The world has become more vulnerable to outbreaks of disease caused by contaminated food because of growing global trade, the World Health Organization (WHO) said Thursday. Investigating these outbreaks has also become more difficult because food can contain ingredients from around the world and is transported through a complex global supply chain, top WHO officials said. \"Outbreaks of food-borne disease have become an especially large menace in a world bound together by huge volumes of international trade and travel,\" said WHO director-general Margaret Chan at a conference in Singapore on improving preparedness against global health threats. \"They are large in their potential in terms of geographical spread often involving multiple countries.\" One challenge faced by governments worldwide is how to \"reduce the health and economic consequences of food-borne diseases\", Chan said. She cited an outbreak this year of a new killer E.coli strain, which infected almost 4,000 people and left 51 dead across Europe and caused massive losses to vegetable farmers. European farm products such as tomatoes, lettuces, courgettes and sweet peppers were withdrawn from the market between late May and the end of June as a result of the disease, while Russia briefly banned EU vegetable imports. The European Union had blamed the outbreak on fenugreek seeds imported from Egypt, although Cairo denied any responsibility. \"Problems nowadays can arise from any link or kink in a convoluted food chain,\" Chan said. WHO assistant director-general Keiji Fukuda said food-borne outbreaks have occurred in the past. \"But what is different now is that food goes all around the world, so if you have something which gets contaminated or infected in one country it can be in 50 countries or 100 countries or 200 countries,\" Fukuda told reporters on the sidelines of the Singapore conference. \"So the scope of these outbreaks could be much larger and more complex and affect many more people.\" Fukuda said however that while the risks have become higher, the WHO is also working to make sure that authorities are able to deal with the problem. \"It\'s a kind of a race,\" he said.