More than 20 new salmonella infections have been identified in the last week amid three major outbreaks linked to imported eggs, health officials have said. The UK Health Security Agency (UKHSA) has today confirmed a total of 549 cases of the life-threatening bacterial infection – a jump from 528 last Thursday.Two people have died in the outbreak, believed to have been caused by imported eggs.Cases have been linked to eating out at 'small cafés, restaurants and takeaway businesses', according to the UKHSA. Officials say there is no evidence that eggs produced in the UK pose any threat.Food safety chiefs have urged Britons to avoid 'raw or lightly cooked egg' products such as mousses, mayonnaise or hollandaise sauce. Vulnerable groups – including over-65s, pregnant women and under-fives – are also advised to avoid runny eggs when eating out.This is because it may be unclear whether cafés, restaurants and takeaways are using eggs bearing the British Lion mark or those produced under the Laid in Britain scheme, which are deemed safe. More than 20 new cases of salmonella have been identified in the last week amid three major outbreaks linked to imported eggs, health officials have saidThe total number of cases in the outbreak is spread across three separate infection 'clusters'.Some 322 infections have been recorded in the one, up from 305 this time last week, and one person has died.Another death has been recorded in a cluster with 41 cases, while the remaining 186 infections - up from 182 last week - have been linked to a third spread.As public health officials rush to identify the source of the eggs causing the spread in Britain, cases of salmonella have also been reported across Europe.This includes in Austria, Belgium, Denmark, France, Germany and the Netherlands.Experts told the Daily Mail last week that the true rate of infections is likely significantly higher in the UK than officially reported.Paul Wigley, a professor in animal microbial ecosystems at University of Bristol, said: 'It could be 1,500 to 2,000 or so. I wouldn't be surprised if it's up around the 2,000 mark.'In fact, I wouldn't be shocked if it's much higher than that. But around 1,500 to 2,000 cases is what I would be expecting.' There are around 10,000 lab-confirmed cases of salmonella in the UK every year. However, Food Standards Agency (FSA) chiefs believe the true number may be around 32,000.Professor Wigley said this is because hundreds of patients may have milder forms of the disease without severe symptoms such as prolonged diarrhoea.They are unlikely to seek medical help, so may not be analysed and later confirmed as an official case.While salmonella – caused by bacteria entering the body – can be deadly, some people with stronger immune systems can shake it off within around a week.'Most people are just going to say, I'm not that ill, I'm not well, but I'll ride it out,' Prof Wigley explained.