Annual food inflation rose slightly to 10.86 per cent for the week ended August 21, after the previous, two-week decline, despite a fall in vegetables prices. Food inflation had softened to 10.05 per cent for the week ended August 14, from 10.35 per cent in the previous week. On a yearly basis, potatoes became cheaper by over 51 per cent, while vegetables overall saw a decline of 9.9 per cent. Onion prices fell 8.97 per cent, official data released today showed. Cereal prices, however, rose 6.76 per cent, driven mainly by higher prices of pulses, rice and wheat, compared to the same period last year. Milk prices soared 18.22 per cent, and fruits became dearer by 9.27 per cent during the week, over the same period last year.