The Japanese breeding bull Kamitakafuku and his clones, which produced meat that met industry standards.© David Bauman, University of Connecticut

The composition of milk and meat from cloned cattle is no different from those of the same products obtained from naturally reared animals, says a team of US and Japanese researchers.

In one of the most comprehensive comparisons carried out to date, Xiangzhong Yang of the University of Connecticut in Storrs and his colleagues analysed more than 100 characteristics of the products. But the researchers' data is unlikely to defuse the debate over whether humans should actually eat these foods.

"All the parameters examined for the clones in this study were within the normal range of beef and dairy products approved for human consumption," says Yang. "We found no significant differences between the clones and their controls." The researchers' findings appear in Proceedings of the National Academy of Sciences¹.

Yang's team studied milk samples from four clones of a Holstein dairy cow for routinely measured parameters such as protein, fat, and lactose content. They found no significant difference between these parameters in milk from the cloned cows and from their matched controls. What's more, meat from two clones of the famous Japanese breeding bull Kamitakafuku fell within industry standards for parameters such as marbling and fatty-acid composition.

Although the beef from cloned bulls differed from that from non-cloned animals in certain parameters, including marbling and fatty acid composition, this is expected, the researchers say, because they were cloned from a superior bull with unusually high-quality characteristics. Overall, more than 90% of the parameters studied were the same as for non-cloned bulls, they add.

Although a 2003 risk assessment by the US National Academy of Sciences reported that the products from cloned animals and their offspring pose no additional threat to the food supply, the US Food and Drug Administration has yet to rule on whether to allow their sale.

The latest study may help to put consumers' minds at rest on the issue, hopes Michael Roberts, an animal biochemist at the University of Missouri-Columbia. "My hope is that this paper will dispel any lingering concerns that products from cloned but otherwise genetically unmodified animals are substantially different from standard milk and meat," he says.

There is little indication that that is actually the case. In a survey conducted last year by the Washington, DC-based International Food Information Council, 62% of American consumers said that would be "very unlikely" or "somewhat unlikely" to buy products from cloned animals.

"The public tends to equate safety with wholesomeness and purity," says Carol Tucker Foreman, director of the Food Policy Institute of the Consumer Federation of America in Washington, DC. She believes that most consumers would react with disgust to the prospect of eating food from cloned animals.

Yang concedes that his study involved relatively few animals, but says that the experiments should provide a basis for more extensive studies of cloned livestock animals. Similar findings using a wider range of clones could give more impetus to those who believe that the food products should be marketed. 

University of Connecticut

• References

  1. Tian X. C., et al. Proc. Natl Acad. Sci. USA, 102. 6940 - 6946 (2005).