Leading food companies have been accused of conducting "cruel and unnecessary" animal experiments to demonstrate the health benefits of their products.
The animals, including rabbits, rats and piglets, suffered as a result of the growing fascination with so-called "superfoods", according to the British Union for the Abolition of Vivisection (BUAV).
Major names including Unilever, Nestle and Yakult had allegedly been been involved in "sickening" tests, it was claimed, and all the work identified in research papers by the animal welfare group was said to have been published in the last two years.
One experiment linked to Unilever tested the infection-fighting properties of Lipton tea on one-month-old piglets.
Ninety-six animals were housed in isolation and fed tea for six days before being infected with E.coli bacteria to induce diarrhoea, it was claimed. Eight piglets died and a number of others developed skin abnormalities and behavioural problems, said the BUAV.
For another experiment investigating a Yakult yoghurt drink, rats were starved for 20 hours then force-fed probiotic bacteria through a steel tube, the group added. After two hours the animals were forcibly fed a hydrochloric acid solution to damage their stomachs. The rats were left to suffer for an hour before being killed and dissected, it was alleged. Nestle was accused over a third test looking at the anti-oxidative and anti-inflammatory properties of Goji berries.
Mice were fed a water-soluble powder called Lacto-Wolfberry consisting of Goji berries and skimmed milk. After seven days, a chemical irritant was injected directly into the rectums of the mice to induce colon disease, it was claimed. Due to the pain, the mice stopped eating and had to be force-fed the Lacto-Wolfberry preparation before being killed, according to the BUAV.
Dr Katy Taylor, head of science at the BUAV, said: "The public will be shocked to learn that these well-known and familiar high street brands are involved in sickening experiments on animals. It is unacceptable that animals should be made to suffer by companies in an effort to make 'health benefit' claims about their products. The BUAV is calling on all food giants to immediately stop experimenting on animals to test food products and ingredients by switching to humane alternatives or using existing data."
A Unilever spokeswoman said the company committed itself to no animal testing for tea or tea-based beverages in January 2011. She added: "We have upheld this since and therefore presumably these studies referenced are old."
A Nestle spokesperson said: "Nestle does not use animal testing to develop the conventional foods and drinks that are sold in shops and supermarkets, such as coffee, tea, cereal and chocolate. The Nestle study that the BUAV refers to was part of our research programme to find nutritional approaches to help manage inflammatory bowel disease (IBD). This is a disease that includes disorders such as Crohn's disease and ulcerative colitis, which are incurable and difficult to manage clinically. We used an animal model of this clinical condition to evaluate the anti-inflammatory properties of a new nutritional ingredient."