Tesco has delisted all of Bertolli's olive oil spreads amid industry speculation that Unilever and Tesco are once again at loggerheads over price.

The three Bertolli spread packs that Tesco used to stock 500g and 1kg packs of the standard spread and a 500g pack for the lighter variant started to disappear from shelves at the end of August, according to data from BrandView. Two types of Bertolli olive oil, which used to be owned by Unilever but is now owned by Spain's Grupo SOS, were also delisted recently.

The delisting means the number of Bertolli products stocked by Tesco has almost halved over the past three months, from 13 in June to seven now all of them cooking sauces. The only branded olive oil spreads available to buy from Tesco online this week were Benecol olive spread and Flora Pro-activ with olive oil (also owned by Unilever) as well as three types of own label.

Tesco and Unilever did not respond to requests for comment, but sources said the delisting was likely to be down to price disagreements rather than Tesco deciding it did not want to stock Bertolli products.

Commodity prices for vegetable oils have spiked in recent weeks, putting suppliers of oils and oil-reliant lines under increasing pressure to pass on higher prices. "They [Unilever] probably asked for a price increase and Tesco didn't agree," said one industry executive of the delisting.

Over the past 90 days, Sainsbury's has increased the price for 500g packs of Bertolli spread by 24p, from £1.46 to £1.70, with prices at Waitrose also up to £1.70, from £1.56 [BrandView]. Prices at Morrisons and Asda have remained flat since June, at £1.68. Tesco sold Bertolli spread for £1 back in June.

Last year, Tesco delisted Unilever's Knorr Ragu range after the company asked for a price increase, but reinstated the range a few months later. The same is expected to happen with the spreads and olive oils. "Bertolli is the market leader in olive oil spreads, so delisting it is a big deal," said the executive.