The dangers of antibiotics in animal feed

When Malaysian Health Minister Datuk Chua Jui Meng revealed that half the chickens sold in the country contained cancer-causing nitrofuran, it reopened a long-standing controversy over the widespread use and dangers of antibiotics in animal feed. Reviewing the debate Martin Khor explains why the use of such drugs in animal feed should be banned or tightly regulated.

IS it safe to consume chickens that have been fed antibiotics?

This question occupied the attention of Malaysians after revelation in August that half the chickens sold in the local markets may be contaminated with high levels of nitrofuran, an antibiotic known to cause cancer.

Health Minister Datuk Chua Jui Meng revealed that a Ministry survey found 51% of the chicken samples bought from various towns to contain nitrofuran at levels up to 4,000% above the Veterinary Department's guideline level.

Datuk Chua said his Ministry did not permit nitrofuran in chickens, and criticised the chicken industry for double standards in exporting nitrofuran-free chicken whilst selling unsafe meat locally.

The following day saw a response from the Veterinary Department, which oversees the practices of the livestock industry. Its deputy director-general Datuk Dr Anwar Hassan defended the use of nitrofuran. He claimed its level in chickens would be nil seven days after the feeding as it would be excreted.

The use of alternative antibiotics would raise the chicken price by 50 cents, and if chickens were bred in a microbe-free environment, an egg would cost RM14.50, Dr Anwar added.

The Federation of Livestock Farmers' Association claimed it would take a person 28,500 years eating chicken containing nitrofuran to contract cancer.

Consumer groups, led by the Consumers' Association of Penang (CAP) called for an immediate ban on the use of nitrofuran in animal feed.

The Domestic Trade and Consumers' Affairs Minister Datuk Abu Hassan Omar called for a safe level of nitrofuran to be determined to dispel public fear about eating chicken.

Datuk Chua, meanwhile, stuck to his point. He did not know how many years it would take for someone to get cancer from eating nitrofuran-contaminated chicken, but 'all chickens sold must be nitrofuran-free.'

The Veterinary Department allows the livestock industry the use of antibiotics. There is hardly any restriction or control on the sale or use of drugs in animals and animal feed.

On the other hand, the Food Regulations 1985 prohibits the presence of antibiotics in meat, meat products and milk.

Good reasons

This implies that whilst livestock farms are allowed to feed antibiotics to their animals, by the time the meat is sold in the markets they must no longer contain the antibiotics.

In theory, if the antibiotics are no longer fed to the animals several days before they are slaughtered, the medicines would all have been excreted, and the meat would be free from contamination.

In practice, as the Health Ministry test showed, half the chickens sold still had nitrofuran. Obviously the farmers had not followed the 'withdrawal schedule' and the drug had been given up to a few days before the chickens were slaughtered.

Nitrofuran is only one of the drugs used to feed chickens. If the tests had covered other antibiotics as well, the incidence of contamination would have been much higher. Maybe even 100%.

There are good reasons why the law prohibits antibiotic residues in meat.

In the case of nitrofuran, as Datuk Chua noted, there are stringent laws against its use in developed countries, and the Food and Agriculture Organisation does not stipulate any permissible level for it.

When no permissible level is set, the implication is that the substance is 'unsafe at any level'.

In the United States, the Food and Drug Administration ordered the poultry and pork industry to stop treating stock with two nitrofurans (furazolidone and nitrofurazone), citing cancer risks.

As early as 1984, CAP had called for a ban on nitrofuran and several other drugs in animal feed in Malaysia.

The nitrofuran scare is only the tip of a large iceberg. Many different drugs are used in the livestock industry, such as antibiotics (to treat illness and promote growth); hormones (to fatten and promote growth); steroids (to build up bulk and weight); tranquilisers (for anti-stress). Their risks to human health are increasingly being exposed.

The health risk is clear when a cancer-causing drug like nitrofuran is passed on from chicken meat to humans.

Other drugs used in animal feed can also have serious side-effects. For instance, residue of drugs in the penicillin family can cause allergic reactions in some people.

Neomycin, gentamicin, streptomycin can have toxic side-effects, such as deafness and kidney trouble after high doses and prolonged use. Tetracycline can worsen a kidney disease. Trimethoprim is not for the newborn or pregnant or people with impaired kidney function.

All the above drugs are found in animal feed and animal health products manufactured by multinational companies, sold in shops in Malaysia, and used in livestock farms.

Perhaps even more dangerous is that consumption of these antibiotics builds up resistant strains of bacteria in the animals.

These super-germs are resistant to antibiotics. When these resistant bacteria are passed on to people who consume the meat, they are exposed to diseases which would now become difficult or impossible to treat with antibiotics.

The World Health Organisation has recently sounded the alarm bell on the reemergence of deadly diseases caused by antibiotic-resistant bacteria.

Universiti Sains Malaysia's pharmacy professor, Dr Dzulkifli Abdul Razak, warned that nitrofuran in chicken could cause a build-up of antibiotic resistance in humans. 'Once there is a resistance to the drug, it would not be effective in treating an infection.'

According to a recent CAP book, The Revenge of the Killer Germs: 'If these mutant, disease-causing germs cannot be killed by standard antibiotics, then a simple illness they cause like food poisoning can become a killer.

'People who are most vulnerable - children, the aged or infirm - may die before doctors can find an antibiotic that works.

'Even if the resistant germs don't cause you to fall sick, they can nonetheless multiply in your body, and transfer their antibiotic-resistant factor to other unrelated bacteria in your body. Should you get an infection by other harmful germs which have acquired drug resistance, then antibiotic treatment may not work.'

Rampant use

CAP surveys through the years have found that there is rampant use of antibiotics in Malaysian farms to treat and to fatten chickens and pigs. They use a wide range of drugs, including standard ones commonly used on patients in clinics and hospitals.

Recent CAP tests also found many types of meat (chicken, beef, mutton and pork) containing super-germs that are resistant to antibiotics:

* 86% of bacteria samples from the meats were resistant to ampicillin, and 28% were completely resistant to it.

* 58% of bacteria samples were resistant to amoxycillin and 3% were completely resistant.

Both ampicillin and amoxycillin belong to the penicillin family of drugs and are widely used for a large range of ailments.

A finding that bacteria are resistant to the drug means that the antibiotic cannot kill the germs. This means the drug will also not work on people who are sick as a result of eating such bacteria-infected meat.

Earlier CAP tests on chicken, pork and mutton also found four strains of disease-causing bacteria resistant to common antibiotics.

* In chicken meat, penicillin failed to kill the E. coli bacteria and the drugs chloramphenicol and neomycin had little effect on E. coli and two other types of bacteria.

* In mutton, three types of bacteria were completely resistant to penicillin, while chloramphenicol and neomycin had little effect.

* In pork, the various kinds of bacteria were all resistant to penicillin; neomycin was almost useless against three bacteria strains; tetracycline and chloramphenicol had very little effect on the E. coli bacteria.

E. coli has been in the news recently as a particular strain of this bacteria (E. coli O-157) has caused Japan's most serious outbreak of food poisoning, in which over 9,000 people have been stricken and seven killed.

Given the growing evidence of the dangers, many countries have banned or severely restricted antibiotics in animal feed.

Australia, France and Switzerland are among countries that have banned the use of any antibiotics in animal feed. Australia and France also disallow the use of hormones.

The US has banned nitrofurans, chloramphenicol and ampicillin in animal feed, whilst Germany forbids penicillin and tertracycline, and the Netherlands has prohibited penicillin and tetracycline.

There is now more than enough evidence that self-regulation for safety in the livestock industry does not work.

The outbreaks of Mad Cow Disease in Europe and the food poisoning epidemic in Japan are warnings that cannot be ignored. Food safety of the public must come before profits of a few.

Martin Khor is the Director of Third World Network.