More tainted ingredients have been uncovered. And more food poisoning cases have come to light.

As of yesterday, there were 143 food poisoning victims, up from the earlier figure of 109, including 11 who were hospitalised.

One young patient is still in a ward. The Straits Times understands that the patient is a child who was discharged but later readmitted when her symptoms returned.

The investigations by the Agri-Food & Veterinary Authority and the Ministry of Health (MOH) revealed yesterday that another four workers from the PrimaDeli factory have been found to be carrying the bug. This brings the total to six affected workers at the Keppel Road factory.

A food handler at one of the 39 bakery franchise outlets has also tested positive for salmonella enteritidis.

Another ingredient has been found to be tainted by the diarrhoea-inducing bacteria.

Chocolate cream was the second contaminated ingredient found. Hazelnut paste was discovered on Wednesday to contain the bacteria.

Investigations are still under way to identify the source of the outbreak, said the AVA and the Health Ministry in a statement last night.

The authorities reiterated that people should throw away anything they have bought from PrimaDeli. They should get medical attention immediately if they show signs of food poisoning.

PrimaDeli's general manager Lewis Cheng said yesterday: 'We wish to reiterate that we are sorry and saddened by the recent incidents of food poisoning.'

The staff who tested positive for salmonella were also being treated, he added in a statement.

So far, about 50 people have called its hotline, set up for affected customers, at 6277-7171.

PrimaDeli's Keppel Road bakery and its 39 franchise outlets will remain closed for at least a week while the food sleuths do their work and for a thorough disinfecting.

The company said that it had worked with the AVA and the Health Ministry to put in place an action plan to work towards resuming operations.

Commenting on the new findings, Associate Professor Dale Fisher, a senior consultant from the National University Hospital's division of infectious diseases, said that, while more carriers may have been uncovered, they may not necessarily be the cause of the outbreak.

This will be made clear only after the exact strains of salmonella enteritidis carried by the workers are matched against those in the cakes and the victims, he explained.

What was most critical for food handlers, he stressed, was hygiene. Even if they had been carriers, they would not have spread the bacteria if they had taken the proper precautions.

Similarly, people should observe good hygiene. They should wash their hands with soap and water frequently, especially after toilet visits, changing diapers and before eating or preparing food.

At a food safety event yesterday, Minister of State for Trade and Industry Lee Yi Shyan stressed that the food produced here is only as safe as the workers who handle and make it.

'I think for the food to reach the consumer safely, you really need the system and the people within the system to work very well,' he said.

'It is obvious that any person who is sick or who is suspected to be not feeling well should not go on to the preparation table,' he added.

Those with questions can call the MOH at 1800-225-4122 or the AVA at 1800-226-2250.

diothman@sph.com.sg

huichieh@sph.com.sg