- 09 April 2019
Dr. Rosalind Stanwell-Smith, Deputy Editor of Perspectives in Public Health gives her review of Food Poisoning - The Challenges and Controls which took place on the 20 May 2015.
Food poisoning must be one of the oldest problems known to human kind, yet we’re still seeking how to control it. It’s responsible for millions of cases and lost working days each year in the UK – and it is also under reported, with one recorded case for every 147 estimated illnesses, according to a recent study.
For a new look, this conference provided a great mix of topics, including clever technology to promote hand washing, combatting Escherichia coli, the kind of evidence needed for public health action and behind the scenes advice on court cases. The conference coincided with the widely reported news that 70% of poultry in England and Wales is still contaminated with the bacterium Campylobacter, the second largest cause of food poisoning. A third of us are likely to catch it, including vegetarians since vegetables, salads and soft cheeses have all been implicated in outbreaks.
As for E. coli, some faecal waste still ends up in British coastal waters, although Amanna Giles from the Environment Agency gave assurance on the steady progress to reduce this, including robust models to predict pollution and studies on E.coli survival in sand and with different levels of sunlight. Something to think about when you next take a dip or have a picnic by the sea, even at beaches meeting current standards: remember that there are other sources for E.coli than sewage.
We still call it food ‘poisoning’, a legacy of the days when notification was first established, but the main causes are infectious microorganisms, with norovirus leading the rest at 3 million cases a year. This virus is notoriously infectious, both via aerosol from vomit and transfer via hands. So it was depressing to learn from Professor Lisa Ackerley that 39% of caterers admitted that they wouldn’t wash their hands after going to the toilet, while 48% wouldn’t wash hands after handling raw meat.
As for office workers, 50% confessed (presumably in another anonymous survey) to not washing their hands after toilet visits, which may explain why around 3,000 organisms can be isolated from just one square inch of a computer keyboard.
Danish hygienist Lars Forsberg presented innovative approaches to encourage hand washing, such as sensors on taps and soap dispensers that emit a sound if not used after a loo visit – with this type of “intelligent washroom infrastructure” also providing reports on system use and status – no excuse for soap running out! In studies, the sensor-sounds intervention dramatically increased soap and water use for hand washing compliance, such as from 40% up to 80% in schools and from 65% to 98% in clinical settings.
The FSA has had success also with food hygiene ratings [FHRs] displayed on premises, which is one way of making the 600,000 or so UK food businesses read and apply the guidelines – and limit cross contamination with E.coli and other organisms.
It makes sense, for example, to insist that equipment such as slicers should be easily dismantled and cleaned, but the system depends on inspections as well as the ratings – and educating the consumer as to what constitutes a risky food.
Outbreaks usually prompt action in applying control measures, but interpreting the evidence needed for action goes beyond counting cases and laboratory positives. As Dr. John Cowden explained with witty quotes and apt examples, the evidence is at best circumstantial, even with superb epidemiology. It has to be collected after the event when there may be few or no traces left of the suspected cause. So both ‘internal’ and ‘external’ evidence must be sought, incorporating the circumstances, such as hygiene faults, as well as microbiology and the food histories given by patients and controls.
After only a few cases of Salmonella infection due to an unusual strain, a snack sausage product was withdrawn in 1989 – the first instance of removal of a food based on epidemiological evidence alone. Similarly a hazelnut yoghurt was withdrawn after five cases, when four were shown to have eaten it, again with a rare strain that made the cases stand out from routine salmonellosis reports.
John Barnes of the FSA highlighted a topical problem – the undercooked burger. The trend in burger restaurants is to offer the option of ‘rare’ burgers as if they were steaks - always go for “Cook it all the way through, please” if you want to keep the risk of E.coli O157 low. Meanwhile, preparing chicken means understanding that the outer packaging may also be contaminated and not to wash raw chicken: we were urged to join the ‘Chicken Challenge’ on the FSA website.
When food poisoning is considered by a court of law, it’s a little late to consider prevention, but solicitor Amandeep Dhillon outlined the key pitfalls. Hygiene logs hurriedly completed all at once are a bit of a giveaway and pre-action disclosure orders should be expected for all documents relating to management of food premises, including staff training and incident preparedness plans.
If a breach of hygiene has occurred, the next step is to prove that this breach caused the illness. Attempts to distract the investigators by claiming that victims ‘ate elsewhere’ or ‘over-indulged’ are unlikely to succeed. Denial of liability is frequent, in the hope that evidence will not show consumption at the venue in question: if the microbe strain is common, it is harder to prove, but with good epidemiology, the balance of probabilities is easier to judge.
A brilliant joint presentation of an outbreak linked to a pub lunch followed the legal theme and the day was rounded off with a lively question session and thought provoking ideas from food safety manager Jacqueline Bloomfield, on what ‘good’ looks like.
Training innovations tried out at John Lewis include getting staff to sketch their premises and map the work flows – great way of understanding clean versus dirty areas. It’s not just training: selection of the right people, understanding behaviour and motivating towards goals are all involved. And of course hand washing.