VEGA News Item

Gas or Electricity – Which is the better to cook with? - 19/02/2010

There are Common Risks of Overheating. Beware!

1.  Electric hobs release fewer carcinogenic fumes when frying meat, according to a report from the journal Occupational and Environmental Medicine from the International Agency for Research on Cancer, describing new results from research done at the University of Science and Technology in Trondheim, Norway.  For many cooks and chefs the comparison depends on BThUs and KWHs and costs financially, but recent concerns over the consumption of red meats cooked and seared at high temperatures and risks of cancer have given the comparisons new turns.  Classifying cooking fumes as “probably carcinogenic” and “those produced during high-temperature frying are already known to cause cancer,” the report refers to high lung cancer rates among chefs in China, “which 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.”

2.  The researchers measured the fumes produced when frying 17 pieces of steak for 15 minutes each in conditions typical of Western restaurants, using margarine or 2 different brands of soya oil.  The results indicated that more naphthalene – a banned substance contained in traditional mothballs – and mutagenic alclehydes 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.

3.  The authors of the report 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 compounds for which there is no safety threshold, as yet.  However, “they appear to be higher with gas cooking.”  Exposure to cooking fumes “should be reduced as much as possible,” state the authors.

4.  Cooking fumes are thought to cause lung cancer, as well as cancers of the bladder and cervix.  Previous research has found that cancer levels are highest  among chefs who did not have fume extractors in their kitchens than among  those who did.  Altho smoking is the main cause of lung cancer in most countries only 10% of  the  women in Taiwan with lung cancer smoke.  However, 86% of Taiwanese men with lung cancer smoke. Exposure to cooking fumes may account for the high rates of cancer in women, who run the higher risks from smoking.  A study by researchers from the Institute of Medicine at Kaohsiung University in Taiwan published in 2000 in the American Journal of Epidemiology found that the longer women spent  cooking food, the higher the risk of lung cancer.  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.

5.  Any cooking of raw materials containing proteins and carbohydrate components is likely to set off browning reactions of the Maillard type.  Meat or bread heated to over 180°c is likely to undergo such changes, yielding in the case of meat carcinogens such as heterocyclic amines, among which is PHiP, a compound found also in fumes from burning plant material (as in smouldering tobacco).  Nitrosation of such amines in the gastric juices has been suggested as yielding highly carcinogenicnitroso – compounds.  However, other theories and other risks may arise according to the composition of the heated food: yields of acrylamide in breads and fried potatoes in various utensils and at different temperatures of frying, grilling, and toasting are likely to complicate matters, but the risks lessen appreciably if the heating by any method is kept below about 150°c and excessive browning and scorching are avoided.

6.  Cooking oils, especially from restaurants, can now be profitably disposed of as sources of fuel for driving machinery, which would include cars and vans.  In the first place repeated usage of cooking oils can lead to risky chemical reactions, from which emissions might arise of dangerous substances to be counted with other factors in assessing carbon footprints and atmospheric pollution.

7.  Our species is unique in routinely applying heat (as well as other means, such as microwaving and other forms of electromagnetic and nuclear radiation, in cooking – even toasting the crumpets by the fire for tea on a wintry day).

8.  Controlled fermentations may be other artifices in the processing of feeds and foods that may quite easily go wrong.




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