What's in our food: Is that a bug in your steak?

* In this second part of a week-long series on food, Herald science and health reporters research the truth about the food groups we reply on.

From fruit and vegetables, today's special focus on meat, a look at dairy products tomorrow and then grains and cereals followed by takeaways, we ask what is good for you these days.

New Zealanders are among the most carnivorous people in the world - and the experts say it is bad for our health.

In the past year the average Kiwi chewed through 45kg of cattle and sheep, 38kg of chicken and 20kg of pigs, making us the globe's fourth-biggest meat-eaters after the United States, Australia and Uruguay.

And it is no coincidence that heart disease accounts for 41 per cent of our deaths.

Meat is also implicated in most cases of food poisoning, and food safety campaigners look askance at the widespread use of antibiotics, pesticides and, to a lesser extent, growth hormones by farmers who produce our meat.

Yet meat is also an important source of the nutrients we all need.

Nutrients

Almost half our protein and a third of our fat and iron come from the meat food group, including fish and eggs. It is not, of course, essential. Vegetarians can get those nutrients from beans and other vegetables, fruit, nuts and cereals.

But the 1997 national nutrition survey found that at least 96 per cent of us eat meat, including 2 per cent who shun red meat but still eat chicken.

The same survey found that the amount of protein we take in is about twice what we need for men, and about two-thirds more than we need for women.

Men also eat too much fat and twice as much iron as they need, although women take in slightly less iron than the recommended level during their reproductive years, when they lose much of it in menstruation.

Ministry of Health advice is to eat just one serving a day from the meat group, such as one 120g steak, two slices of cooked meat, three-quarters of a cup of mince, one chicken leg or fish fillet, or one egg.

"A couple of fish meals a week, a bean meal a week, a red meat meal - it's the variety that's good," says dietitian Christine Cook.

Fish has extra benefits, with virtually no saturated fat and lots of omega-3 polyunsaturated fat, which reduces the risk of heart attacks.

"Canned fish is just as good as fresh fish, and is a cheaper option," says Cook's colleague, Pip Duncan.

But the kind of fat-coated fish you get in fish-and-chip shops, about 10 per cent saturated fat, is definitely not recommended.

Sausages are only slightly better, and many meat pies are even worse.

"A sausage meal with vegetables and potato is preferable to fish and chips," says another dietitian, Kate Sladden.

Similarly, she says, one egg dish a week would be a good cheap source of protein.

Otago University nutritionist Winsome Parnell advises people to look for lean meat and not to cook it in butter or fat.

Rather than serving huge lumps of meat, she recommends blending it with less fatty ingredients such as breadcrumbs in meatloaves and meatballs or beans in chilli con carne.

Chicken can be mixed with vegetables in stir-fries, or cooked whole in an oven bag.

Bugs

New Zealand's food-poisoning rate is the highest in the developed world. Listeria, campylobacter, salmonella and other bacteria in food killed six New Zealanders in 2002 and four last year.

A 1993 study found that 9 per cent of all adults suffered food poisoning in the previous year.

Bacteria evolved about 3 billion years before humans and largely created the atmosphere that allowed us to evolve. "Friendly" bacteria help our bodies to extract vitamins and other nutrients from food and help to fight off "unfriendly", or pathogenic, bugs.

These unfriendly bugs live in plants and in the soil around us, but in practice most of them get into our bodies through water and from other animals - our meat.

Campylobacter, a bug that causes bloody diarrhoea, stomach pain and nausea, has been found in between 52 and 68 per cent of uncooked chickens on sale in New Zealand supermarkets in three studies since 1995.

Listeria is rarer but more deadly, accounting for all four deaths from food poisoning last year. The bug has been found in 25 to 50 per cent of processed meats such as ham and luncheon sausage, and is dangerous to unborn babies.

The Dietetic Association warns that storing meat in the fridge is not enough to kill bugs, so it must be cooked thoroughly. Campylobacter, for example, is killed about 55C.

"The probability of contaminated product after cooking is low," says the Institute of Environmental Science and Research (ESR).

"General consumer advice for control of pathogens in poultry is to cook the food until juices run clear."

Antibiotics

Ever since Alexander Fleming discovered that the penicillin mould on his petri dish was killing the staphylococcus bug underneath it, numerous bugs have been used to kill other nasty bugs. They have transformed health in rich countries by giving us resistance to once-deadly diseases such as tuberculosis and cholera.

Almost as soon as such "antibiotics" became widely used on humans during World War II, vets and farmers noticed that they not only helped to make animals healthier, but also made them grow faster.

By 1999, 57 per cent of the antibiotics used in New Zealand were being used on animals - two-thirds of them mixed in with the animals' feed to promote growth and as a general disease-prevention insurance.

But this widespread use has bred new strains of bacteria that are resistant to antibiotics.

In response, the European Union is phasing out all use of antibiotics for animal growth by next January.

New Zealand has acted more reluctantly. Some antibiotics have been restricted to veterinary medical use only, but three types - ionophores, flavophospholipols and quinoxalines - can still be used in stockfeed on the basis that they are quite different from any antibiotics used in human medicine.

As a result, official figures show that antibiotics used for disease-prevention insurance in New Zealand stockfeed have more than doubled from 35.8 tonnes in 1999 to 84.7 tonnes in 2002.

Otago University microbiologist Greg Cook says one kind of antibiotic-resistant bug, VRE, has spread from chicken into 16 human patients reported in New Zealand so far. He estimates that 120,000 New Zealanders may have the new bug.

Christchurch microbiologist John Aitken found VRE and four other antibiotic-resistant bugs in a single chicken sampled for the Green Party in 2002.

He says he would still happily eat the chicken if it was cooked properly because cooking kills the bugs.

But antibiotic use in animals should be restricted to stop antibiotic-resistant bugs spreading into the human population when chicken is not cooked properly, he says.

Growth hormones

Many American beef farmers make their cattle grow faster by implanting capsules that release extra growth hormones such as oestrogen into the animals' ears.

The implants make the animals grow 7 to 17 per cent faster. But they also make some cows infertile. Some calves are also injured or killed when the hormones drive them to get ridden repeatedly by other calves.

The European Union banned hormone implants in 1989, mainly for animal welfare reasons.

They are still allowed in New Zealand, but are used by just 750 of the country's 32,000 beef and sheep farmers to produce beef for the US hamburger market.

The Food Safety Authority says there is no evidence that meat with extra hormones has any impact on human health.

Pesticides

Pesticides are relatively minor contaminants in meat, amounting to just one part in 24 million in rump steak.

The Dietetics Association says: "The risk of foodborne disease and malnutrition is 1000 times greater than that caused by natural toxicants or environmental contamination, and 100,000 times greater than illness caused by pesticides or additives."