imposed on offenders.