Are we drinking cows' milk that is vastly deficient in vital nutrients because it has been exposed to artificial lighting? That is the fear being spread in a campaign by an American packaging company.
Page-length newspaper adverts are asking people: "Did you know recent studies show that indoor lights can degrade the freshness, taste and nutrients that we love in milk?"
It sounds disturbing. After all, families rely on the white stuff to provide such nutrients as protein and vitamins A (for the immune system and eyesight), D (for bones and teeth) and B2 (for healthy skin and nerves).
But what if half of that goodness isn't there, because the energy from light has destroyed the milk's delicate nutrients?
The company behind the adverts, Noluma, launched its publicity campaign in a trendy pop-up shop on London's Portobello Road last month.
The marketing initiative featured an on-site barista serving up " light-protected milk" in special packaging, surrounded by signs that proclaimed: "After 16 hours of indoor light exposure, milk has lost 49% of its vitamins."
In a YouTube video that the company posted, it erroneously shrank this to "just two hours".
The 16-hour figure seems to be based on a 2002 study by Cornell University in the US, published in the Journal of Dairy Science but the research only applied to skimmed milk.
Full cream milk is more robust, not least because it is more opaque. The Cornell researchers found that whole milk requires more than 50 hours' sitting under full light to show the same amount of deterioration.
Noluma says it is particularly concerned about the possible effects of energy-saving LED lights, which are being used in British supermarkets to replace fluorescent lamps. It argues that the light wavelengths emitted by LEDs are more damaging to milk.
But why such concern for our well-being? It seems hardly a coincidence that Noluma (a spin-off from the US chemicals giant DuPont) has invented a light-proof form of packaging for milk.
The company quotes research claiming that under LED lighting, there is a drop in vitamin D and protein after just 20 minutes, and the level of vitamin B2 falls by 28%.
The main source of its scientific claims is a report by Newcastle University entitled "Milk: Light exposure and depletion of key nutrients", which was commissioned by Noluma at a cost of £28 000 (R486 000).
The report is a review of previous studies and was not published in any scientific journal. In fact, the report did not meet Newcastle University's standards for research publication and in May this year the university asked Noluma to remove its brand from the publicity-campaign materials.
"The press release was written and promoted by the funder," a university spokesman told Good Health. "While the results are interesting, the report has not been subject to scientific peer review. As such, the study did not pass the standard required by Newcastle University."
Futhermore, while Noluma claims that modern LEDs are much worse than fluorescent lamps at degrading fresh milk, other research has shown the opposite. In 2016, Utah State University in the US compared the deterioration of milk exposed to LED and fluorescent lights.