Dr Hector Perera          London

If anyone watched British TV cooking programmes, you would notice the contestants always produce far too much cooking aroma while cooking. When they cook, they have to stay there that means they invariably inhale those unhealthy fumes. The so called judges appear to be not taking any notice of how the contestants cook as far as the final products are palatable to them. Who would agree that kind of cooking and judgements are right and let the public watch that kind of competitions. Sometimes TV is a media for educating the public but these kinds of cooking certainly would not help the public to cook in the correct manner.

Research findings about cooking aroma

Exposure to cooking fumes is abundant both in domestic homes and in professional cooks and entails a possible risk of deleterious health effects. When food is cooked at temperatures up to 300°C, carbohydrates, proteins, and fat are reduced to toxic products, such as aldehydes and alkanoic acids which can cause irritation of the airway mucosa. Cooking fumes also contains carcinogenic and mutagenic compounds, such as polycyclic aromatic hydrocarbons and heterocyclic compounds. Exposure to cooking fumes has also been associated in several studies with an increased risk of respiratory cancer. Recently, the International Agency for Research on Cancer has classified emissions from high temperature frying as probably carcinogenic to humans.

Frying at high temperatures also produces aerosols of fat with small aerodynamic diameters of 20–500 nm which disperse in the air of the kitchen and nearby facilities. Such aerosols, containing fatty acids, irritate the airway mucosa, and can cause pneumonia. It has also been shown that the inhalation of aerosols of oil mist from other kinds of oils can cause small airway obstruction. Chinese investigations have shown that exposure to cooking fumes at work can be associated with rhinitis, respiratory disorders, and impaired pulmonary function. Have you noticed some people start to scratch the eyes or drop tears due to sprays from onions and green chillies that is also a sign of rhinitis irritation? Irritation of the airways can be produced by a number of dusts, gases, vapours and fumes. These gases can also irritate the eyes. The part of the respiratory tract affected by a gas or fume is determined by its solubility. Highly soluble gases, such as ammonia, have immediate effects on the upper respiratory tract (and eyes). Usually, if someone is exposed to an irritant they’ll move away from the source, limiting any damage. In two Norwegian studies, it has been shown that cooks and kitchen workers had an increased occurrence of respiratory distress associated with work and increased mortality from airway disease. Few other studies have addressed the biological effects of exposure to cooking fumes in western domestic and professional kitchens. The so called judges in cooking programmes must be aware of these facts and advice the contestants how to reduce those things.

Spirometry is the most common, and also a quite sensitive pulmonary function test. It has been used for a long time in many investigations, for detecting chronic work-related impaired lung function in general, but it has also been possible to study short term cross-shift changes in different settings. The traditional spirometric time-volume curve measures the bowl function of the lungs, while flow-volume curves and other measures also give indications of the function of the smaller and more peripheral airways.

No ventilation due to loss of heat

The aim of this study was to see if short term exposure to moderate levels of cooking fumes in an indoor environment causes changes in pulmonary function. In cold weather countries, they hardly ventilate the sitting room and bedrooms due to loss of heat. When cooking aroma got stuck inside these places, the occupants have no choice other than to inhale those gases. Fortunately back in Sri Lanka, the rooms and sitting rooms have wide opened windows so that any unwanted gases just easily escape. Now the things are changed a bit due to air conditioners but not in all places.

Smell in restaurants

Commercial cooking produces fumes that pollute air and may harm our health. Sometimes one get this cooking aroma smell in restaurants, even when you walk past those places then how about the situation inside? Some restaurants have already changed the way they cook as a result of the findings. To protect yourself at home, you might want to bake and steam instead of broiling or deep-frying.

Cooking smoke contains particles known to both pollute air and cause cancer, scientists reported this week at a meeting of the American Chemical Society in San Francisco. The study zeroed in on the dirtiest emitters: broiled hamburgers and wok-fried chicken. Some major restaurant chains have already changed the way they cook as a result of the research, and parts of California have enacted new emissions standards for commercial kitchens. The findings should also help experts to develop better filtering technologies and consumers to make healthier, more environmentally sound choices in the kitchen.

Cooking is a very old habit

People have been cooking food for more than 100,000 years, said Tim Farrell, a chemical engineer and independent consultant in St. Paul, Minn. Ventilating windows and chimneys have likewise been around since the Dark Ages. Yet, it wasn’t until the mid-1990s that scientists started probing the contents of cooking smoke and how that smoke might contribute to air pollution.

The first comprehensive study looked at a handful of appliances commonly used in restaurants, hospitals, schools and other commercial settings. That study, conducted about a decade ago, found that the most and the dirtiest emissions came from broiling hamburgers under high heat. Other methods lagged far behind, including cooking French fries in a deep fryer or baking pizza in an oven.

In the new study, Kuehn and colleagues used state-of-the-art analytical equipment to examine in even more detail the vapours and particles that come out of a larger variety of cooking methods and foods. They found that the dirtiest smoke by far came from diced chicken cooked with peanut oil in a wok. Broiled hamburgers came next. With chemical analyses, the researchers identified compounds called polycyclic aromatic hydrocarbons (PAHs) in both particle and vapour released in cooking plumes. PAHs are known carcinogens.

In China more cooking done by women

So far, there are no proven health risks to breathing in cooking fumes, but it’s a hard link to make. As with cigarette smoke, though, the worry is that tiny particles in cooking smoke could get lodged deep into our lungs, where they might cause cancer or other problems.

One study conducted more than a decade ago found that cooking was by far the largest contributor to air pollution inside homes, Kuehn said. Another study in China, also conducted more than 10 years ago, found the highest rates of lung cancer in women, even though men smoked the most tobacco. Women do more of the cooking there, and the researchers speculated that their exposure to food fumes explained the trend. In Chinese cooking they cook in many different ways such as stir fry, oil velveting, blanching, dry roasting, steaming, poaching, braising, deep frying, hot pot, pan fry and steam combo and also by roasting.

Based on the new research, home cooks can make healthier choices in their own kitchens, Kuehn said. Because greasy foods cooked over extra-high heat produce the dirtiest emissions, stick with low-fat foods. Steam or bake food instead of broiling or frying. If you want to grill, do it outside, and make sure the hood in your kitchen forces air outside instead of recirculating it indoors. As a hungry consumer, Farrell added, you might want to avoid restaurants with particularly strong food smells, as odour indicates the presence of emissions. If you see grease dripping out of outdoor exhaust fans, that’s a bad sign, too. The good news is that advances in ventilation are coming. Your comments are welcomed perera6@hotmail.co.uk