Dr Hector Perera     London

The aroma of seared meat as your pan-fried steak is prepared may set your taste buds tingling but it may also give the chef respiratory related problems, especially if they are using a gas cooker. Cooking fumes produced during high-temperature frying are already known to cause some respiratory and pulmonary related problems. In China, high lung cancer rates among chefs have been linked to the practice of tossing food in a wok, often in a confined space, which increases the concentration of hot oil in the breathing zone of the cook.

The International Agency for Research on Cancer has also classified cooking fumes as “probably carcinogenic”. Now researchers from the Norwegian University of Science and Technology in Trondheim have compared gas and electric cooking methods, and found that gas produces higher levels of the cancer-causing fumes.

Keep off from moth balls

The results showed more naphthalene a banned substance contained in traditional mothballs and mutagenic aldehydes were produced when cooking with gas. Very often moth balls are used in wardrobes to keep off small creatures that destroy clothes. They are also commonly used in toilets to keep off the smells. Once the doors and windows are closed in the night, these chemical smells circulate in the air within the house including in your bedroom that comes from the wardrobe then also from the toilets because they have no way out.

They measured the fumes produced when frying 17 pieces of steak for 15 minutes each in conditions typical of Western restaurants, using margarine or two different brands of soya oil. The results showed more naphthalene, a banned substance contained in traditional mothballs and mutagenic aldehydes were produced when cooking with gas. Higher levels of ultrafine particles, which penetrate deeper into the lung, were also produced on the gas hob than on the electric one.

Exposure to cooking fumes are unhealthy

The authors, whose study is published in the journal Occupational and Environmental Medicine, point out that the levels of the chemicals and particulates found in their study were below accepted occupational safety thresholds. But they add that cooking fumes contain other harmful components for which there is no safety threshold, as yet, and which appear to be higher with gas cooking. “Exposure to cooking fumes should be reduced as much as possible,” they say.

Previous research has found that cancer levels are higher among chefs who did not have fume extractors in their kitchens than among those who did.

Cooking for long time on daily basis

Although smoking is the main cause of lung cancer in most countries, in Taiwan only 10 per cent of women with lung cancer smoke. By comparison, 86 per cent of Taiwanese men with lung cancer smoke. Researchers suggest that it is exposure to cooking fumes that accounts for the high rates of lung cancer in women, despite their low smoking rates. A study by researchers from the Institute of Medicine at Kaohsiung University in Taiwan published in the American Journal of Epidemiology in 2000 found that the longer women spent cooking food the higher the risk of lung cancer. Those who cooked on a daily basis had the highest risk. Women who waited until the oil was very hot before cooking the food increased their risk compared with those who cooked at a lower temperature.

Cooking oil heated above boiling point

‘Cooking fumes’ or ‘cooking oil fumes’ is the term commonly used to describe the visible emissions generated during cooking by frying with oil. However, these emissions are not technically ‘fumes’. In occupational and environmental hygiene, ‘fumes’ are defined as submicron-sized solid particles (particulate matter) created by the cooling of hot vapour. During cooking by oil, such vapour is formed when the cooking oil is heated above its boiling point. In addition to this ultrafine particulate matter, cooking, especially frying and grilling, generates aerosol oil droplets, combustion products, organic gaseous pollutants, and steam from the water contents of the food being cooked.

Some British TV Chefs

I am sure most of you have witnessed how some British TV chefs behave in cooking. It is better you witness their work and see what they do in the TV for the public viewing, is it acceptable? Some of them running in the kitchen area and add this and that to something they are preparing on full fire then toss it up in the air a few times then say, cooked”. When the piece of beef which they tossed up and down is cut to serve, it appears raw red. Now who would say it’s cooked? Quite often they set fire to the volatile ingredients thinking to get the attention of the viewers. They think higher the fire, more viewers. I am sure they try and impress the viewers in the wrong way. One other thing is the presenter lady or the gentleman has to stand very near to the chef who virtually dance around with that work otherwise the presenters would not catch in the TV. I feel sorry for the presenters who have to take part in the show even when the chef is behaving unacceptably.

The other forms of cooking such as boiling with water based media does not release particles as much as in frying with oil. Fortunately in domestic kitchens a limited number of frying takes place unlike in professional frying places such as in takeaway places. Even that little fumes cannot be let out without a proper ventilation due to the type of ventilation found in some kitchens.

A fume cupboard surrounding the cooker

When I visited some apartments in Colombo and the surrounding area, I found they do not have facility for adequate ventilation due to safety reasons. In most of those apartments there were children so for their safety reasons, the ventilation outlet is not made very large. I know it is for safety reason but in that case there should be a mechanical extractor but there was none. I must say except in high rise buildings, there was no problem of natural ventilation in other types of houses. Let me repeat what I suggested earlier, a fume cupboard must be installed around the cooker with a vent pipe connected to the outside. The front glass sliding doors can be moved as required and this controls any cooking fumes escaping into the kitchen atmosphere from where it spreads all over the house. Your comments are welcomed perera6@hotmail.co.uk