It’s meant to be a simple mix of basil, pine nuts, parmesan and olive oil. But the pesto in your cupboard could have an added ingredient – bamboo.
Manufacturers eager to cut costs, and battling a shortage of pine nuts and olives, are adding a range of unusual thickeners to the classic Italian sauce.
Worse still, it is producers in Italy that are guilty of butchering the recipe, according to consumer group Which?.
Olive oil was replaced with sunflower oil, and parmesan with less expensive Grana Padano and Pecorino Romano cheeses (stock image)
A test of 12 own-brand standard and premium pestos made in the country found a range of additional ingredients.
All standard pestos were made with between 42 per cent and 49 per cent basil, but also contained cheaper alternatives such as cashew nuts instead of pine nuts or a mixture of the two.
Olive oil was replaced with sunflower oil, and parmesan with less expensive Grana Padano and Pecorino Romano cheeses. And all of the standard pestos, apart from Waitrose’s £1.35 version, used thickeners such as nut flour and even bamboo fibres.
Standard pesto from Sainsbury’s and Tesco, both £1, and the Co-op’s £1.19 version also contained sugar.
The most expensive standard pesto, from Marks & Spencer and costing £2.10, contained carrot fibres.
It might be assumed that premium pestos, which are labelled ‘alla Genovese’ relating to the sauce’s origins in Genoa, would be true to the traditional recipe – but this was not the case.
All of the standard pestos, apart from Waitrose’s £1.35 version, used thickeners such as nut flour and even bamboo fibres (stock image)
All had generous amounts of basil as well as extra-virgin olive oil, parmesan and pine nuts.
However, there were also some surprising extras. Morrisons, Sainsbury’s and Tesco all added sugar as well as vegetable or bamboo fibres to thicken the product.
The products with the most authentic ingredients were Asda Extra Special Genovese Basil Pesto (£1.39) and Waitrose 1 Pesto alla Genovese (£2.70).
The consumer watchdog said its investigation showed that a higher price did not necessarily mean that the product would be free of unwanted ingredients and urged shoppers to check the labelling. Which? director of research Nikki Stopford said: ‘Our advice is not to assume that all pesto contains the same traditional ingredients.’
An M&S spokesman said carrot fibres helped bind the basil and oil together, improving the product’s shelf life.