Food inflation jumped to 9.13 per cent for the week ended September 17 from 8.84 per cent in the previous week, mainly due to a rise in prices of potatoes, pulses and poultry.Finance Minister Pranab Mukherjee has termed the rise in food inflation as an area of grave concern.As per Wholesale Price Index (WPI) data released by the government today while, prices of onions eased marginally during the week, gram, masoor, arhar, urad and poultry rates firmed up on an annual basis,Potato prices, too, firmed up by about 15 per cent on an annual basis. However, as a whole, inflation in the fruit and vegetable segments eased during the week under review vis-a-vis the same period last year.In the week ended September 10, food inflation had declined to 8.84 per cent from 9.47 per cent in the previous week.