Today, as is so often the case, I looked at a customer making an allegation of food poisoning, and they were convinced that the last thing they ate caused them to be ill. But this is often not the case at all.
For example, Campylobacter, the bacteria that causes more gastro-intestinal illness than any other in this country, has an incubation period of 1-5 days, and even as long as 11 days. This means that something you ate many days ago brews up in your intestines until it reaches a critical mass, and then you get the symptoms of diarrhoea – and wow what a nasty bug this one is.
In the past, patients have had their appendix removed because the intense pain convinced doctors that they had appendicitis. The diarrhoea can go on for days.
When we are trying to find out the cause of illness, if we know what the organism was that made someone ill, then we can make better investigations into the cause of illness as we can trace back to what was eaten within the incubation period.
The other red herring is norovirus, which may not have been carried by food at all. This virus is infectious in very low doses, and can be picked up from hand-contact sites, where these have been infected by someone who may be recovering from the illness. Protecting yourself from norovirus is simple – make sure you wash your hands before eating. Imagine if you eat a bag of crisps when travelling on the tube – think where your fingers may have touched just before, and think again about whether you may want to wash your hands – especially when you lick your fingers (UGH).