The safest hamburger to eat is one that has been flipped several times, according to research from the Lawrence Livermore National Laboratory, California, published in The New York Times.

By flipping the beef pattie frequently, the burger will cook faster and reduce levels of amines, chemicals linked to cause breast and prostate cancer in animals.

The study showed that burgers flipped once took 8.9 minutes to cook and had 5.7 nanograms of amines per gram of beef, as opposed to burgers flipped every minute that took 7.1 minutes to cook and contained 0.5 nanograms. Juices inside the meat must surface to form the amine compounds but frequent flipping prevents the juices from reaching the point of reaction.

By Monica Dobie, correspondent