A total of 35 confirmed Salmonella Agona infections among infants aged less than six months were found in different regions of France and for most, consumption of infant milk formula could be confirmed.
Sixteen cases were hospitalised and later discharged. The first was retrospectively identified in April 2017.
Discriminatory characteristic of outbreak strain
Institut Pasteur found the outbreak strain displays atypical biochemical characteristics and did not produce hydrogen sulphide and gas during 18 hours incubation on Kligler-Hajna media.
This characteristic appears discriminatory enough to identify probable outbreak cases, said the European Centre for Disease Prevention and Control (ECDC).
This trait was found in all cases in France and those from Spain and Greece.
Lactalis Nutrition Santé group recalled over 600 batches (more than 7,000 tonnes) of products manufactured at its site in Craon in France from mid-February last year.
The firm said two positive Salmonella tests, in August and November, were found in the environment and not in products.
Distribution was to 67 countries including 12 in the EU: Belgium, Bulgaria, Cyprus, Czech Republic, France, Greece, Ireland, Netherlands, Romania, Slovenia, Spain and the UK.
Biochemical tests and whole genome sequencing
Whole genome sequencing (WGS) analysis confirmed the Spanish case is associated with the outbreak in France and may provide further confirmation on the Greek case and possible infections from other countries.
ECDC is offering WGS services to countries which do not have the possibility to do timely analysis, with comparison of sequences by Institut Pasteur.
“Biochemical tests, and ultimately whole genome sequencing analysis, will confirm whether cases of Salmonella Agona in infants are linked to the outbreak,” said ECDC.
“A broad recall of infant products, an export ban and the suspension of market distribution, implemented since the beginning of December 2017, are likely to reduce the risk for new human infections.”
ECDC and the European Food Safety Authority (EFSA) will publish a joint assessment of the outbreak later this month.
French authorities ordered suspension of marketing and exports and the recall of several infant formula products made by Lactalis.
Five different brands of infant formula from the processing facility were implicated as the vehicle of infection. The Craon site was shut down on 8 December.
French authorities recommended heating the formula for two minutes at 70°C and let it cool down to 37°C before serving to infants.
Lactalis said contamination can be traced to an evaporation tower used to dry out milk at the factory.
“We wish to extend our sincerest apologies to the families affected. We are well aware of the seriousness of the situation and fully understand the anxiety and inconvenience that have been caused.
“Food safety for all our consumers and all our products is our highest priority, which is why we are taking such rapid and drastic measures in order to deal with this situation.”