Flour and widely used baking additives such as the alpha-amylase enzyme were blamed for causing asthma-related symptoms, including chest tightness and wheezing, in 15 per cent of the bakery workers surveyed. A quarter of the workers said that their eyes and noses became irritated whilst at work, indicating a high sensitivity to the ingredients which can increase the chances of developing asthma.
Researchers monitored 239 bakery employees, including bakers, managers and assistants, representing 20 in-store bakeries belonging to one of the UK's major supermarket chains. Only stores which baked products from scratch were surveyed as those merely baking off par-baked goods do not come into contact with the raw ingredients.
Workers were required to record any symptoms they felt during work and any changes outside of work. They were also given skin prick tests to check for baking-related allergies; if someone has an allergic reaction to something then their blood will usually contain corresponding antibodies.
Dr Paul Cullinan, one of the study's researchers from Imperial College London, said that "while bakers' asthma is unlikely to prove life threatening it can have a significant impact on quality of life, leading to poorer health and forcing most to change jobs".
One of Cullinan's fellow researchers and colleagues, Dr Andrew Brant, agreed, adding that "once you have developed work-related asthma it only takes a tiny amount [of whatever caused it] to set you off again".
Yet Brant argued that important preventative measures could still be taken. He said there should be greater access to health services for workers and managers to increase awareness, and supermarkets must maintain good hygiene behind the scenes. "Another possible solution could be if supermarkets bought more of their additives as semi-solids instead of powder, but that would not solve the flour problem," he said.
The research team is still working with the supermarket involved, which has more than 300 UK stores, to examine the scale of the problem further and raise the profile of occupational asthma.
The issue has already received some attention across the bakery industry, although a study commissioned last year by the Advisory Committee on Toxic Substances, revealed a low level of compliance with the Control of Substances Hazardous to Health (COSHH) Regulations, and that only 27 per cent of bakeries were aware of exposure limits on flour dust.
"While bakers' asthma is not a new phenomenon, this is the first time a study has been conducted in supermarket bakeries. This is a new occupational health issue and is especially important given the high and increasing proportion of baking that now takes place in supermarkets," said Brant.
Many of the major supermarkets, including Sainsbury's, Morrisons and Tesco have complete on-site baking facilities as well as facilities for par-baked goods. The amount of baking from scratch has increased in the last 15 years as retailers have moved into larger out-of-town stores capable of housing more equipment. In-store bakeries account for almost 20 per cent of the UK bread market.