Milk from cows fed on bracken 'carcinogenic'

Cows that eat bracken produce milk containing a potent carcinogen absorbed from the plant, according to new scientific research.

The carcinogen, ptaquiloside, would not be destroyed by pasteurisation, according to one expert. It is well known for its ability to cause tumours by damage to DNA, the basic genetic material of all cells. Now a team of scientists in New Zea- land and Venezuela has discovered that almost 10 per cent of the chemical eaten by cows is passed on in milk, a fact the team calls a "cause for concern".

The team suggests that ptaquiloside in milk is "certainly likely" to be responsible for the level of stomach cancer found in farmers in Costa Rica and other Central American countries, where bracken is particularly dense.

Though cows in the UK do not normally eat bracken, they may do if there is a drought, if fields have been overgrazed, or if they wander into thickets. The National Farmers' Union said: "Cows don't like to eat bracken, and farmers don't encourage its growth. Even in winter cows would be fed from winter stocks." But Alan Heyworth of the Bracken Advisory Commission said: "If the animals are in a field which has some fronds, it's obviously going to happen that they'll eat some."

The new research, published today in Nature, investigated the effects of feeding bracken to cows and discovered that ptaquiloside is still excreted in milk almost four days after feeding stops. Pasteurisation would be unlikely to affect the chemical, said Mr Heyworth: "If it survives getting through the cow's digestive system and blood, I don't think heat treatment would have any effect."

In the UK, the plant covers a total area equivalent to the size of Yorkshire. It is poisonous to animals which eat it, and its spores can be carcinogenic when fed to mice and guinea pigs. Although efforts are being made to destroy it using pesticides, European Union rules prevent spraying near watercourses - which can also be polluted by the plant.

Start your day with The Independent, sign up for daily news emails
Have you tried new the Independent Digital Edition apps?
ebooks
ebooksA celebration of British elections
  • Get to the point
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

SThree: Trainee Recruitment Consultant - Dublin

£13676.46 - £16411.61 per annum + OTE: SThree: SThree Trainee Recruitment Cons...

Ashdown Group: Marketing or Business Graduate Opportunity - Norwich - £22,000

£18000 - £22000 per annum + training: Ashdown Group: Business and Marketing Gr...

SThree: Trainee Recruitment Consultant

£20000 - £25000 per annum + Commission: SThree: Are you great at building rela...

Ashdown Group: Database Analyst - Birmingham - £22,000 plus benefits

£20000 - £22000 per annum + excellent benefits: Ashdown Group: Application Sup...

Day In a Page

Fishing for votes with Nigel Farage: The Ukip leader shows how he can work an audience as he casts his line to the disaffected of Grimsby

Fishing is on Nigel Farage's mind

Ukip leader casts a line to the disaffected
Who is bombing whom in the Middle East? It's amazing they don't all hit each other

Who is bombing whom in the Middle East?

Robert Fisk untangles the countries and factions
China's influence on fashion: At the top of the game both creatively and commercially

China's influence on fashion

At the top of the game both creatively and commercially
Lord O’Donnell: Former cabinet secretary on the election and life away from the levers of power

The man known as GOD has a reputation for getting the job done

Lord O'Donnell's three principles of rule
Rainbow shades: It's all bright on the night

Rainbow shades

It's all bright on the night
'It was first time I had ever tasted chocolate. I kept a piece, and when Amsterdam was liberated, I gave it to the first Allied soldier I saw'

Bread from heaven

Dutch survivors thank RAF for World War II drop that saved millions
Britain will be 'run for the wealthy and powerful' if Tories retain power - Labour

How 'the Axe' helped Labour

UK will be 'run for the wealthy and powerful' if Tories retain power
Rare and exclusive video shows the horrific price paid by activists for challenging the rule of jihadist extremists in Syria

The price to be paid for challenging the rule of extremists

A revolution now 'consuming its own children'
Welcome to the world of Megagames

Welcome to the world of Megagames

300 players take part in Watch the Skies! board game in London
'Nymphomaniac' actress reveals what it was really like to star in one of the most explicit films ever

Charlotte Gainsbourg on 'Nymphomaniac'

Starring in one of the most explicit films ever
Robert Fisk in Abu Dhabi: The Emirates' out-of-sight migrant workers helping to build the dream projects of its rulers

Robert Fisk in Abu Dhabi

The Emirates' out-of-sight migrant workers helping to build the dream projects of its rulers
Vince Cable interview: Charging fees for employment tribunals was 'a very bad move'

Vince Cable exclusive interview

Charging fees for employment tribunals was 'a very bad move'
Iwan Rheon interview: Game of Thrones star returns to his Welsh roots to record debut album

Iwan Rheon is returning to his Welsh roots

Rheon is best known for his role as the Bastard of Bolton. It's gruelling playing a sadistic torturer, he tells Craig McLean, but it hasn't stopped him recording an album of Welsh psychedelia
Morne Hardenberg interview: Cameraman for BBC's upcoming show Shark on filming the ocean's most dangerous predator

It's time for my close-up

Meet the man who films great whites for a living
Increasing numbers of homeless people in America keep their mobile phones on the streets

Homeless people keep mobile phones

A homeless person with a smartphone is a common sight in the US. And that's creating a network where the 'hobo' community can share information - and fight stigma - like never before