Food inflation remained in the negative zone for the fourth week in a row, at minus 1.03 per cent for the week ended January 14, on account of cheaper vegetables. Food inflation, as measured by the Wholesale Price Index, had stood at minus 0.42 per cent in the previous week, and above 17 per cent in the corresponding week of 2011.According to official data released, today, onion prices plummeted 79.1 per cent, year-on-year, for the week under review, while potato prices fell 22.46 per cent. Prices of wheat dropped 3.37 per cent. Overall, vegetables were 47.06 per cent cheaper during the week under review, from the same period last year. However, other food products, led by protein-based items, became more expensive on an annual basis.