Dec 12, 2011 (CIDRAP News) Though botulism outbreaks in Europe are often traced to home-canned food, three recent outbreaks were linked to commercially distributed food, raising important food safety issues, investigators reported last week.
The botulism outbreaks occurred in France, Finland, and Scotland and involved 11 cases, including a fatal one. Public health officials involved in leading the investigations reported their findings in Eurosurveillance.
Though authorities didn't find any direct links between the three outbreaks, they did find some similarities. Olive products were the vehicles in the French and Finnish outbreaks, and a prepackaged korma curry sauce was the source of the Scottish outbreak.
Botulinum toxin is a nerve poison produced by Clostridium botulinum. Botulism symptoms include double or blurred vision, droopy eyelids, slurred speech, difficulty swallowing, dry mouth, and muscle weakness. If not treated promptly, illness can progress to paralysis of the limbs, trunk, and breathing muscles.
Two clusters in France
The French outbreak attracted the attention of health officials when a hospital clinician reported five suspected botulism cases among eight people who had attended the same dinner party in the southeastern part of the country.
The patients, adults in their mid 50s through mid 80s, got sick 24 to 36 hours after the meal and were hospitalized the same or the following day. All experienced quadriplegia, required intubation, and received a trivalent antitoxin. As of late November, all were still hospitalized.
Another person who attended the same dinner party experienced mild botulism symptoms and was hospitalized for 3 days.
The outbreak prompted an alert to French hospitals and poison-control centers from the French health ministry.
Two days after the first outbreak was reported to authorities, a second cluster emerged, affecting three of six people who had attended a family dinner in northern France.
Those who got sick, all in their 20s, came down with symptoms a day after the dinner and were immediately hospitalized. Like the first cluster, these patients had rapidly developing quadriplegia and needed intubation and mechanical ventilation. Hospital says ranged from 34 to 58 days.
An investigation into the first cluster found that the five sick patients had all consumed a ground green olive paste (tapenade) that contained green olives, garlic, capers, and olive oil. The person with milder symptoms didn't eat the paste, but said he or she used a knife that had been used to serve it. Some had also eaten a dried tomato paste.
In the second cluster, all three sick patients had also eaten ground green olive paste and a dried tomato paste.
Testing of leftovers from both meals found type A botulinum toxin in the olive paste. The sample of the dried tomato paste from the home of the first family tested negative for the toxin, but the tomato paste associated with the second cluster tested positive.
The trace-back investigation found that both families had eaten ground green olive paste that was produced on May 20. The dried tomato paste was produced on two different dates, about 2 months apart.
The families had purchased the olive and tomato pastes at two grocery stores in neighboring districts of the Provence region in late summer. Made by a local artisanal producer, both types of paste were sold in small glass jars with screw-top lids.
Inspectors found incorrect sterilization processes at the facility that produced the two products. No quality-control processes were in place, and the producer had not told local health authorities that he or she was involved in food production.
A recall notice was issued the day after health authorities learned of the first cluster, and no more related botulism cases have been identified in any EU member state.
Olives in Finland
The Finnish outbreak surfaced in the middle of October when federal officials learned of a suspected botulism case in an elderly person who died 14 days after admission to a Helsinki hospital. Four days after the patient was hospitalized, a young adult from the same household reported similar but milder symptoms. Both had eaten olives stuffed with almonds from a previously unopened jar.
Tests on the olives, part of a 900-jar lot imported to Finland from Italy in 2010, were strongly positive for type B botulinum toxin. The products had been distributed to grocery stores and restaurants in part of Finland and had been exported to other countries in and outside of the European Union. No other cases have been reported.
During the investigation, authorities noted some of the olive jars from two batches were leaking and some of the contents spoiled. However, lab tests didn't reveal any evidence of botulinum toxin in those jars.
Three Scottish siblings
The third outbreak occurred in early November in Scotland when two sibling children were hospitalized on consecutive days with suspected botulinum poisoning. A third sibling was hospitalized for similar symptoms 6 days after the first child was admitted to the hospital.
The first two children's conditions stabilized after mechanical ventilation and treatment with trivalent botulinum antitoxin. The third child received the antitoxin and was released 6 days after admission.
Food histories revealed that korma mild curry cause had been served at a family meal 2 days before the first child was hospitalized. Two siblings had eaten the sauce, and the third sibling and the father had tasted it.
The commercially prepared sauce had been distributed in the United Kingdom and Ireland. Type A botulinum toxin was detected in residual sauce from a jar from the family's recycling bin, plus sauce-containing remnants from the meal.
Authorities recalled the implicated sauce batch. An investigation into the company's production and distribution systems is continuing, but so far it's not clear how the jar became contaminated. No other illnesses have been reported.
Differences and similarities
In an editorial in the same issue of Eurosurveillance, Dr John Cowden of Health Protection Scotland noted that the outbreaks had intriguing differences and similarities. Two were limited to single households, and two included olives as food vehicles. All products were marketed in jars with screw-top lids.
The Finnish and Scottish outbreaks were linked to commercial products. The French and Scottish outbreaks were cause by type A toxin, and the Finnish outbreak by type B.
Though problems that might explain contamination were found in the Finnish and French outbreaks, the korma sauce linked to the Scottish outbreak was produced in a state-of-the-art facility, and the intensive probe has still not found any culprits, Cowden wrote. He added that the number of cases was surprisingly low, given suspected production problems that would have affected entire batches of jars.
Cowden wrote that the outbreaks serve as reminders that even modern production methods can allow contamination. If producers can't completely eliminate the risk of contamination, secondary preventionmeaning the speedy identification, investigation, and control of outbreaksbecomes crucial.
In each of the outbreaks, systems, including the EU Rapid Alert System for Food and Feed, worked well, he said. In the European Union, clinical and investigation information about outbreaks is shared through the Epidemic Intelligence Information System and the Early Warning and Response System.
"They can serve as a good example for politicians and policymakers who need to be aware of the necessity for the continuing development of such vital health protection activities, even in the current climate of constrained resources," Cowden wrote.
Pingeon JM, Vanbockstael C, Popoff MR, et al. Two outbreaks of botulism associated with consumption of green olive paste, France, September 2011. Euro Surveill 2011 Dec 8;16(49) [Full text]
Jalava K, Selby K, Pihlajasaari A, et al. Two cases of foodborne botulism in Finland caused by conserved olives, October 2011. Euro Surveill 2011 Dec 8;16(49) [Full text]
Browning LM, Prempeh H, Little C. An outbreak of foodborne botulism in Scotland, United Kingdom, November 2011. Euro Surveill 2011 Dec 8:16(49) [Full text]
Cowden J. Foodborne Clostridium botulinum intoxication from mass produced foodstuffs in Europe. (Editorial) Euro Surveill 2011 Dec 8;16(49) [Full text]