Today in AgBioView from www.agbioworld.org - June 14, 2004:
* Organic food NON safety?
* GM fuss will be forgotten
* Biotech Industry Touts its 'Green' Credentials
* Roundup-ready canola is not an environmental threat
* Don’t worry, it’s organic
Organic food NON safety?
- Center for Global Food Issues, By Alex and Dennis Avery, June 11, 2004
The latest research from the University of Minnesota renews concerns that organic produce has higher bacterial risks than conventional fruits and vegetables. The Minnesota researchers found significantly more E. coli and more Salmonella bacteria on organic produce than conventional.
But the researchers themselves say don’t worry. They say that finding more E. coli bacteria on organic foods fertilized with manure doesn’t mean the organic stuff is more dangerous. Instead, it merely “supports the idea that organic produce is more susceptible to fecal contamination.”
Ah, well that’s reassuring, isn’t it? No really nasty E. coli, just more fecal contamination. Don’t you feel better now?
The Minnesota researchers are hiding behind technicalities and their epidermis is showing. They looked for E. coli O157:H7, the nastiest of the illness causing strains of E. coli, but didn’t find any. Instead they found only generic, non-pathogenic E. coli. Yet for decades, food safety authorities have used the increased presence of generic E. coli as a red flag for risk because the nasty strains are rare and so difficult to detect on produce.
The researchers themselves note that while medical detectives have “found very strong evidence” linking 19 E. coli O157:H7 outbreaks to specific produce, “very few have been successful in isolating O157.” Two other studies examining over 4,000 produce samples didn’t find any O157 either.
But we don’t have to consider hypotheticals. The researchers found real Salmonella on organic lettuce and green peppers but not on conventional foods. All Salmonella in food is potentially pathogenic. Doesn’t that mean that the organic stuff is more dangerous? No, say the researchers, because the prevalence of Salmonella in the organic foods was “very low.”
How low? They found Salmonella on 0.4 percent of organic samples (2 out of 476), making the organic foods in this study a 1 in 250 Salmonella crap shoot . . . er, lottery. Want to play? The jackpot is diarrhea, typhoid fever, and Reiter’s Syndrome that causes joint pain and painful urination that can last for years after the initial Salmonella infection.
The Minnesota group reveals their bias by making much of the fact that produce from certified organic farms had only 4.3 percent E. coli contamination compared to 11.4 percent for non-certified organic farms. On this basis, lead researcher Francisco Diez-Gonzalez says that “the good news is that if you are certified, you chance of fecal contamination decreases significantly.” Yet the certified organic contamination rate was still nearly three times higher than the conventional (although sample sizes were too small for this difference to be considered significant on a strictly statistical basis).
Organic food activists (including many activist researchers entrenched in liberal university halls) have claimed organic food superiority for years in their efforts to mold society and scare consumers into buying their politically correct fare. Now their farcical façade is crumbling.
Just last year, the UK’s Food Standards Agency tested 33 corn meal products for a cancer-causing fungal toxin called fumonisin. The European Union has established a new safety limit on fumonisin of 500 parts per billion. All six organic corn meals tested by the FSA failed the new standard, with an average contamination rate nearly 20 times the limit. Two were so heavily contaminated that they carried one third of the fumonisin dose known to cause cancer in laboratory rodents.
Four years ago, angry organic food activists tried to have John Stossel fired from ABC TV’s “20/20” for a segment he did highlighting the higher risks from organic foods grown in manure. But the concern about manure and bacterial contamination of organic foods was originally raised in 1997 by a physician with the Centers for Disease Control, in the Journal of the American Medical Association.
The Minnesota research along with previous research conducted at the University of Georgia indicates that current USDA rules fall far short of adequately protecting organic food consumers from bacterial risks. Why is it that organic consumers are still at greater risk seven years after the CDC first questioned the safety of organic manure use?
GM fuss will be forgotten
- The Border Mail (letter), Jun 14, 2004
IN response to letters published recently on genetically modified organism technology, I believe in 50 to 100 years time people will be wondering what all the fuss was about, because GMO-derived foods will be the norm, whether they are labelled GMO or not.
The many arguments used against GMOs today were used when hybrid crops were introduced 100 years ago and nobody gives a second thought to eating food derived from a hybrid crop, even without labels.
The arguments used then were, hybrid plants are not natural, plants cant survive by producing sterile seed and growers will be captive of the nasty multinational seed companies to buy their seed every year.
Not withstanding, the comments made by Patricia Bowen (The Border Mail, June 4) were incorrect, because the technology providers for GMO canola have stated, there will be no closed loop systems and farmers can keep their own seed.
I dont argue the reason Monsanto and Bayer want to be able to commercially release their GM canola is to make money; they are not taxpayer-funded, non-profit organisations and are no different to many of the companies who provide our non-GMO seed now, private enterprise, profit-driven companies.
Consumer reaction to GMO foods in supermarkets is very different from the results of polling.
Naturally, when asked whether they would prefer GMO to non-GMO products, a majority of consumers say non-GMO. It is a different story when they are actually buying food.
Where food is labelled as to whether it is GMO or not, an equally large majority choose GMO because they base their choices on price and quality and GMO can produce food at lower cost of production, with improved nutrition and quality.
I would like to think GM food will be widely accepted by consumers in the not-too-distant future and we can adopt this new technology as we have many others in the past, with a result of providing better, cheaper and healthier food, enabling Australian farmers to continue in the forefront of world agricultural production.
chair, Grains Committee
NSW Farmers Association
Biotech Industry Touts its 'Green' Credentials
All Things Considered audio
June 11, 2004
The biotech industry is a regular target of environmentalist activists over the issue of genetically modified foods. Now, biotech is trying to promote its "green" credentials through the development of biodegradable plastics and environmentally safe enzymes. NPR's Laura Sydell reports.
Listen to the report at:
Roundup-ready canola is not an environmental threat
- Times Colonist (Victoria), June 12, 2004, VIA AGNET
Robert Wager of Malaspina University-College, B.C. writes regarding, "Farmers should be allowed to save seed," June 1, to say that court records show that Percy Schmeiser did not spend a lifetime saving canola seed but in fact purchased new varieties every few years.
They also show how Schmeiser sprayed three acres of his crop with Roundup and then saved the seed from plants that survived for planting the following year. This resulted in 1,030 acres of 95-98 per cent Roundup-ready (RR) canola spread over seven fields. To suggest the seed blew into his seven fields of over 1,000 acres is completely contrary to the court records. This is why he was found guilty by all three levels of the Canadian court system.
The suggestion that RR canola is a threat to the environment does not stand up to scrutiny. In fact the wide adoption of herbicide resistant canola (by 70 per cent of farmers in this country) has reduced tilling of the soil, so saves topsoil and greenhouse gas from tractor exhaust, replaces older herbicides which had greater environmental impact and allowed the farmer to make a better profit.
To suggest that 70 per cent of Canadian farmers don't know or understand these technologies is insulting to the farmers and is not backed up by research. There is a great deal of mis-information about genetically engineered crops and the public must be careful when reading the negative stories as almost all are untrue.
Don’t worry, it’s organic
- Chemistry World Issue 6, by Maria Burke
According to public perception, organic food is the more heathy option. But is this always the case? Maria Burke looks at organic farming and explodes a few popular myths
-- Organic farming is a multi-million pound industry that relies on the public’s perception that organic food is more healthy
-- There is little evidence to suggest that organic fruit and vegetables are any healthier than conventional produce
-- Some forms of organic farming may introduce natural toxins into consumers’ food
Sales of organic produce are booming. Just look at the baby-food market, for example, where organics now account for 70 per cent of UK sales. The organic industry’s message of safer, healthier food produced using farming practices that are gentler on the environment is falling on receptive ears. But critics take issue with many of the industry’s claims, arguing that organic fruit and vegetables are more likely to be contaminated with potentially dangerous bacteria and mould toxins. And they point out that higher levels of natural ‘pesticides’ found in organic produce could be just as dangerous as synthetic chemicals if eaten at high enough doses. So just how safe are organic fruit and vegetables?
Several years ago, critics suggested that organic produce was more likely to be contaminated with bacteria that can cause food-poisoning and worse. Raw manure applied to soil can contaminate crops with pathogens such as Escherichia coli (E. coli), shigella and salmonella, according to Mike Doyle, a microbiologist and director of the Center for Food Safety at the University of Georgia. They come from the stomachs of animals like sheep, cows and deer, and are shed in their manure. Once in the soil, they can transfer to the plants, or they can contaminate water used to irrigate or wash produce. Most farmers have developed antibodies to these infections, but they can kill the elderly or very young, or cause kidney damage.
Research conducted by Doyle’s team has shown that E. coli O157 can persist in soil containing compost or contaminated water up to six months. ‘The duration of contamination by E. coli O157 on produce grown in these fields varied depending on the type of produce. Greatest persistence (around 170
days) occurred on parsley and carrots, whereas least persistence (around 75 days) occurred on onions and lettuce’, he comments.
Scientists have also shown that pathogens can get into the plant itself. Karl Matthews and his team at Rutgers University, US, showed how E. coli could transfer from manure and contaminated water into the inner tissues of organic lettuces, where it was protected from sanitising agents.1 The bacteria passed through the roots and entered the edible portions of the plant. However, the team introduced E. coli into the compost at rates far higher than would normally be found in nature.
Considering the amount of produce consumed, there is a significant risk to consumers, says Doyle. ‘But if manure is properly composted or aged, then the risk of contamination of produce is likely to be low. Conventional farming that uses manure to fertilise fields poses the same risk as organic farming. The risk largely depends on how the manure is composted and handled before application to the soil.’
James Cleeton, policy project coordinator of the Soil Association, one of the UK’s two organic accreditation organisations, believes organic produce has a lower risk from bugs like E. coli because organic farmers have to comply with manure-handling standards, but conventional farmers do not. Organic farmers in the UK are prohibited from spreading raw manure onto crops during the growing season. Composting – heating heaps of manure to 60 °C – greatly reduces pathogen loads, he says. ‘All manure used on organic farms should be composted for a minimum of two months or stacked [left in piles] for three months prior to application, and there should also be a minimum three month period between application and harvest.’. He adds ‘If fresh manure is used, organic farmers are directed to leave a six-month interval between application and harvest. If slurry is used, this is increased to one year.’ In addition all organic farmers are inspected once a year by their accreditation organisation.
Caroline Smith DeWaal, Food Safety Director for the Center for Science in the Public Interest, a Washington DC-based consumer health group, agrees that organic growers’ use of composted manure reduces pathogen risk dramatically. She says: ‘Organic producers certified by the USDA [US Department of Agriculture] must use composted manure, although there are no similar requirements for other growers. The use of uncomposted manure on non-organic farms is not regulated in the US and it can clearly pose a significant risk.’ The USDA’s National Organic Standards Board states that raw animal manure can only be applied to land growing a non-food crop or if harvesting takes place 90-120 days after application, depending on the crop. There are detailed requirements for composting conditions, including the temperatures heaps should reach, how long the heap should be heated and how often the heap should be turned and aerated.
But are the regulations robust enough to prevent pathogen transfer? Mike Doyle’s team has revealed that, under ‘worst case scenarios’, Salmonella and E. coli O157:H7 can survive in soil for around 210 days. ‘This would suggest that harvesting vegetables 120 days after application of raw manure may not be safe under some circumstances,’ he adds.
What’s more, Tony Trewavas, a plant biochemist at the University of Edinburgh, points out that during composting, the required heat may not be maintained in the outside portions of the heap, allowing pathogens to survive. He also adds that when manure is composted, it can lose up to half of its nitrogen content as ammonia, reducing its fertilising powers and probably resulting in a reduced crop yield. ‘Conventional farmers can use minerals to revitalise their soils so it matters less to them, but there may be a temptation for organic farmers to compost for less time. It all depends on trust.’
Any manure-based agriculture requires sophisticated analysis of produce for bacterial and mould toxin contamination, says John Hillman, director of the Scottish Crop Research Institute. ‘Does composting work? I have grave doubts, but there is an absence of good quantitative data. We need robust monitoring. But this can be a problem as the bulk of organic produce is imported [to the UK] and it is easy to cheat.’
Trewavas believes that, while organic and conventional crops are probably equally at risk from pathogens in the UK, this is not the case in the US. ‘Conventional farms in the US are traditionally much larger and farmers can’t manure such huge areas,’ he explains. ‘There, the risk is, therefore, greater from organic crops because manure is mainly applied by owners of small organic farms.’
Dennis and Alex Avery of the not-for-profit Center for Global Food Issues, part of the Hudson Institute in Virginia, US, also think that the risk from manure is mainly associated with organic farming. When conventional farmers use manure, it is mainly on crops that are milled and cooked, they point out. They stress that while conventional farmers are not governed by national regulations, all states have manure-handling regulations for food crops. They worry that organic farmers may not comply with regulations, and doubt the efficacy and robustness of the US system of inspection by independent organic certifiers.
The official line
So are organic crops more likely to be contaminated with bacteria because growers use more manure, or less likely to be contaminated because growers abide by strict regulations for handling the stuff? According to the UK Food Standards Agency (FSA), there is no firm evidence one way or the other. It states: ‘The microbiological safety of food depends essentially on controlling the hazards that arise in production and preparation. Good management of manures, including the use of composting and appropriate timing and application, can significantly reduce risks. This applies equally to organic and conventional agriculture.’
Another area of concern for organic-sceptics is contamination with toxic substances produced by moulds called mycotoxins. The Averys say this is more of a worry than bacterial contamination. Crops damaged by insects or weather are vulnerable to a range of moulds. These moulds can produce toxins that contaminate the crop, either as it grows in the field or in storage. The most toxic are aflatoxins, which can induce liver cancer at very low doses if ingested over a prolonged period of time.
‘The risk from mycotoxins is much higher for organic produce,’ say the Averys, ‘because organic farmers use fungicides that are not as effective as the conventional equivalents.’ What’s more, organic farmers tend not to use any fungicides once the harvested crop is stored.
The Averys cite a FSA survey last year of 30 organic and conventional maize meal samples.2 It found ten samples were over the ‘action limit’ for a mycotoxin called fumonisin, six of which were organic samples. They were all withdrawn from the shelves. Two of the samples measured contained approximately 16,000 ppb of fumonisin. Currently, there is no legal limit, although a EU limit of 1000 ppb is under discussion. However, the FSA stresses that it was ‘unlikely’ that these products posed ‘a significant risk to health’.
The organic lobby rejects the Averys’ concerns. Cleeton argues that organic produce is less likely to be contaminated with mycotoxins because it is less prone to fungal attack. He explains: ‘Conventional crops are fed nitrates. These have been shown to stretch plant cells, making them more prone to damage and more vulnerable to fungal growth. This is not the case for organic crops.’
The UN Food and Agriculture Organisation, which published a report on food safety in organic farming back in July 2000, also takes the line that organic farming does not lead to an increased risk of mycotoxin contamination. It stresses that good agricultural, handling and storage practices minimise the risk in both conventional and organic farming.
Once again, the FSA finds no evidence to support a higher risk from organic food. Furthermore, it adds that the EU’s Scientific Committee on Plants has advised that there is insufficient evidence to show whether anti-fungal chemicals are effective in preventing moulds producing mycotoxins anyway. In the mean time, the FSA has commissioned a five-year study at Harper Adams University, UK, to examine the effect of environmental and agronomic factors, including organic farming, on the mycotoxin content of wheat, barley and oats.
Good phenols? Or bad?
Another contentious issue relates to compounds found in plants called secondary phenolic metabolites. Plants produce these natural toxins usually at very low levels to protect themselves against attack by pests or as a response to other sources of stress. Plant tissues may contain up to several grams per kilogram of these phenolic compounds, such as resveratrol, flavonoids, and furocoumarins. The organic lobby claims that their produce contains more phenolic compounds than conventional produce, and this makes their food better to eat. But the organic-sceptics argue that these natural pesticides may be a potential health risk and insist that there is no evidence to show health gains from organic food.
Cleeton quotes a raft of research showing that organic fruit and vegetables contain more phenolic compounds than conventionally farmed equivalents.3,4 Their theory is that because conventionally grown crops are protected by synthetic pesticides they don’t need to rely so much on their own defence mechanisms, which include phenolic compounds. But others point out that, because of restrictions on pesticide and fungicide usage, organic farmers are more likely to select varieties with greater resistance to pests or disease. The farming practices employed may be irrelevant.
But the more contentious claim from the organic lobby is that because these phenolic compounds are antioxidants, organic fruit and vegetables are better at protecting the body from cancers and coronary heart disease than their conventional equivalents. ‘The health benefits of high levels of antioxidants in the diet is well-documented,’ insists Cleeton. ‘There is a growing concern that levels of some phenolics may be lower than is good for human health in conventionally grown foods.’
Trewevas, meanwhile, is clear that there is just not enough evidence to demonstrate health benefits of phenolic compounds, or health gains from eating organic food. ‘It is irresponsible for the organic lobby to make any such claims. Just because these products have antioxidant activity does not automatically make them useful. For example, flavonoids are phytooestrogens and will induce mutations in rodents at high concentrations. We don’t know what they do in humans at the low levels we consume.’
The Averys agree that there is a lack of knowledge. ‘The notion that phenolics are antioxidants, and therefore all phenolics are healthy is seriously suspect. When betacarotene, a plant-produced anti-oxidant, was administered to smokers to reduce cancer risks, they actually increased the risks and the study was halted early. We simply don’t have nearly enough information to say that 20 per cent or 60 per cent more of ‘phenolic’ chemicals [a complex soup of many different phenolic chemicals with varying purposes] is healthier. We don’t have enough information to state that diets high in ‘antioxidants’ are healthy. We don’t really know what is in fruits and vegetables that makes them so healthy in our diet. That’s what everyone is trying to find out. But there is no evidence that eating organic fruits or vegetables is any healthier than eating other fruits and vegetables.’
So what line does the FSA take? On the first claim, it says that there is insufficient data to prove whether levels of phenolic compounds in organic produce are greater and occur more frequently than in conventionally produced foods. It states: ‘The presence of these chemicals in fruit and vegetables varies considerably, depending on a range of factors that include farming practices. For nutrients for which there is data available, the range of concentrations found tends to be both very wide and comparable for both organic and conventional produce.’ On the second claim, it stresses that although phenolics are known to be antioxidants, they are also known to inhibit iron absorption. ‘The impact of polyphenol consumption has not been fully evaluated. On the basis of current evidence, the overall FSA view is that organic food is not significantly different in terms of food safety and nutrition from food produced conventionally.’
There is some research that has raised concerns over the effects of phenolics, pointing out that some have potential mutagenic, carcinogenic and phototoxic effects.5 Take psoralens, for example, a group of furocoumarins found in celery, parsnips, dill, parsley and lime peel. Disease-resistant celery possesses high levels of furocoumarins concentrated in the leaf sap and stem sap. According to the US Center for Diseases and Control (CDC), contact with psoralens – or vegetables containing them - followed by skin exposure to sunlight can produce a variety of skin complaints ranging from burn-like blisters to eczema. While sunlight is enough to trigger this phytophotodermatitis, the artificial ultraviolet light in tanning salons makes it worse. However, there’s little risk from eating furocoumarins, according to the UK Committee on Toxicity (COT). But it does recommend monitoring new strains of furocoumarin-containing plants.
At the moment, in the UK, organic producers are forbidden by both the FSA and Advertising Standards Authority to claim that their food is more healthy or more nutritious because there is no evidence to substantiate the claim. Nevertheless, this does seem to be what organic producers believe. On the other hand, the authorities also consider as unproven many of the concerns over the safety of organic food. But many critics remain adamant that science shows there is a significant potential for risk.
So the debate over organic food rages on. It is a highly contested and controversial area, encompassing, as it does, sensitive political issues, strongly-held personal convictions and substantial economic opportunities. But all the protagonists do agree on one important point: eating five pieces of fruit and vegetables protects against cancer. Perhaps, as Caroline Smith DeWaal points out, the over-riding message is that all produce – whether organic or conventional – poses a higher health risk than previously realised, a risk that is up there with the higher profile dangers associated with beef and poultry. As consumers, it seems the best we can do, while the two sides fight it out, is to tuck in to plenty of fruit and vegetables, and make sure we wash it all properly, organic or otherwise.
Maria Burke is a freelance science writer from St Albans, UK.
1. Karl Matthews et al, Appl. Environ. Microbiol., 2002, 68, 397–400
3. Alyson Mitchell et al, J. Agric. Food Chem., 2003, 51, 1237–1241
4. Susanne Bugle et al (J. Agric. Food Chem., 2003, 51, 5671–5676
5. Otto Daniel et al (Environ. Health Perspect., 1999, 107(Suppl 1), 109–114