Two bacon rashers can contain more salt than 12 packets of ready salted crisps, an investigation has found.
A nutritional review of 171 types of bacon sold in British supermarkets also revealed nine out of 10 were saltier than seawater.
Marks and Spencer’s Select Farms British Dry Cured Unsmoked Middle Bacon was the worst culprit, with two rashers serving up 4.2g of salt.
That is the equivalent of 12 bags of Walkers Ready Salted Crisps, which have 0.35g per pack, and two-thirds an adult’s entire daily recommended salt intake (6g).
The retailer’s ‘Thick Rashers Thick Cut Smoked Back Bacon’ was also crammed with the mineral. It served up 2.8g of salt in two slices, more than quadruple the amount found in McDonald’s medium fries (0.62g).
Campaign group Action on Salt, behind the review, has demanded the government introduce a salt tax, following the success of a sugar levy on soft drinks.
It said the results of its investigation were ‘shocking’ and clearly show manufacturers are not abiding by Public Health England’s voluntary salt reduction scheme.
Companies were asked to meet average and maximum targets for salt content per 100g in various types of foods, including canned vegetables and curry pastes.
M&S scooped the top three saltiest bacon products in Action on Salt’s survey, followed by Lidl.
The budget supermarket’s Warren and Son’s Thick Cut Back Bacon Smoked was crammed with 3g of salt per two rashers – triple that found in a Burger King Hamburger (1g).
And Tesco’s Smoked Back Bacon Rashers Thick Cut served up 2.8g of the mineral in two rashers – the equivalent of seven packets of ready salted crisps.
The Co-op’s Irresistible Air Dry Cured Smoked Back Bacon Rashers were not much better, with 2.5g of salt per two cuts of meat.
Bacon is soaked in salt water during the curing process to give the meat its flavour, preserve it and give the rashers their colour.
Adding salt makes the meat an unfriendly environment for bacteria to grow and, as a result, bacon has a much longer shelf life than fresh pork.
But Action on Sugar’s survey showed that bacon could easily be made with far less of the mineral than it currently is.
The least salty bacon overall was The Co-operative Reduced Fat Unsmoked Bacon Medallions, with just 0.9g in every two rashers.
M&S’ Select Farms British Dry Cured Thin & Crispy Smoked Streaky Bacon contained even less at 0.5g, but the rashers were much smaller.
The campaign group also found that bacon products labelled with ‘reduced salt’ did not necessarily have the lowest levels of the mineral.
Lidl Birchwood Smoked Reduced Salt Back Bacon had 2.1g per 100g, compared to Waitrose Free Range Unsmoked Back Bacon (1.5g).
Action on Salt slammed some supermarkets for using a loophole to make it seem as though their bacon was less salty than it was.
Some chains choose to provide the salt content for their raw rashers, as opposed to cooked ones. When the meat is cooked is becomes roughly 30 per cent saltier.
Salt found in processed foods contributes to high blood pressure, a major risk factor for heart disease (CVD).
Worldwide, CVD causes an estimated 31 per cent of deaths, and 17.9million each year, according to estimates.
Having high blood pressure puts people at risk of CVD because it puts extra strain on the blood vessels and heart.
The condition, known as hypertension, affects more than one in four adults in the UK, and one in three in the US, official statistics show.
Consuming too much salt raises the amount of sodium in the blood, causing fluid retention inside the body which results in higher blood pressure.
The investigation revealed all but two of supermarkets provided colour-coded nutritional information on the front of bacon packaging.
Tesco and Iceland were the only two not to do so, ‘putting their customers at a disadvantage’, according to Action on Sugar.
Sonia Pombo, campaign manager for Action on Salt said bacon was the biggest contributor to salt after bread in the UK.
She added: ‘It’s shocking to learn that food manufacturers are still ignoring the voluntary salt reduction targets and putting profits before the health of the nation.
‘We have seen great success with the soft drinks industry levy in driving reformulation, and the government must now consider doing the same for key contributors of salt in UK diet, such as bacon. This way, everyone’s health benefits, including the socially deprived.’
Graham MacGregor, professor of cardiovascular medicine at Queen Mary University of London and chair of the campaign group, said the time was up for food firms who ‘put profit before the nation’s health’.
He added: ‘The Prime Minister must be reminded that just one-gram reduction in population salt intake prevents more than 4,000 premature deaths per year in the UK and costs next to nothing to implement.
‘For many years, food manufacturers have been allowed to put profits before the health of our nation and we now urgently need Boris Johnson’s no nonsense approach to get things done with an ‘oven ready’ mandatory salt reduction programme for all products for 2020.
‘This will save thousands of people suffering and dying unnecessarily, and at the same time provide huge cost savings to the NHS.’
Action on Salt’s survey looked at the salt content of bacon in every 100g and per two rashers.
Some bacon products ranked poorly because they had large rashers which contained a lot of salt because of their size, while others had a higher ratio of salt to meat, meaning they had more salt per 100g.