Salmonella strain in Malaysian outbreak identified

The Salmonella strain behind a foodborne outbreak in Malaysia that has killed two people has been identified by authorities.

The Malaysian Ministry of Health (KKM) said the food poisoning was caused by Salmonella Weltevreden.

The total number of cases is 83 with 34 infections in Perak, 25 in Kedah and 24 in Selangor. No new cases have been detected since Oct. 9.

KKM said the suspected source is consumption of laksa, a type of noodle soup, purchased from premises in Kupang, a town in Kedah in the Baling district. It advised that food should be eaten no more than four hours after preparation, stored appropriately and heated to a sufficient temperature to prevent food poisoning.

Results came from the Sungai Buloh National Public Health Laboratory and Penang Food Quality Safety Laboratory. Ten food samples were sent to the lab for testing including laksa noodles and mixed ingredient salads for laksa.

Salmonella Weltevreden was detected in clinical samples from patients and a sample of the laksa. Using Pulse Field Gel Electrophoresis (PFGE) the bacteria was found in the laksa purchased on Oct. 4 from the stall. The laksa noodle was made at a processing site also run by the food stall owner.

Risk factors that contributed to the incidence of food poisoning could be the process of preparation and storage of unclean noodles and the temperature during processing not being sufficient to kill bacteria.

The stall selling the contaminated laksa has been closed since Oct. 8. KKM said the stall owner has been notified that they can reopen when judged to be compliant with food and hygiene laws. Training and education on prevention and control of diseases, as well as safe food handling, was provided.

The agency added it will intensify monitoring and enforcement activities to ensure food businesses are following regulations in the country with possible legal action against the owner or operator of a food firm that does not conform to the rules.

As no new cases have been detected in almost two weeks and the stall was closed, the outbreak looks to have ended. Symptoms of Salmonella usually appear 12 to 72 hours after infection and include fever, abdominal pain, diarrhea, nausea and sometimes vomiting. In otherwise healthy adults, the illness usually lasts four to seven days.

Salmonella Weltevreden was responsible for almost 900 culture-confirmed infections reported to the Laboratory-based Enteric Disease Surveillance (LEDS) system from 2006-2016, according to the Centers for Disease Control and Prevention in the United States.

The pathogen also entered the top 20 list for confirmed cases of human salmonellosis in the EU/EEA, 2014-2016 by serovar. A total of 224 cases were reported by 14 member states in 2016, according to the European Food Safety Authority and European Centre for Disease Prevention and Control.

(To sign up for a free subscription to Food Safety News, click here.)