Fresh fruit, vegetables and salad sprouts in Australia are responsible for an increase in food poisoning caused by the potentially deadly salmonella and E-coli bacteria.

There were 27 outbreaks of gastroenteritis between January 2001 and June 2005 across Australia due to fresh, uncooked produce including orange juice, cucumbers, lettuce and alfalfa spouts, resulting in almost 700 people becoming ill, with 51 hospitalised, a conference has been told.

At least half of the outbreaks occurred at restaurants and nearly one-fifth of gastro illnesses were linked to fast food or takeaway shops.

The Communicable Disease Control Conference was told this month that fresh produce in particular may cause outbreaks because it was often eaten raw.

Adrian Bradley from the NSW Food Authority said the widely held assumption that fresh produce didn't harbour pathogens such as salmonella, norovirus and Campylobacter was now known to be incorrect.

OzFoodNet, the Australian food-borne illness surveillance system, shows that three major salmonella outbreaks occurred in 2006. More than 120 people in Western Australia and Victoria fell ill in the first half of last year after eating alfalfa sprouts.

In October 2006, more than 120 cases of food poisoning caused by eating rockmelons occurred along the eastern seaboard. In November there was a small outbreak of salmonella linked to pawpaw.

Overseas evidence suggests contaminated water, fertiliser, contact with pests or animal faeces or insufficient cleaning of produce prior to sale could cause contamination.

A spokesman for the country's Department of Health and Ageing said centralised growing and distribution of fresh produce, as well as enhanced detection, might be a factor in the increase in outbreak numbers.

Food Standards Australia and New Zealand (FSANZ) plans to introduce primary production and processing standards for high-risk fresh produce such as sprouts.

The NSW Food Authority said people considered "vulnerable" such as young children, the elderly, diabetics, pregnant women and those with cancer or suppressed immune systems should never eat any type of sprout. It advises avoiding any bruised, damaged, mouldy or slimy produce and washing all produce with cool tap water immediately before eating.