Blast wave research could prevent meat from spoiling


A technique involving a laser and an underwater explosion is being developed to lengthen the shelf life of raw meat according to researchers at the UNSW Canberra School of Engineering and IT.

Associate Professor Sean O’Byrne is part of a team funded by the Australian Meat Processing Corporation to develop a method for killing bacteria on meat that is more effective than pasteurisation.

“Bacteria colonies begin to develop as soon as meat is slaughtered in an abattoir, and so the meat has to be cleaned before it can be consumed by people,” Associate Professor O'Byrne explains.

“The common method for killing this bacteria is pasteurisation - spraying the meat with high pressure steam - and then putting it through a number of processes including vacuum packaging, which sucks the air out of the plastic packaging around the meat.

“This kills a lot of the bacteria on the meat that need oxygen to survive, but there are other types called anaerobic bacteria, and these ones will quite happily continue growing, which is why you can’t keep a piece of meat fresh indefinitely.”

As well as increasing shelf life, the meat industry want to investigate alternatives to pasteurisation that don’t affect the flavour of the meat.


Blasting bacteria cells

UNSW Canberra researchers believe that subjecting meat to high pressure then impulsively increasing and decreasing that pressure can burst the cell walls of the bacteria on the meat.

“The way you do this is by generating a blast wave in water,”Associate Professor O'Byrne says.

“If you explode something under water, a thing called a blast wave is produced and spreads out, and there’s very high pressure behind that followed by a very rapid reduction in that pressure.

“To generate that blast wave we focus a very powerful laser beam in water, and because it’s a laser we can focus it wherever we need to so we can control how big the pressure rise is and ensure it increases the pressure without heating the meat.”

The next step in the process has been to build a high pressure vessel with  windows to see the effect of the blast wave on the meat, which has proven challenging for the team, but can have broader applications once it has been developed.

“That’s the other technological part of the program: so not only are we developing a new method for treating meat samples, but we’re also developing new technologies for high pressure vessels where you can see what’s going on,” he says.

“And that opens up a whole bunch of other applications.”


Broader applications

 Associate Professor O’Byrne said one of those applications could be to examine the impact of underwater explosions on sea creatures.

“One of the areas of interest that hasn’t been studied much is looking at the effect of those blast waves at depth on fish or whales or other mammals,” he says.

“The effect of blast waves on people’s bodies if they’re involved in explosions is another area where there’s a lot of work that can be done, and this device provides a nicely controlled set of conditions that allow you to study that.”