High salt warning on a typical supermarket barbecue meal

A meal of a hotdog with mustard, a burger with cheese and barbecue sauce, a piece of marinated meat, a helping of coleslaw and potato salad and plain crisps with dips can add up to 12.11g of salt, Consensus Action on Salt and Health (Cash) said.

The recommended daily maximum for an adult is 6g a day.

Cash tested 603 barbecue food products including burgers, sausages, crisps, salads and dips from seven supermarkets and brands.

The meal with the lowest amount of salt contained just 2.75g, revealing a significant difference in salt content across similar-looking products, Cash said.

A shopping basket of barbecue items from each of the supermarkets could easily exceed 6g of salt, the study found.

A typical barbecue meal from Tesco, Asda and Morrison's each contained more than 9g of salt, with Tesco's adding up to the highest at 9.27g.

In comparison, a barbecue meal from Sainsbury's contained less than 4g of salt.

Morrison's Best Sea Salted Handcooked Crisps dipped into Discovery Hot Salsa Dip contained 15 times more salt than Kettle Chips No Added Salt and Morrison's Tomato Salsa, Cash said.

The study also found 174 of the items tested did not have front-of-pack labelling, more than 100 products had no information about salt per portion and 22 products had no salt information at all.

Asda and Marks & Spencer products used the clearest labelling, combining guideline daily amounts (GDAs) and traffic lights. Waitrose labelling was the least consistent and the most difficult to analyse of all the supermarkets, Cash said.

Cash chairman Professor Graham MacGregor, from the Wolfson Institute of Preventive Medicine, said: "The fact that some manufacturers can keep the salt content right down in these foods highlights how unnecessary it is for the rest to have such a high salt content.

"It is the very high levels of salt that are added to our food that puts up our blood pressure and leads to thousands of people needlessly dying of strokes, heart attacks and heart failures every year. We urge these companies to reduce their salt content immediately."

A Waitrose spokeswoman said: "We are currently updating packaging to include GDAs within the traffic light labelling panel as recommended by the FSA and intend to extend this to a wider range of products."

Tesco said: "Tesco has removed over 632 million teaspoons of salt from products in the UK since 2006. All of our products carry clear front-of-pack labelling and this includes guidance daily amounts (GDAs) on salt, helping customers make an informed decision on the products they consume."