Food Engineering

Australian food technology kept pace with post-war developments not only in materials but in equipment and unit processes as well. In the late thirties spray drying began to replace roller drying in the Australian dairy industry and the latter has now almost disappeared. Newer variations on the retorting of canned foods have already been noted and the proven techniques for the quick freezing of food were brought in. The introduction of fluid bed freezing for peas and fluid bed drying for instant mashed potatoes emphasized the importance to food technology of the fundamental chemical engineering principles of heat, mass and momentum transport, principles which were also applied with success in finding solutions to problems of vacuum concentration. Extrusion technology leading to the rapid growth in the number of snack foods available also is now commonplace.

Reference has already been made to food engineering advances made by the Bread and Sugar Research Institutes; the Australian innovations in equipment for cheese mechanization are discussed later. Membrane technology entered the Australian food industry via a whey utilization project led by L. L. Muller of CSIRO Dairy Research Laboratories. It is a low energy process which has a number of applications in the dairy industry and also in the concentration of fruit juices. As already noted the Australian fruit juice industry is a post-war phenomenon. Quite recently, CSIRO has developed a diffusion extraction process which extracts 98 per cent of the water extractable solids from oranges, thus greatly increasing the yield though the product is not juice as defined. The equipment, which has been developed on the counter current principle, may be used for a number of related purposes.

Throughout this review there are references to the Australian manufacture over some 150 years of equipment for various branches of the food industry. Much has duplicated what has been available overseas but much also has been, and continues to be, innovative. Also, from Ritchie (pp. 81-82) onwards, engineers in the Australia food industry have made clever modifications to imported packaging machines, often significantly increasing the rate of throughput, or have themselves made innovations in materials handling or packaging equipment, sometimes on processing lines, sometimes on filling lines. Some are well known, some have already been referred to and some remain unpublicized.[177]

Reference has already been made to the importance of cleaning and sanitation in the food industry and the development overseas of systems for cleaning food processing plants without dismantling them, cleaning-in-place or CIP, was enthusiastically welcomed in Australia in the 1960s. Some local food engineers showed considerable ingenuity in designing for their own purposes new systems built up from available unit equipment. A lot of this was shared in conferences but much remains unpublished, often because those responsible consider what has been done to be unremarkable. CIP may, however, be a two edged weapon. It is not fool proof and unless checked regularly by a microbiologist unsuspected contamination may build up.

Australian Academy of Technological Sciences and Engineering