It is almost always instructive to read the detailed reports of investigations into food poisoning outbreaks, especially when the specific causes of the outbreak are clearly identified and properly explained. Often, the problem will have been traced to a systemic flaw or human error and the findings can be very helpful for other food manufacturers anxious to avoid a similar occurrence.
A case in point is the recent publication of a report by Dutch investigators relating to the Netherlands biggest ever Salmonella outbreak, which happened back in the autumn of 2012. At least 1,149 people were infected by a strain of Salmonella Thompson in the outbreak and four deaths were reported. The investigators established a link with consumption of smoked salmon processed at a single site and this was confirmed by epidemiological and microbiological evidence. The investigators’ report suggests that over the course of the outbreak, four to six million Dutch citizens could have been exposed to the contaminated salmon and the number of confirmed illnesses might be a considerable underestimate of the actual figure. The true number could have been as high as 23,000.
And the reason for the contamination? The investigators found that the manufacturer had been using reusable dishes that were cleaned and sanitised between production runs. Unfortunately, it turned out that the dishes were in fact porous and provided an ideal environment for bacteria, including Salmonella, to accumulate and be protected from cleaning and sanitising chemicals. Where the Salmonella came from in the first place remains a mystery, but the outcome was long-term continuous contamination of smoked salmon placed in the dishes during processing. No wonder the outbreak was such a large one.
There is a clear lesson here for manufacturers of ready-to-eat foods to ensure that all processing equipment, utensils and containers are suitable for food use and designed according to good hygiene principles so that they can be properly cleaned. That should be common sense, but when the consequences of an error are as serious as they were in this case, it reinforces just how vital it is to get it right. A simple mistake can mean that a lot of people get sick and can even result in fatalities, not to mention the probable demise of the business concerned. That is why it is important that this kind of report is published wherever possible. The more information about outbreaks and their causes that is publicly available, the more likely it is that a repeat can be avoided and the safety of the food supply can be improved.