First N.Z. Food-drying Unit Begins Operation

Press, Volume CI, Issue 29746, 13 February 1962, Page 15

First N.Z. Food-drying Unit Begins Operation

7 ’ ealand ’ s first accelerated freeze-drjnng unit began operation t M the fre ® zln £ works of the Alliance Freezing Company (Southland), "J“i’ ne Y In I vercar^ill > yesterday. The process is reputed to be the most modern development in food dehydration.

Eight hours after it had gone mto the unit, which is worth about £22,000. 2001 b of beef mmce emerged as 671 b of dehydrated product. The general manager of the company (Mr J. B. Grant) said last evening that the Jib squares of mince in dehydrated form looked like slices of toast with a slightly red colour, with about the same weight and consistency as a piece of toast.

The pieces, which were about sin long, 2J in wide and l:n thick quickly returned to their original structure when they were put into cold water, said Mr Grant.

Mr Grant said it was hoped to process another 2001 b to 3001 b of products of various types today, including some -teaks, after which a decision would be made as to what products the plant would produce.

New Possibilities The proress may provide a new means of marketing New Zealand meat products and it is in this field thai its potential will be tested at Invercargill. but it can also be used to treat fish, vegetables and fruit.

The plant at Invercargill belongs to Dalhoff and King <N.Z.>. Ltd., which is the distributing firm in New Zealand . and Australia for the machine, made in Denmark. Some parts, however, have been made in Britain and Germany, and the unit was a=?embled in Britain before shipment.

The Meat Board has made funds available to the Alliance company for installation

of the unit and experimental purposes and if the unit should prove a success the Southland company has an option to buy it. Installation of the unit has been undertaken by the staff of the Alliance company and. as no experts have come to New Zealand to help, the staff have had to overcome some early problems. Vacuum Chamber

The feature of the unit, which has been set up in a store-room at the works, is the big ball-like vacuum chamber, weighing about four and a half tons, which resembles a diving bell with inspection portholes in its steel dors.

Mr Grant recently explained the general principles of the unit’s operation as members of his staff completed its installation. The meat or other food stuff for dehydration by the plant is frozen to minus 20 degrees Fahrenheit on aluminium travs about 3ft long and 2ft wide, which fit into the machine.

On these trays the meat rests on a layer of metal mesh with another layer on top. , The trays slide into

the vacuum chamber between stainless steel plates, which are opened and closed hydraulically, and held in position by springs. The plates are hollow and water up to 180 degrees Fahrenheit circulates through them. The effect of this is to melt the surface of the frozen meat with the formation of a vapour, which is immediately drawn off. The process takes about eight hours. As the moisture is drawn out of the material and gradually dehydrated, the heat of the water circulating through the plates is also gradually reduced. About 14.000 gallons of water and 30001 b of steam pass through the unit each hour.

The trays are fitted into the machine from entrance doors on either side of the chamber and the unit takes about a ton of material (wet weight) at a time in 60 trays. When the vacuum is broken at the end of the process the latest technique is to flush the machine with nitrogen to inhibit growth of moulds or bacteria in the meat. Packaging Packaging facilities will be located in the storeroom near the accelerated freezedrying unit. It is desirable that packaging should proceed as quickly as possible after the process has been completed as the dehydrated material quickly takes up moisture again.

A package or pouch that is likely to be used comprises a laminated combination of cellophane, aluminium foil and polythene. There is a thin strip of polythene inside so the vacuum pack can be heat-sealed, with an aluminium foil strip in the centre and a cellophane strip on the outside.

The pack is a critical aspect of the whole process as it must be both oxygen and light-proof. If light penetrates the package it will oxidise and break down the fats so bacteria will grow, making the food go bad. The process will not require a big staff. It seems one man will be able to supervise the operation with possibly some help with packaging. The man with the key role at Invercargill

will be Mr W. F. Forbes, who joined the Alliance company three and a half months ago. Born in Tuatapere, he was coal-mining in the Greymouth area for 12 years before shifting to Ohai, in Southland, where he was also coal-mining for about three years and then was engaged in farm contracting for eight years. Mr Forbes has been helping with the installation of the unit. Inquiries An early objective is to produce samples of freezedried products for dispatch to organisations which may be interested in buying them. The Army, the Federation of Mountain Clubs and the Geological Survey have shown some interest in the products. Inquiries have also been received from Australia and Japan. A similar unit is already operating in Japan. Mr Grant does not believe that freeze-dried products can hope to supersede fresh, frozen or even, perhaps, canned products in the higher-living-standard Western countries where people have refrigerators, but he sees a possible field for them in lower-living-standard countries of the East where a pack of a cheap meat product worth, say. 6d or Is. may be used with rice and vegetables. Markets in countries like New Zealand could be limited to meeting the needs of the services, mountaineers and trampers. Mr Grant said that little would be known about cost of production until the plant had been run for a while.