We dish the dirt on GMOs, hormones, antibiotics, and chemical toxins, and how you can protect yourself.

Testing of Australian-produced food consistently reveals that it’s safe – at least in terms of not exceeding designated chemical and drug residue limits. The big question, though, is whether any level of residue is safe, given the number of chemicals used in conventional farming and the fact they are only tested individually, never combined.

Genetic modification (GM)

A recent Archives of Toxicology study shows Roundup® is actually more toxic than its constituent ingredients, and is capable of damaging DNA in a human cell line when diluted to significantly lower concentrations than presently used in GM agriculture. The researchers say it has "genotoxic effects after short exposure to concentrations that correspond to a 450-fold dilution of spraying used in agriculture." It’s thought the surfactant polyoxyethyleneamine in Roundup® may be responsible for increasing the toxicity of glyphosate, due to its action of reducing surface tension between the herbicide and the cells exposed to it, making the cellular membranes more permeable to absorbing the glyphosate and other chemicals in the formula.

A major issue with GM is that many crops are bred to withstand Roundup®, which enables farmers to kill weeds by spraying the entire field. Since the first days of GM agriculture, concerns have been raised about the risks of this leading to overuse of Roundup®, and the associated effects on the land, environment and humans. Indeed, stories of weed resistance and ‘super weeds’ soon emerged. According to a recent report, in the USA alone the increase in herbicides required to deal with tougher-to-control weeds on land planted with GM crops has grown from 680,000 kilograms in 1999 to about 40 million kilograms in 2011.

The herbicide’s genotoxicity, carcinogenicity, and endocrine-disrupting actions are the biggest concerns. Glyphosate’s carcinogenicity was first identified in 1999 in a Swedish study that linked it to non-Hodgkin’s lymphoma. Monsanto denies the cancer connection, along with more recent findings that glyphosate causes liver damage, miscarriages, and affects human DNA.


While Australia remains largely GM-free, glyphosate is one of many chemicals that enter our food, given that Roundup® is the world’s highest-selling herbicide. Dianne Loughnan, beef producer and author of Food Shock, says that beef, cattle, sheep, pigs and poultry are routinely dipped, sprayed and injected with chemicals – many of which are toxic to humans in large amounts – to control worms, lice, ticks and flies that spread disease and can harm the animals. Farmers insist these procedures are essential to produce meat fit for human consumption. On top of this are the pesticides and herbicides sprayed on pasture, which the animals ingest while grazing.

The National Residue Survey (NRS), which conducted some 600,000 tests on 21,142 random samples of 48 animal and plant foods, revealed only minuscule amounts of glyphosate appeared as residue in food, well below the maximum residue limit. According to the NRS, Australian food is very safe. Horticulture, aquaculture – including wild harvested fish - and honey were clear of residues above safe, acceptable limits, while grain was 99.2 percent clear, Australian meat 99.86 percent clear, and eggs 99.26 percent clear. Underscoring these results was the FSANZ twenty-third Australian Total Diet Survey of 92 foods: this bi-annual survey consistently shows contaminant residues as very low, and always within safe limits.

However, the big question, says Loughnan, is what exactly is ‘safe’? Many experts believe there is no such thing as a safe level of pesticide residue. Loughnan explains that while the Australian Pesticides and Veterinary Medicines Authority (APVMA) tests individual active product ingredients, the entire formulation is not tested. According to the National Toxics Network, the active ingredients can react with additives like surfactants and solvents without the regulators’ knowledge – with the Roundup® research a clear illustration of this. Plus, Loughnan adds, much of the research into pesticides has been carried out by scientists working for, or consulting to the companies that make the, which introduces a bias to the debate.


The number of tonnes of antibiotics Australia imports 700 tonnes of antibiotics annually. Of this, 550 tonnes are used in livestock production, as medicine or growth promotants. There’s no question that the responsible use of antibiotics – and vaccines – to treat and prevent sickness in livestock guarantees healthy and disease-free meat. However, there are questions about their use as growth promotants: they’re given to birds and meat animals to promote more efficient feed conversion and speed up muscle growth, by controlling bacteria that can interfere with the gut’s ability to absorb nutrients. Less food is required, which means less waste is produced.

Increasing consumer awareness of the risks of antibiotic resistance has resulted in this practice being scaled down since the 1970s, according to the Australian Chicken Meat Federation. Loughnan says chicken producers now use a whole range of alternative growth promotants, both chemical and natural, the latter include holy basil, Indian gooseberry, neem oil, yeast cultures, vitamin and mineral supplements, probiotics, enzymes, microflora enhancers, and beta agonists.


Hormonal growth promotants (HGPs) are approved for use in pork and beef by the APVMA, and are used in all states except Tasmania. HGPs are not permitted in lamb, chicken meat and egg production, or in the dairy industry. In Europe, HGPs are banned from use in all meat-producing animals.

Loughnan writes that 40 percent of Australian beef supplied to domestic and export markets is treated with these synthetic hormones, which have been used in Australia since 1979 as a way to boost production. A pellet containing a form of oestrogen, progesterone and testosterone is implanted behind the animal’s ear, releasing a low dose of hormones over 100 days, and enabling the animal to grow faster by converting feed to muscle more efficiently. Porcine somatotrophin is the growth promotant used in the commercial pork industry, injected to produce fast growth and a lean carcass. It may be used in conjunction with non-hormonal growth promotants such as the beta-agonist ractopamine, which is added to feed. Other hormones are used to regulate sows’ breeding cycles. Chemicals are tested individually, never in combination, so no one knows what effects a cocktail of chemical residues in food may have.

The industry, FSANZ, APVMA and other bodies insist that growth hormones are safe for humans. However, consumers are not convinced, evidenced in Coles supermarkets’ recent shift to hormone-free meat. In the US, the American Public Health Association (APHA) is lobbying the FDA to ban hormone use. Their concern is that hormones originating outside the body can interfere with human hormone function, and that the oestradiol components in particular have contributed to hormone-related cancers such as breast and cervical cancer. Foetuses and children are thought to be more vulnerable to these endocrine disrupters, which APHA believes increase their risk of cancer and other diseases.


The phasing out of the highly toxic pesticides dimethoate and fenthion, traditionally used as post-harvest treatment for tropical fruit fly, has led to nine tropical fruits - mango, pawpaw, lychee, longan, mangosteen, rambutan, carambola, breadfruit and custard apple – being approved for irradiation, despite continuing consumer opposition. More approvals are pending.

In 1998, consumer resistance to irradiation resulted in a 10-year moratorium on the practice in Australia. In the interim, according to Friends of the Earth, irradiation was used on a range of non-food products including packaging, bee hives, herbs, pharmaceuticals, medical products, pet food, therapeutic goods, wine corks, cosmetics, and cereals and grains fed to meat animals. Consequently, by the time the moratorium was lifted, the nuclear irradiation industry was well-entrenched, with plants in Melbourne, Sydney and Brisbane.

Irradiation involves exposing food or other products to ionising radiation to destroy insects and bacteria, and so extend shelf life. Australian irradiation plants use gamma radiation from a nuclear by-product, cobalt-60, produced in Canadian nuclear power reactors. A major concern is the lack of long-term studies investigating the impact of irradiated foods on humans. Validating these concerns is the fact that irradiated cat food is now banned in Australia after more than 80 cats developed neurological disorders linked to consumption of irradiated cat food during 2008/9.

Despite this, rules have been amended to support interstate trade of irradiated foods. FSANZ states that a food package that has been irradiated, or food that contains irradiated ingredients, must carry a statement that it has been treated with ionising radiation. This also applies to food not otherwise required to carry a label, including: whole fruits sold loose, restaurant meals containing irradiated ingredients, takeaway pizza made with irradiated herbs, and curry made with irradiated spices. In the absence of a label, the statement must be displayed near the food.

Because the safety of these additives is unclear, the best option is to minimise your exposure by growing as much of your own food as you can, buying organic wherever possible, or buying from vendors at farmer’s markets who use chemicals responsibly.