FOODStuff SA | New cold pasteurisation technique

06 Dec 2012 New cold pasteurisation technique

Posted at 12:39h in Food Science, Technology and Ingredients Stuff by admin 0 Comments

An American company has developed a technique that it says can make bread stay mould-free for 60 days. The bread is zapped in a sophisticated microwave array which kills the spores that cause the problem.

According to the company, MicroZap, its patent-pending technology utilises pulsed power of radio frequencies in the microwave spectrum. This unique process of pulsed power and multiple RF sources creates a targeted signal density to allow food to be pasteurised without damaging or changing its quality.

This combination of thermal and non-thermal effects destroys bacteria at lower (colder) temperatures, thus creating “cold pasteurisation” of fresh foods and eliminates deadly pathogens.

The company claims it could significantly reduce the amount of wasted bread – in the UK alone, almost a third of loaves purchased. The technique can also be used with a wide range of foods including fresh turkey and many fruits and vegetables.

World of waste

Food waste is a massive problem in most developed countries. In the US, figures released this year suggest that the average American family throws away 40% of the food they purchase – which adds up to $165bn (£102bn) annually.

Bread is a major culprit, with 32% of loaves purchased in the UK thrown out as waste when they could be eaten, according to figures from the Department for Environment, Food and Rural Affairs (Defra).

One of the biggest threats to bread is mould. As loaves are usually wrapped in plastic, any water in the bread that evaporates from within is trapped and makes the surface moist. This provides excellent growing conditions for Rhizopus stolonifer, the fungus that leads to mould.

In normal conditions, bread will go mouldy in around 10 days, but Microzap says it’s processing will keep the bread mould free for two months.

At its laboratory on the campus of Texas Tech University in Lubbock, chief executive Don Stull showed off the long, metallic microwave device that resembles an industrial production line. Originally designed to kill bacteria such as MRSA and salmonella, the researchers discovered it could kill the mould spores in bread in around 10 seconds.

“We treated a slice of bread in the device, we then checked the mould that was in that bread over time against a control, ” he explained.

“And at 60 days it had the same mould content as it had when it came out of the oven.”

The machine the team has built uses much the same technology as found in commercial microwaves – but with some important differences, according to Stull.

“We introduce the microwave frequencies in different ways, through a slotted radiator. We get a basically homogeneous signal density in our chamber – in other words, we don’t get the hot and cold spots you get in your home microwave.”

The company’s device has attracted plenty of interest from bread manufacturers – but it is worried that it could push up costs in an industry where margins are very tight.

And there is also a concern that consumers might not take to bread that lasts for so long. Stull acknowledges it might be difficult to convince some people of the benefits…..