Of the 295 staff surveyed by researchers at the University of Dusseldorf, 35 per cent thought they could treat a customer having an allergic reaction by serving them cold water to "dilute the allergen", while one in five believed removing an allergen from a finished meal could be all that was necessary to provide a safe meal for a customer with an allergy.

Over 41 per cent said they believed some customers fabricated allergies.

In Australia, where allergy rates are among the highest in the world, the ignorance might not be as pronounced, but diners with serious dietary requirements can still struggle.

Jasmine Wels, a nurse from Brighton in Adelaide's south, had an anaphylaxis reaction last month after ordering Indian takeaway online.

After she and her husband repeatedly alerted the restaurant to her severe cashew nut allergy - leaving a note on the online form as well as checking when the order was collected - Wels, 38, says a call to the restaurant after her reaction began highlighted the lack of knowledge some people can have about food allergies.

"They said there were cashews in the samosa, 'so don't eat the samosa'," she recalls.

With three small children, Wels says the stress of using her epipen, calling an ambulance, and then being hospitalised takes its toll not just physically, but emotionally.

"The psychological, 'near death' stuff ... it's quite scary. I think my little three-year-old was quite traumatised, too, watching the whole thing."

Even when a menu claims to cater to people with food intolerances, there can be problems. A 2018 study of food sold and served as "gluten-free" by businesses in Melbourne revealed nine per cent contained levels of gluten that could be harmful to a person with coeliac disease.

Julia Jensen, 25, experienced this first-hand when on a date in Sydney's Darling Harbour.

The Sutherland Shire accountant, who has coeliac disease, ordered a meal marked gluten-free from a restaurant menu, only for her symptoms - cramping, vomiting and diarrhoea - to kick in after she had left an hour later, prompting a mad rush into another restaurant's bathroom.

"Any time eating out, it's like playing Russian Roulette with your health," she says.

Coeliac disease is an autoimmune condition, and Jensen says she usually experiences the effects of a reaction for a fortnight afterwards.

"A lot of people think you will just be sick for that night ... but it triggers your immune system to attack itself. For the next two weeks you have brain fog, you're so tired."

Maria Said, CEO of Allergy & Anaphylaxis Australia and co-chair of the National Allergy Strategy, says, while there is "a lot of fear" around cross-contamination - such as through the use of a deep fryer to cook multiple meals - reactions like Wels', where the allergen is "absent-mindedly" put in a diner's food are more common.

"I don't think people at risk of anaphylaxis should expect a guarantee that their food is safe, because there is always risk, but they should have the confidence that they have been understood and that manageable strategies are in place in the case of a reaction."

The consequences of ignoring a customer's food allergy can be disastrous.

Last year, the owner and manager of a UK restaurant were found guilty of manslaughter following the death of a 15-year-old girl who ate a takeaway meal their staff had prepared which, it was later revealed, contained peanut protein. Her order form had indicated she was allergic to prawns and nuts.

There have been recent local efforts to regulate and educate food outlets in relation to food allergies and intolerances.

Victorians who suffer an anaphylaxis reaction after eating at a food outlet can report their reaction to the state government and Coeliac Australia has begun a process of accrediting food outlets which actually provide "gluten-free" food. (So far, two have successfully applied, both in NSW: Beach Buns burger restaurant in Sandringham and Sue's Food Van on the Central Coast.)

In 2017, the Australasian Society of Clinical Immunology and Allergy (ASCIA) and Allergy & Anaphylaxis Australia launched a free online education course for food service workers.

Over 9500 food service staff have registered as taking part in the training, which Said says was developed in response to a food safety education focusing on bacteria and hygiene, rather than customer allergies.

"For someone with food allergy, a little bit of listeria or salmonella is probably safer than a little bit of peanut or milk," she says, adding she is "pleased" with the uptake although, in an industry with such high staff turnover, it is a case of "the word slowly getting out there".

"We do have people in food service who take it very seriously, but unfortunately we have others who really just don't get it."