Food inflation rose marginally to 17.97 per cent for the week ended February 6 on account of rising prices of potatoes and onions. The wholesale price-based food inflation rose for the fourth consecutive week. In the previous week it stood at 17.94 per cent. Potato prices were up 57.67 per cent from last year's level, while onions were dearer by 29.92 per cent.The inflation for primary articles, which include food and non-food items in raw form, increased to 16.23 per cent during the week from 15.75 per cent a week earlier. Yesterday, Finance Minister Pranab Mukherjee had saidrising inflation is a matter of concern but exuded confidence it would ease in the next few months. Wholesale price-based overall inflation rose to 8.56 per cent in January, shooting past the RBI's forecast of 8.5 per cent for this fiscal end.