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Wednesday, 29 September 1993
Page: 1454

(Question No. 548)


Senator Woodley asked the Minister representing the Minister for Primary Industries and Energy, upon notice, on 1 September, 1993:

  (1) Is the Minister aware of the statement by Bill Mollison in his book `Permaculture: A Designers' Manual' that 93 per cent of chickens in battery cages develop cancers.

  (2) Is the figure of 93 per cent correct; if not, what is the correct figure.

  (3) Has any assessment been done of the potential health implications to consumers of the presence of cancer in battery chickens; if so, what are the possible risks; if not, why not.


Senator Cook —The Minister for Primary Industries and Energy has provided the following answer to the honourable senator's question:

  (1) The Minister is aware of Mr Mollison's statement.

  (2) The figure of 93 per cent is not correct.

  The "correct" figure depends on the definition of "cancer" used. There are at least 100 different forms of cancer in chickens. The most common form, seen in birds of less than 22 weeks of age, is Marek's disease. The more common cancer in older birds is called leucosis. There is an effective vaccine for Marek's disease and commercial layer flocks are vaccinated, and in addition are from leucosis free stock. The frequency of leucosis in layers is less than 1%. Backyard and free range chickens also suffer from these cancers, usually at a much higher rate than commercial layers.

  (3) Most chicken meat in Australia comes from broilers slaughtered before 7 weeks of age. These birds have a low, even negligible cancer rate.

  Assessment of the potential health implications to consumers of the presence of cancer in battery hens shows that there is no association between the consumption of chickens in general and human health risk, and none between the consumption of battery hens with, or without, cancer.

  There are no risks because virus diseases of animals, including chicken cancers, are species specific. Very few virus diseases will cross species barriers, and then only between closely related species such as monkeys and man and sheep and cattle.

  The risk to consumers from eating chicken meat from battery hens is extremely low because, in addition to the species barrier, the meat is cooked before eating. Most bacteria and viruses are destroyed within a few minutes at 70(o)C. In addition the concentrated acid in the stomach and intestinal enzymes of the consumer will further degrade and inactivate viruses.