Sainsbury's like-for-like sales including fuel fell 2.4% in the first quarter of 2014, according to the company's trading statement.
Like-for-like sales excluding fuel were down 1.1%.
Total retail sales at Sainsbury's were up 1% in the first quarter of 2014, the supermarket has announced.
- Tesco reported its worst sales figures for 40 years last week.
- The British Retail Consortium reported food sales in the UK are declining for the first time in six years by 0.2%.
- A recent survey from The Institute of Grocery Distribution estimates that between 2012 and 2017 sales at superstores will grow by just 6%, approximately £3.3bn.
- Over the same period, takings at convenience formats are expected to rise by more than 28%.
- Discount retailers will see a growth of 65% and online is expected to rise by a whopping 97.7%.
Supermarket giant Sainsbury's are expected to announce a drop of between 1-1.5% in their life-for-like sales later this morning.
The news comes as chief executive Justin King bows out after 10 years in charge of the supermarket.
This would be the second consecutive quarter of falling sales for Sainsbury’s, which had previously enjoyed nine years of unbroken sales growth under Mr King.
City experts have warned the retail giant has a "tough year ahead".
However, the "Big Four" supermarket cleared £1bn in annual sales for the first time last year and announced plans to expand its convenience store business.
Sainsbury's has recalled some of its own-brand olives after discovering glass in "a small number of jars".
The supermarket said they had issued a small-scale product recall as a "precautionary measure" after receiving complaints from customers.
A spokeswoman said anyone with jar with a best before date of 13/1/17 should return the product and would get a full refund.
Outgoing Sainsbury's boss Justin King has capped his decade in charge of the supermarket by announcing a ninth successive year of annual profits growth, but warned of tough times ahead.
Underlying profits before tax rose 5.3% to £798m in the year to March 15, but like-for-like sales for the period were almost flat, edging up 0.2%.
Mr King, who will hand over the reins of the grocer to commercial director Mike Coupe in July after 10 years in charge, said a focus on quality, affordable own-brand products had helped Sainsbury's succeed in a tough retail environment.
But he warned: "While the general economic outlook is showing some signs of improvement, conditions in the food retail sector are likely to remain challenging for the foreseeable future as customers continue to spend cautiously."
Sainsbury's says it has immediately withdrawn 500g bags of SO Organic sultanas from its shelves after "low levels of salmonella were found during routine testing".
Food safety is our top priority so we immediately took this product off display and, as a precautionary measure, we are asking customers who have bought these sultanas to return them to their nearest Sainsbury’s store where they will receive a full refund.
We apologise to customers for any concern and inconvenience this causes.”
Sainsbury's is withdrawing SO Organic Sultanas as a precaution after routine testing found salmonella.
The recall applies to 500g bags, according to the Food Standards Agency.
Advice on the FSA website reads: "If you have bought the above product, do not eat it. Instead, return it to the store where you bought it for a full refund.
"No other Sainsbury’s Supermarkets Ltd products are known to be affected."
Although usually associated with meat, seafood and eggs, salmonella can also be found in fruit and veg that has been washed in dirty water.
Supermarket Sainsbury's has warned the market is growing at its slowest pace for nearly a decade as it broke a nine-year run of underlying sales growth.
The group revealed that like-for-like sales excluding fuel slumped 3.1% in the 10 weeks to March 15, marking a sharp reversal of recent fortunes and the first fall after 36 consecutive quarters of rising sales in a row.
Outgoing boss Justin King said the group came up against tough comparatives from a year earlier when it outperformed many rivals amid the horsemeat scandal and benefited from the timing of Mother's Day and Easter trade.
But he stressed that the market was facing tough conditions in the latest downbeat trading statement from one of the "big four" players as cost-conscious consumers increasingly turn to discounters such as Aldi and Lidl.
He said: "The market is now growing at its slowest rate since 2005, with falling food inflation in particular benefiting customers."
He added: "Although some economic indicators are showing an improvement in the health of the economy, we expect the outlook for customers to continue to be challenging for the coming year."