Fresh cheese all the whey

Investigations into high pressure processing (HPP) technology could help open new export opportunities for manufacturers of fresh cheeses, which make up more than 20% of Australia’s annual cheese production.

Although a few HPP-treated dairy products have been commercialised so far, none are currently available in the Australian market. RMIT University’s Dr Hossein Daryaei graduated last year with a PhD examining ways to prolong the shelf-life of fresh cheese, without using artificial preservatives.

“My research showed that HPP, under optimised conditions, can effectively control the outgrowth of spoilage micro-organisms and further acidification in lactic curd cheeses during storage,” explained Dr Daryaei.

“Usually fresh cheeses last about three weeks in the fridge, but using HPP technology refrigerated shelf-life can be extended by up to up eight weeks, without the need for preservatives.

“These findings have much technological significance, and will help cheese manufacturers to expand distribution around the country, and take advantage of opportunities for exporting their products to new markets,” he said.

HPP involves subjecting food to intense pressures of up to 700MPa to inactivate microbial cells and viruses. Unlike heat treatment, HPP does not disrupt chemical bonds, so food treated with the technology tastes fresher and is more nutritious.

Dr Daryaei will now continue his research work at a post-doctoral position at the Ohio State University’s Food Science Department.

According Food Science Australia Innovative Foods Centre director, Dr Cornelis Versteeg, manufacturers who are interested in applying the research to their own processes should get in contact with the department.

The main challenge facing the technology lies in the associated costs of using the findings. “The barrier would be in having enough products to make full use of the equipment. In order to make it pay for itself, you would need to have full utilisation,” Dr Versteeg explained.

“The best way to start up would probably be to engage a contract processor, of which there are one or two around at the moment. Otherwise, the equipment cost is quite substantial for a small processor, so to have a reasonable unit cost, you’d need to have five shifts per week, and two per day.”

Food Science Australia Innovative Foods Centre researcher, Dr John Coventry, agreed. “We have facilities to do trial evaluations of products, and there’s also a toll processor available now in Victoria, which are actually manufacturing juice products, but are also available to provide that HPP service, so it can be accessed commercially. We can also do evaluation trials on products, ahead of any product development.”

Dr Coventry stressed that, alongside this research, “there are a lot of other projects in the HPP area, and if anybody outside of the cheese industry is interested in finding out if their products are suitable for HPP, they should get in touch to have their product evaluated and tested, and to see whether it is possible to give it a longer shelf life, eliminate preservatives, and remove listeria.

“The services we offer to the industry are designed to ensure that when manufacturers do make the decision to create a new product, they can be confident of being successful,” he concluded.

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