ACSA
The investigation into an outbreak involving around 200 cases of Salmonella enterica serotype Umbilo (S. Umbilo), published this month in Eurosurveillance, affecting several European countries between July and September 2024, identified rocket salad from an Italian company as the source of infection. Spinach from the same company was also contaminated by S. Umbilo.
Following alert from Austria, on 20 September 2024, through the European Alert Network (RASFF), the Italian food safety authorities took measures to stop the distribution of rocket salad and all products containing rocket salad from certain producers in a region of Italy, as well as ordering the withdrawal of these products from the market.
Salmonella Umbilo serotype is generally rare, with 20 to 32 cases annually reported by the European Centre for Disease Prevention and Control (ECDC) in the European Union/European Economic Area (including the United Kingdom until 2019) over the past 10 years.
With some 200 cases across at least nine European countries, the current outbreak is the first reported where S. umbilicus affects people.
Arugula salads have been the cause of numerous outbreaks since 2000: Salmonella Typhimurium in Sweden in 2022, a Salmonella Thompson outbreak in Norway in 2004, Salmonella Napoli cases in Sweden in 2008-2009, an Escherichia coli STEC outbreak in Finland in 2016, and a hepatitis A virus outbreak in Sweden in 2000-2001.
Foodborne outbreaks associated with fresh produce, including leafy green salads, are a challenging public health issue, because these foods are widely promoted as part of a healthy diet and are eaten uncooked. Contamination of fresh produce can occur at different stages of the food production chain, for example when animal manure is used as fertilizer, contaminated water is used for irrigation or for pre-washing of produce.
This outbreak serves as a reminder that salmonella can appear in fresh produce, including leafy green salads, intended for consumption without prior cooking.