It's greenish, it comes from milk, and it had Australians scratching their heads in 2012.
"Permeate" was the second-highest trending term in the "What is…" category of Google searches in 2012, according to the internet giant's annual Zeitgeist report released recently. The report tracks the year's top search trends, or queries that have experienced the largest increase in volume over the year.
Greenish in colour due to its high vitamin B levels, permeate is produced when whole milk is filtered through a very fine membrane. This process, called ultra-filtration, separates the lactose (or milk sugar), vitamins and minerals from the water, milk protein and fat in whole milk. The part containing the lactose, vitamins and minerals is called permeate.
A seemingly unlikely villain, permeate shot to national prominence in April 2012, when Fairfax's BusinessDay section revealed the “watery, greenish waste product” made up to 16.5 per cent of the whole milk produced by the country's largest milk producer, National Foods.
Citing “documents leaked by a whistleblower”, it calculated that this “dirty little secret” allowed the company to save just under 7¢ a litre in production costs.
The public reaction was as swift as it was angry. By June, major milk processors, including Pura and Dairy Farmers, had promised to stop adding permeate to their milk. Supermarket giants Coles and Woolworths followed in July, declaring their house-brand milk would also go permeate-free. Permeate-free labels proliferated, and worried consumers breathed a collective sigh of relief.
According to RMIT dairy scientist Frank Sherkat, however, the entire episode was an exercise in fearmongering. He says the ultra-filtration process has been used to standardise the components in milk since the 1980s.
“There's nothing wrong with Australian milk," Dr Sherkat says. "There never has been.”
He says manufacturers used permeate to standardise milk.
"So long as the permeate is intact, there is nothing wrong with that nutritionally.”
Moreover, he says, permeate is a natural component of milk and is present even in milk that is labelled permeate-free.
“Permeate is the water of milk … Permeate-free is the wrong expression," he says. "It's like saying orange juice is water-free. To talk about permeate-free milk is as if you are talking about milk powder.”
The difference now, he says, is that consumers buying milk without added permeate may notice "minor variations" in composition, according to the season.
Fairfax first picked up the permeate story in April 2008, and again drew attention to the issue in March 2011.
Ingrid Just, a spokeswoman for consumer group Choice, says the latest coverage came at a time when branded milk sales were falling.
“With food, people are passionate – and they get particularly passionate about milk," she says. "It's a key nutritional product, it's the first source of nutrition for babies, and they don't like it being played around with.
“[When] the media frenzy hit, branded milk companies started to realise that there was perhaps a point of difference for them in selling permeate-free milk … They were clever because they tapped into consumer sentiment at the time and into consumer fear.”
A 2011 Choice taste test of supermarket and premium milk brands found little difference between brands.
“If consumers want to choose permeate-free milk, then it's up to companies to put it on their label. From our perspective, there's no taste difference or nutritional difference,” Just says.
For Peter Haertsch, the man who claims to have "started it all" almost five years ago, the anti-permeate campaign was about getting a better deal for local dairy farmers.
"Woolworths and Coles ... were keeping their prices artificially low by getting the permeate at 1¢ a litre instead of getting the whole milk from me at 45¢ a litre," says Dr Haertsch, a plastic and reconstructive surgeon who also owns a dairy farm in Albion Park, New South Wales.
"We highlighted the permeate issue to highlight the problem with truth in advertising. The milk that was being sold as one litre of fresh whole milk in the supermarket was not one litre of the milk that was being taken at my farm gate ... The milk that left my gate ended up having permeate added to it."
He says that irrespective of whether or not the manufacturers behind branded milk later seized the permeate issue for marketing purposes, the outcome for farmers and the public has been positive.
"There is [now] some truth in the labelling ... the public now know what was going on," he says.
Both Coles and Woolworths told Good Food that all their private-label milk was now permeate-free.