Once again, raw sprouts are sickening someone.
Eurosurveillance.com reports today that,
Between 10 and 15 October 2007, the national reference laboratory at the Norwegian Institute of Public Health (FHI) detected Salmonella Weltevreden in samples from four gastroenteritis patients. The patients were all living in the south-eastern part of Norway, and had no history of foreign travel during the month prior to onset of illness.
S. Weltevreden is a common cause of gastroenteritis in south-east Asia [1,2], but is a very rare serovar in Norway. Over the past 30 years, fewer than 10 cases were reported annually, only seven of which were domestically acquired.
In response to the detected cases, an outbreak investigation was initiated on 19 October in order to identify the source of the outbreak. It involved FHI, the Norwegian Food Safety Authority (NFSA), and the municipal medical officers.
An urgent enquiry was sent out through the European Centre for Disease Prevention and Control (ECDC) on 22 October. In response to the enquiry, Denmark reported a cluster of 18 cases of S. Weltevreden that was under investigation at the time. The onset of illness of the first cases had been in late July. In three cases, it was thought likely that the infection had been acquired abroad. On 26 October, Finland reported a cluster of seven cases that had occurred between 1 August and 1 October.
On 23 October, a salmonella isolate obtained from a major Danish alfalfa sprout producer was serotyped as Weltevreden. The Danish authorities issued an alert through the Rapid Alert System for Food and Feed (RASFF) on the same day. The isolate was later shown to have the same multiple locus variable number tandem repeat analysis (MLVA) and Pulsed Field Gel Electrophoresis (PFGE) profiles as the isolates from the case-patients from Denmark, Norway and Finland. S. Weltevreden has also been verified in the sprouts sold in Finland, but the PFGE result of this strain is pending.
The seeds for growing the alfalfa sprouts had been imported to Denmark in July and August 2007. The Danish producer had then exported part of the batch of seeds to a Norwegian alfalfa sprout producer on 19 September. The batch of seeds used in Denmark and Norway was traded, according to invoices, via retailers in Germany and the Netherlands to Denmark, and probably originated from Italy (further information is pending). No clear link has been found as yet to the seeds used in Finland, except that they came from the same Dutch supplier. A link may appear when the full traceability accounts from the Netherlands are provided through the RASFF system. The batch of alfalfa seeds had been imported to Finland in June. However, sprouts from this batch were not on the market in Finland before August.
The alfalfa sprouts were recalled and withdrawn in Denmark on 18 October, in Norway on 23 October, and in Finland on 28 October.