There are a vocal minority of folks who simply don't want to drink pasteurised milk. Maybe they're worried about the nutritional content, or not getting the good bacteria they need. Sure, they're potentially subjecting themselves to tuberculosis or a Listeria infection, but it's still a vocal group.
One team of researchers from Texas A&M University is studying a way to pasteurise milk without heating it. They're inactivating the bacteria using equipment normally reserved for particle physics -- an electron beam. Maybe raw milk fans will be able to have their milk and drink it safely.
"Raw milk has harmful pathogens and we need to eliminate the harmful pathogens," study author Suresh Pillai, Director of the National Center for Electron Beam Food Research at Texas A&M, told Gizmodo. And "drinking raw milk for good bacteria is like playing Russian roulette".
Pasteurising milk is a quick process that simply involves heating the milk to 71.7C for 15 seconds, then cooling it quickly to kill the bacteria, as we've written about previously. Folks insist that the pasteurisation process decreases some of milk's nutritional value, and that drinking raw milk might confer some sort of protective effect against allergies or asthma. There's some evidence that the pasteurisation can affect proteins and vitamins, but not enough to lead to a nutritional deficiency. Nor is there much evidence to back up the protective effect, according to a review in Nutrition Today by University of Wisconsin food science professor John Lucey.
So rather than argue, Pillai's team has found a way to strip the milk of its harmful pathogens without heating it up. Milk goes into a bag (or on the commercial scale, through a pipe) and receives a uniformly distributed dose of nearly light-speed electrons from Texas A&M's Electron Beam Linear Accelerator. It's more or less a big version of the cathode ray tube found in old televisions.
Previous studies have shown that these beams can effectively inactivate the bacteria in the milk by snapping strands of their DNA. But Pillai and his team wanted to know how the electrons changed the nutritional content of milk samples.
After treating the milk, only the level of riboflavin noticeably decreased, by around 32 per cent after the full electron dose. But even the remaining riboflavin would make milk processed this way an "excellent source" of riboflavin, or more than 20 per cent the recommended daily value per the usual consumed dose. However, some of the milk fat did oxidise, the reaction that gives fats a rancid smell, though the treated milk didn't smell much different to the researchers.
The process also produced more than 20 volatile compounds -- compounds that can easily escape the liquid at room temperature and enter into your nose. Six of those have a smell associated with them, according to the study published today in the Journal of Food Science.
This process isn't ready for prime time yet, of course. Pillai and his team would want to analyse the produced volatile compounds to make sure they're safe -- and the process does give the milk a bit of a smell. "There are a lot of tests that need to take place," he said. Plus, you'd need to convince a raw milk drinker that the tradeoff -- safer milk that's a little chemically different but still technically "raw" -- is worth switching to. But Pillai did mention that all the inactivated bacteria in the milk could possibly boost immunity.
So, will someone start shooting milk with an electron gun to make it safer? Pillai hopes so. "We are hoping that someone will commercialise the technology," he said. "We don't expect the big companies to do this, but maybe small businesses."
Until then, Pillai wants you to drink pasteurised milk. "Other studies that show heat pasteurisation is the safest method." I just hope researchers keep putting things into particle accelerators.