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DON’T believe people who tell you beefburgers are safe to eat once they’ve
gone brown. To cook beef safely, you should heat it to 70 °C—hot
enough to kill potentially lethal Escherichia coli O157. But Morse
Solomon and his colleagues at the US Department of Agriculture near Washington
DC, have shown that beef can brown at temperatures as low as 57 °C if it has
been frozen, exposed to air for a while or kept in an acidic environment. These
conditions alter myoglobin, the protein which gives raw meat its colour, making
the meat go brown at lower temperatures…