Global food scares are on the rise - meaning meat exporters need to get used to volatile earnings or risk following the likes of Pilgrim's Pride into distress, Fitch has warned.

A growing tally of livestock-related disease scares will continue to trigger "temporary sporadic bans" on global trade in meat products, despite efforts to keep sick animals out of the human food chain, the ratings agency said.

Even where bans are not imposed, consumers' meat-eating patterns are being "constantly negatively affected by the occurrence of animal illnesses".

The earnings damage to exporters from factors such as revenue slides and inventory build ups "will remain a concern", Fitch said.

The comments come days after the outbreak of H1N1, initially called swine flu, was declared a pandemic and as the Czech Republic tackles the discovery of cattle with BSE.

Best positioned firms

The report added that companies with global production bases, or diversified operations, were best placed to withstand such volatility.

Such businesses included Cargill, the global agribusiness giant, which is protected by the range of markets from which it took its $120bn in revenues last year.

US-based Tyson, while a meat specialist, gained some security from its strength across the three main meat markets – beef, chicken and pork – while Brazil's JBS had the advantage of operations spread through the Western world.

"This geographic diversification helps [avoid]... the tariffs or quotas applied regionally by some importing blocs or countries," Fitch said.

'Most vulnerable'

Single product operators such as Pilgrim's Pride, the US poultry producer which has filed for bankruptcy, were "most vulnerable to changing export policies," Fitch said.

Operating margins at National Beef, a US-based beef specialist, tumbled by more than 50% after the discovery of a single cow with BSE in America in 2003.