Two key themes, which have long been central to SFT concerns, stand out from this week’s newsletter. One of these is the safety of glyphosate – the world’s most widely used pesticide and the main active ingredient of more than 750 products, but best known as Roundup, the herbicide repeatedly sprayed on about three-quarters of all genetically modified crops. The other theme is antibiotic resistance.

What may surprise many of our readers, who will already be aware of longstanding concerns in these areas, is a scientific study finding a major link between the two, which we featured this week.

As reported in Eat the Week, the World Health Organization has concluded that glyphosate is probably a carcinogen. Clearly, direct exposure through spraying or spray drift will pose the greatest threat to human health, but it should be noted that in the United States, where glyphosate levels in food and water have risen in recent years, official residue limits have quietly been increased by as much as 25 fold to 40 parts per million for crops such as carrots, to ensure that current levels in food do not breach the regulations. This is alarming, because for known carcinogens, regulators do not normally permit levels as high as even one part per billion.

Also featured in Eat the Week, we link to a study that predicts that global use of farm antibiotics will increase by 67% within the next 15 years – the exact opposite of what is needed to reduce the threat posed by antibiotic resistance. Most of this increase is expected in developing countries and linked to rising demand for meat, but Peter Mundy, from Animal Welfare Approved, argues that the growing market for antibiotic-free milk and meat is not the way forward as it misleads consumers, won’t reduce the threat of antibiotic resistance much if at all, and will actually help to ensure the future of intensive livestock systems. What is needed instead, he argues, for human health and for animal welfare is robust legislation and enforcement, which ensures that antibiotics can be used when animals are genuinely ill, but prevents their widespread abuse.

However, the most surprising, and for many, most shocking news this week comes from a study by scientists at universities in New Zealand and Mexico. This finds that bacteria treated with antibiotics become resistant to them if there are low levels of glyphosate, 2,4-D or dicamba present at the same time. Perhaps the only good news about this discovery is that the levels of these three herbicides currently found in food are too low to trigger this effect. However, the scientists identify a number of situations where the occupational or environmental exposure of farm workers, children, farm animals and pets could be high enough to inhibit the ability of antibiotics to cure infections.

And, because these herbicides have been used for so many years it is also speculated that they may have been contributing to the rise of resistance over the years, which has been more rapid than expected.

Yet there is another link between the routine use of farm antibiotics and glyphosate, which is even less obvious. Antibiotics were first routinely allowed in livestock feed in the early 1950s, shortly after they had been developed. This essentially allowed farm animals to be taken out of fields and locked away in confined buildings and later feedlots. Before antibiotics this wasn’t possible as the animals got ill and died in these unnatural conditions.

This changed the face of agriculture because with the use of both fertilisers and herbicides it became possible to develop a continuous cropping system, which has run down soil carbon and structure, and caused major declines in biodiversity.

The introduction of glyphosate in the mid-1970s was arguably the next technological development to alter food production in such a fundamental way, because it allowed otherwise technically impractical crop rotations to become the norm. These continually take from the soil, and allow huge areas of monoculture to develop, with all their negative impacts. They have also allowed farm size to increase beyond the wildest dreams of earlier agriculturalists. This is taking the heart out of rural communities, reducing employment opportunities in agriculture and making it next to impossible for all but the super-rich to get a toehold in the countryside.

Photograph: NIAID

Sign up to our Newsletter

Stay up to date with the latest SFT views and news