While traditional pesto is made with four key ingredients - basil, pine nuts, parmesan and olive oil - it seems the UK high street has been adding in surprising extras.
A new analysis of supermarket own-label pesto found some jars from supermarkets contain ingredients like bamboo fibres, glucose syrup (sugar) and cashew nuts.
Nikki Stopford, Director of Research at Which?, said: “Pesto has become a staple food in the UK but our research shows that many shoppers may be getting more than they bargain for when it comes to the pesto they are buying - and not necessarily in a good way.”
Which? nutrition experts reviewed the contents of 12 different 190g jars of pesto from supermarkets including Asda, Co-op, M&S, Morrisons, Sainsbury’s, Tesco and Waitrose.
The standard pestos analysed were all made in Italy and contained between 42-49% basil, but they also contained cheaper ingredients in place of the traditional elements such as cashew nuts instead of pine nuts, or a mix of both. In some jars, olive oil was substituted with sunflower oil, and parmesan with less expensive grana padano and pecorino romano cheeses.
All standard pestos, apart from Waitrose (£1.35), used thickeners such as potato flakes, nut flour, vegetable or even bamboo fibres. Sainsbury’s (£1.00), Tesco (£1.00) and Co-op (£1.19) standard pestos also contained sugar and Co-op, Morrison’s (£1.00) and Tesco listed water as an ingredient.
The premium pestos reviewed were all labelled ‘alla Genovese’ and by definition have to contain the traditional ingredients of basil, olive oil, pine nuts and parmesan. The five examined all contained between 38-50% basil, plus the requisite extra-virgin olive oil and parmiggiano reggiano (parmesan) as well as pine nuts.
However, even the premium pestos contained some surprising extras. The Morrisons (£1.95), Sainsbury’s (£1.50) and Tesco (£2.00) premium alla Genovese pestos all contained vegetable or bamboo-fibres as thickeners and added sugar, while Morrisons Pesto alla Genovese also listed water as an ingredient.
Which? said the investigation shows price doesn’t necessarily mean your pesto will be free of less-expensive and possibly unwanted ingredients. As such, it urged consumers to always check the ingredients list.
The analysis found the products with the most authentic and traditional ingredients were Asda Extra Special Genovese Basil Pesto (£1.39) and Waitrose 1 Pesto alla Genovese (£2.70).
Nikki Stopford concluded: “Our advice is not to assume that all pesto contains the same traditional ingredients. Check the ingredients list if authenticity is important to you, or if you are trying to avoid certain contents, such as added sugar.”