Food and medical authorities in the USA have stepped up safeguards against mad cow disease amid panic that theirs could be the next country to be hit by BSE.
The US Food and Drug Administration (FDA) is under pressure to tighten up a federal ban on feeding animal meal to cows and sheep. This week the National Cattlemen's Beef Association (NCBA) met FDA officials to discuss the ban's effectiveness.
The move followed news that a Texas feed mill may have inadvertently mixed meat and bone meal derived from US cattle into cattle feed.
The FDA has restricted blood donations from people who have lived in western Europe, and people entering the USA from Europe face tougher screening from customs officials.
So far there have been no cases of BSE in the USA and the NCBA says beef consumption and demand have increased over the past two years.
But the scare has taken its toll on US-based restaurant chains. Sales at McDonald's European restaurants fell 10% in the three months to 31 December amid BSE fears on the Continent.
Overall sales for McDonald's worldwide rose by 7% during the year to more than $40b (£27b).
McDonald's, along with Wendy's International and the Outback Steakhouse chain, all saw their shares fall last week.
by Gillian Drummond