Food prices are never far from the headlines and are likely to have further profound effects both on consumer behaviour and retailer strategy.

According to a report published this week from Deloitte, food prices have been increasing substantially for the first time since the 1970s. Since 2000, the prices of maize and rice have doubled, while the price of wheat has tripled.

There are already signs of higher food prices leading to more people buying lower-priced private-label and discounted products, as well as shopping at the discount retailers. Yet shoppers are also moving away from eating meals in restaurants and bars, which could also produce an opportunity for grocers.

Retailers must prepare for various scenarios, including the worst, with continued rises in commodity prices and slowing consumer spend. They also have to judge how much of the costs to absorb in order to stay ahead of competitors and maintain healthy relationships with suppliers.

But, while price inflation is a key concern, Tesco’s results this week show that there is worry on the non-food side too. Tesco – often regarded as a bellwether for the industry – has sparked fresh fears about the extent of a downturn as it revealed its non-food business has begun to be affected.

Tesco’s growth in general merchandise ranges such as clothing, furniture and electricals – the driver of much of its expansion in the past 10 years – has slowed. Sir Terry Leahy admitted: “Our rate of growth in non-food has eased as consumers have been more cautious with their spending.”

Non-food makes up between 20 and 25 per cent of Tesco’s sales and it is one of the big growth areas for the retailer. But, as the property market continues to slow, consumers will also continue to cut back on non-food items.

The slowdown in non-food must be being felt at other grocers and next week’s Sainsbury’s results will probably tell the same story. Tesco, Sainsbury’s and Asda have all laid out bullish plans for their non-food operations but, in the present climate, these may change.

Their propositions are strong because their non-food ranges offer value, but if shoppers don’t want to make unnecessary purchases, they won’t just buy items because they are cheap. All eyes will be on Sainsbury’s next week.