The latest BRC-Nielsen figures show that overall shop prices rose 0.1 percent in August, entering inflationary territory for the first time since April 2013.
Food inflation jumped to a seven-month high of 1.9 percent in August.
The lowest rate of deflation for non-food items for more than five years also led to the return of shop price inflation, according to the shop price index.
Non-food price deflation eased back further to 1 percent in August, down from 1.4 percent in July and the lowest level since April 2013, as strong demand for summer products earlier in the season reduced the need for discounting.
The figures come as concerns grow that consumers may face a food price shock over the coming months.
The Centre for Economics and Business Research (CEBR) said this week that food prices could rise by at least 5 percent as a result of spells of unusually cold winter weather and the summer heatwave in 2018.
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