Figures show shoppers are paying 10.6% more for food than a year ago.
Overall store price inflation accelerated to 5.7% in September from 5.1% in August, another record high since the British Retail Consortium-Nielson IQ index began in 2005.
Food price inflation soared from 9.3% to 10.6% last month, boosted by the war in Ukraine, which continues to push up the price of feed, fertilizer and vegetable oil and affect especially products like margarine.
Fresh food products cost a record 12.1% more than last year, up from 10.5% in August, the highest rate on record for the category.
Inflation for staples such as pasta and tinned tomatoes hit a record 8.6%, up from 7.8% the previous month, the fastest rate of increase in the category.
While the summer drought reduced some crops, other produce benefited from the extended sunshine, leading to a drop in prices for fruits such as strawberries, blueberries and tomatoes.
Non-food inflation rose to 3.3% from 2.9% in August, largely driven by larger hardware, DIY and garden products hit by higher transport costs.
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Helen Dickinson, chief executive of the British Retail Consortium, said: “Retailers are struggling with huge cost pressures from the weak pound, rising energy bills and global commodity prices, high costs of transportation, a tight labor market and the cumulative burden of government-imposed costs.
“And with business rates set to rise by 10% next April, narrow retailers face an extra £800m in unaffordable tax rises.
“The government must urgently freeze the business rate multiplier to give retailers more room to do more to help households.”
Mike Watkins, NielsenIQ head of retail and business intelligence, said: “With food and home energy prices continuing to rise, it’s no surprise that NielsenIQ data shows that 76% of consumers say they expect be moderately or severely affected by the cost of living crisis over the next three months, compared to 57% in the summer.
“So households will be looking for savings to help manage their personal finances this autumn and we expect shoppers to be more cautious about discretionary spending, increasing pressure on the retail sector.”