Following a steep increase in cases of food poisoning caused by Salmonella Enteritidis Phage Type 14b (PT14b), investigations carried out by the Health Protection Agency have shown an important cause to be eggs prepared by caterers.
The number of reported cases of S Enteritidis PT14b has risen sharply from less than 200 a year prior to 2001 to 698 in 2002 and 922 in 2003. This increase is a combination of some big outbreaks in 2002 and 2003 and also a general increase in sporadic cases, the agency says. During 2002 there were three large outbreaks affecting over 450 people in the UK, and in 2003 a national outbreak affected over 500 people.
Dr Sarah O'Brien, who is leading the investigation for the agency said: "We were concerned by the increase in the number of cases so we carried out a study which involved interviewing those who had been ill, and comparing foods they had consumed and places they had eaten in with people who had not been ill. The results showed us that the people who had been ill were more likely to have consumed eggs outside the home. These eggs were consumed in a wide variety of shops and catering premises.
"Our investigations in 2002 showed us that some outbreaks were caused by Spanish eggs. Using genetic fingerprinting, we have compared some of the human samples in 2003, with those taken from both humans and eggs in 2002 and they are all identical. This means the continued increase in infections caused by S. Enteritidis PT14b in 2003 might also have been be caused by eggs imported from Spain, but it is still too early for a definitive answer at this stage."
Dr O'Brien concluded: "Caterers need to remember that raw shell egg can be contaminated with Salmonella and follow Food Standards Agency advice that shell eggs should be cooked until the yolk is hard, and any products containing raw or lightly cooked eggs should be made using pasteurised eggs"
Back in October 2002, the UK Food Standards Agency, issued a warning which also identified Spanish eggs as being a potential carrier of Salmonella bacteria.
The fact that the study has pinpointed Spanish eggs as a problem area could do much to change patterns of sourcing within the UK food industry, and indeed throughout Europe. It is also likely to have an impact on Spanish food safety authorities as well as Spanish egg producers, who will be under pressure to react to the problem.