If you're like us, you'll probably have berries as a healthy, low carb addition to your healthy breakfast or dessert as a health win. That's why we wanted to talk about the current proposal involving pesticide residue on the berries we grow in Australia. You could have seen it in the news or on socials, and we want to tell you what it is and why you should pay attention. 

Essentially, the regulator for the pesticide industry is proposing to increase the permitted amount of a chemical called isocycloseram. They are aiming to allow a significantly higher amount of the residue of this chemical on our berries, meaning that more pest residue can remain on berries without it being illegal. The argument from regulators is that these levels proposed still remain safe. The argument from environmental and health campaigners like us is that the claims of safety require far more scrutiny. If you ask us, any increase in chemical pesticides should be strongly rejected...but nevertheless we want to educate you on exactly what's going on, so you can make up your own mind. 

Here’s a bit of a summary:

What is isocycloseram, the "forever chemical" in question?

Isocycloseram is a relatively new insecticide that has been developed by a company called Syngenta (a global chemical company). It's been used across the world in agriculture to control some of the more difficult pests such as thrips, mites, caterpillars and other insects. They're used on berries because these pests can seriously damage crops. 

The chemical works by interfering with GABA-gated chloride channels in an insect’s nervous system. Putting that into language we can understand, it essentially messes with the biological mechanism that helps switch nerve signals off. This makes the pest inactive, paralysed and eventually it will die. The chemical has been formulated to target insects and mites, rather than mammals. 

Now, how is this relevant to you? Back in 2021, Australia approved isocycloseram as a new active ingredient at a time when it had not yet been approved anywhere else in the world; from Europe to the USA. Products containing it were subsequently registered for use on Australian crops. The United States approved products containing the chemical in November 2025, while it is not currently approved for use in Europe. 

What is the Australian regulator proposing for berries?

Not only are we one of a segment of the world permitting the use of this chemical on our berries, but the APVMA (Australian Pesticides and Veterinary Medicines Authority) also sets maximum residue limits or MRLs. 

This MRL is the maximum level of a certain pesticide that can legally sit on food as a residue. It's important to note that it's not the same thing as a recommended dose or a permitted amount that a person can safely eat, however it's safe to assume they are linked. 

The proposal would change the limits of isocycloseram residue that could legally sit on berries from 0.01 milligrams per kilogram to:

• 3 mg/kg for bush berries, including blueberries and currants
• 5 mg/kg for cane berries, including raspberries and blackberries
• 0.7 mg/kg for low-growing berries, including strawberries and cranberries

The press has been widely commenting on these figures because they can represent a 300x increase for bush berries, a 500x increase for cane berries and a 70x increase for low-growing berries. 

Those numbers sound enormous. But they need some context.

Does a 500-fold increase in isocycloseram mean the berries are 500 times more dangerous?

Not necessarily, but environmental campaigners are saying the unknown is exactly the issue. 

The existing limit of 0.01 mg/kg is effectively around the level at which laboratories can reliably measure the chemical. Increasing this threshold from a very low starting point can therefore produce a dramatic-looking percentage without necessarily crossing a recognised health threshold.

For isocycloseram, the chemical in question, the APVMA established an acceptable daily intake using animal studies and applied a 100-fold safety factor to account for differences between animals and humans, as well as differences between individual people. The regulator says predicted dietary exposure from treated berries remains well below those health-based limits. 

Over the pond, our friends in America came to a similar conclusion, with the US Environmental Protection Agency saying that it found no human-health risks of concern when isocycloseram products are used according to their registered labels.

So this is not evidence that Australian berries have suddenly become poisonous.

It is, however, a legitimate reason to look more closely at how these decisions are being made. Just because a government makes this decision, does not mean it's safe, or in our best interest. 

Why are some people concerned? What should you look into?

One concern is the results of the toxicology studies...data doesn't lie. 

In animal studies reviewed by the APVMA, there definitely were effects that were seen at higher doses. Things like changes to the liver, testes and other organs, as well as some skeletal malformations. The APVMA also reported negative genotoxicity results and found no evidence supporting general neurotoxicity in the available studies. 

These findings on rats don't prove that eating berries from supermarkets and farms that spray the chemical will give the same effects in humans as above. The doses used were very high, and that is deliberate so that regulators can establish safety limited. 

My thoughts on this, and the position of others, is that when a chemical is new, persistent and potentially used across lots of different foods, regulators should take a very precautionary approach. This becomes especially important when it's impacting foods that children regularly eat like berries. 

Is isocycloseram really a "forever chemical"? 

Honestly, synthetic pesticides are rarely "good" and never "healthy", but those that stick around forever are the worst. And this part is hotly contested. Pesticide Action Australia describes isocycloseram as a PFAS pesticide under a broad structural definition used by the OECD. The organisation argues that the chemical can contribute to persistent breakdown products and should therefore be treated as a “forever chemical.” 

However, regulators do not all use the same definition of PFAS and argue against it. We call BS on this. The APVMA’s own environmental assessment states that isocycloseram is not readily biodegradable. That makes its potential movement through soil and water, and the behaviour of its breakdown, extremely important to assess before moving to any increases.. 

Can isocycloseram harm bees and other beneficial insects? 

The findings from APVMA testing is that isocycloseram is harmful to adult bees and, surprise surprise, is also very toxic to bee larvae. It was also highly toxic to certain beneficial predatory and parasitic insects. The regulator concluded that risks to bees should be acceptable under the approved conditions, including applying the product after bees have stopped flying and limiting application rates. 

Whether those controls are consistently followed, and whether they adequately protect pollinators across different farming conditions, is another question worth asking.

So what do we do?

This debate is bigger than one punnet of strawberries. It raises reasonable questions about how Australia assesses new pesticides, how much weight is placed on manufacturer-supplied studies, how cumulative exposure is considered, how forever chemicals are managed and whether regulators should wait for clear evidence of harm or act earlier when uncertainty remains.

You do not have to accept every alarming headline. You also do not have to accept every regulatory reassurance without question.

If you want your voice to be heard, submit this petition, and make sure you stay educated and up to date on the matter.