Swedish investigation finds risk of contaminated spices in other countries

An outbreak investigation into spices sickened 178 people in Sweden has revealed a risk of contaminated products on the market in other countries.

The first case was reported on 24 December 2014 and the latest count includes data up to 31 July. More than half of the patients (113) fell ill after eating at a restaurant linked to using Iwi spice mix sold by the company Dimpex .

Another firm, Sevan, issued a withdrawal after Salmonella found in some of its already opened products but it is not part of the restaurant outbreak.

 Each year, around two to five cases with Salmonella Enteritidis phage type (PT) 13a are reported.

In 2014, four of the domestic S. Enteritidis cases were PT 13a, according to the research in Eurosurveillance. Minor increase could go unnoticed Sweden launched an ‘urgent inquiry’ in the Epidemic Intelligence Information System (EPIS), on 2 April. No other country has reported an increase of this specific subtype of S. Enteritidis. However, many European Union Member States only subtype S. Enteritidis in outbreak situations or cluster investigations and phage typing or MLVA is not frequent in all EU countries so a minor increase could go unnoticed.

A Rapid Alert System for Food and Feed (RASFF) alert by Austria on 26 June reported Salmonella spp. in a spice mix/seasoning from a manufacturer in Croatia, with a similar content of dried vegetables as one of the brands implicated in the Swedish outbreak. The specific batch from which Salmonella spp. was not available in Sweden. The serotype was S. Oranienburg (not S. Enteritidis PT 13a), according to the Austrian Salmonella Reference Centre. In countries with a high number of reported cases of S. Enteritidis infection, however, a small increase in number of cases with the outbreak strain could go undetected. 

The detection of Salmonella spp. in two different brands of spice mixes sold in Sweden and the RASFF alert from Austria during the outbreak period, however, indicates that there could be a common ingredient in these mixes that are contaminated with Salmonella spp.

Swedish investigation Initial investigations suggested the vehicle of infection was most likely a food item with a long shelf life given the first case was in December. By the end of May, cases increased to 48 and were from over 14 counties. At the beginning of June, Kalmar county reported a case who had fallen ill after eating at a restaurant, cases continued to be reported and at the end of the following week six people were ill. As they all shared the strain, S. Enteritidis PT 13a. In total, 108 cases were connected to the restaurant, including staff members. Many had severe symptoms, including bacteremia, and were hospitalized but exact numbers are not yet known.

Culture analysis require dilution steps and number of replicates were often necessary to detect and isolate Salmonella spp., indicating very low concentration of the pathogen in spices.

Source: Eurosurveillance, Volume 20, Issue 30, 30 July 2015 “Outbreak of Salmonella Enteritidis phage type 13A infection in Sweden linked to imported dried­ vegetable spice mixes,