It may shock you to find out that there is alcohol lurking in food we consider to be booze-free. 

From bread and fruit juice to yoghurt and soy sauce, some foods can even contain more than some low-alcohol beers. 

In fact, just one banana can contain roughly 0.2 per cent ABV (alcohol by volume), according to Abbeycare, a rehab clinic. Ripe bananas may have double that.

Surprisingly, American-style burger rolls are one of the worst offenders, with up to 1.28 per cent ABV. 

According to a 2016 German study published in the Journal of Analytical Toxicology, a ripe banana with spots on it contains as much as 0.4 per cent alcohol. The study also found yoghurt to contain 0.02 per cent ABV, a burger bun to contain 1.28 per cent, apple juice 0.026 per cent, orange juice 0.073 per cent and soy sauce 2 per cent alcohol

Wheat and rye bread contains less at 0.29 per cent ABV. That is according to a 2016 study published in the Journal of Analytical Toxicology.

Registered dietitian Dr Duane Mellor, of Birmingham’s Aston University, said: ‘During the proving process bread will have yeast, which ferments the carbohydrates and produces alcohol.’

Any fermented foods are likely to contain traces of alcohol, according to Dr Mellor.

Similarly, fruit juice can have hidden ethanol. 

The 2016 study also showed grape juice contains 0.086 per cent ABV, orange juice 0.073 per cent and apple juice 0.026 per cent.

And a cherry yoghurt has 0.02 per cent ABV.

 A ripe banana with spots on may have more alcohol in it at about 0.4 per cent ABV 

Just like beer, bread contains yeast, water and grains but bread doesn’t contain hops. The yeast ferments the carbohydrates and produce alcohol, but most of this alcohol is evaporated during the cooking process

Any item that is less than 0.5 per cent ABV is considered to be ‘alcohol-free’ in the UK, while 1.2 per cent is categorised as ‘low alcohol’. 

Therefore, on their own, these food and drink options are either alcohol-free or low alcohol.

Fermentation — when bacteria or yeast breaks down carbohydrates into sugars which turns into an acid or alcohol — is how alcohol ends up in these items. 

For example, a banana ferments when airborne yeast reacts with the sugar content of the fruit, which causes it to ferment into alcohol and carbon dioxide. 

And fruit juices are prone to fermentation for the same reason. When juice is left in a warm environment airborne yeast converts the sugars in the juice into alcohol. 

Meanwhile, soy sauce is fermented as part of the manufacturing process.  

Soybeans, wheat, salt and water are combined and fermented, which causes wheat starches to break down into sugars and turn into alcohol. 

While much of this alcohol evaporates during production, the product still contains 1.5 per cent to 2 per cent ABV, which adds to its flavour.