Rabbits, piglets and mice are being killed when heavily pregnant, injected with deadly bacteria and bled to death by food firms testing fashionable superfoods, it has emerged.

The experiments involve food giants including KitKat maker Nestle, Unilever – the owners of PG tips – Knorr, Hellmann’s and Yakult, the maker of probiotic drinks.

Food companies stress that animals are used as little as possible and are cared for to the highest standard.

According to the British Union for the Abolition of Vivisection (BUAV) animals including rabbits, rats, mice and piglets suffered as a result of the growing fascination with so-called ‘superfoods’

But the campaign group that uncovered details of the experiments, which were carried out over the past two years, claim that most were not done to assess the safety of the food.

Instead, they say the tests appear to have been carried out to allow the companies make health claims about their products.