Between May and June this summer, the UK saw a spike of 288 confirmed cases of E. coli 0157 illness, scattered across the countries. Surprisingly, but thankfully, no fatalities have been reported. The outbreak even has its own Wikipedia page;
https://en.wikipedia.org/wiki/2024_United_Kingdom_Shigatoxigenic_E._coli_outbreak#:~:text=As%20of%2027%20June%202024,with%2067%20people%20requiring%20hospitalization.
The source appears to have been salad leaves contaminated by floodwater, which itself may contain farm animal faecal matter; this is a well-known chain of causation, especially in the big feed lots of the USA.
So, what do we need to learn from this?
In catering, note whether bagged leaves are labelled “readyto eat/use” or require washing. Keep refrigerated (not that this is a great control for E. coli, as its infectious
dose is so low it doesn’t necessarily need to multiply up to higher numbers). Follow
the instructions! Also, check out page 57 of the current SFBB manual (Safe Method; Ready-to-Eat Foods). This advice is particularly relevant to “soil-on”, fresh-from-the-field products that haven’t been processed or packaged or in any way.
In manufacturing, a HACCP plan for a sandwich manufacturer would, in my experience, normally include a “sanitising rinse” for salad leaves, due to the level or risk arising from the complexity of their supply chain, as well as scale of their operations and the number of consumers likely to be involved. The sanitising agent is normally a mild acid, probably
no stronger than vinegar and usually quite organic in nature (not normally a harmful manufactured chemical; we’re not bleaching the leaves!). I would, however, be interested to visit the processors involved to audit their HACCP plans, sanitising processes, monitoring and verification, the very steps that are designed to prevent contamination issues such as this from happening.