Hygienic design

To produce food under assured hygienic conditions, production machines and processes must be designed in line with hygiene-oriented standards.

Consumers don't want to find microorganisms or residues of cleaning agents or machine lubricants in their yoghurt, meat or bread rolls. However, there is no such thing as 100% food safety. “On the one hand, this isn't even theoretically possible, and on the other, food production in practice is much too complex,” says Professor Herbert J Buckenhüskes, head of the Food Technology department of the German Agricultural Society (DLG).

To fulfil today’s wide-ranging hygienic requirements, food processing equipment must feature good cleanability and the avoidance of dead spaces and corners that are inaccessible or hard to reach where food residues can be trapped. The choice of materials for the surfaces that the food in the machine comes into direct contact with is important as is the lubricants that are used for the machine.

Analytics, materials science, process technology and computer simulation can be used to optimise hygienic conditions and, at the same time, boost the cost-effectiveness of the production process.

Stainless steel is the hygienic material of choice for the food industry. But even stainless steel rusts under certain conditions; for example, if it comes into contact with chlorides in the process water, cleaning materials and disinfectants or acidic foods. The rusting, in turn, makes it more difficult to clean the material. Furthermore, the rust can also contaminate the food.

In order to solve this problem, it's not enough merely to use highly stable stainless steel alloys in certain situations. In addition, metal surfaces can be subjected to special treatment such as electropolishing. This reduces the roughness of the metal surface so that it offers microorganisms less surface area to hold on to. In addition, this process removes oil and fat from the metal surface. As Professor Buckenhüskes points out, "This is an expensive process, but it has long been common practice in the pharmaceuticals and biotechnology sectors."

But in the food industry as well, the trend is clearly towards higher safety. "Ultimately, no food manufacturer can afford to have a recall campaign," adds the DLG expert.

"Hygiene-improving measures can reduce the amount of time and chemicals that are needed to clean machines. This offers food producers a lot of potential for reducing their costs. As a result, the basic principles of hygienic design can be implemented at no additional cost, or even at a profit," says Professor Buckenhüskes. And that's no surprise, as cleaning processes account for up to 40% of changeover time in the food industry.

In order to further automate and optimise cleaning processes, the food industry is working to develop special hygiene sensors to determine when and how much cleaning is required and identify any cleaning product residues. New methods are also being used to design cleaning products. The old rule of thumb, ‘The more, the better’, is now a thing of the past, and in individual cases it has even proved to be counterproductive. Today, we know that the key to success is the interaction of the right choice of cleaning products and processes and the materials used.

Another reason why food producers are interested in optimising their cleaning processes is to minimise the need for including allergen risks on their labels. One problem in this area is the allergens in food, ie, food residues originating in previous production processes. Such cross-contamination has to be avoided. That's why machines and plants in critical areas such as the manufacture of gluten-free foods are sometimes used only for one particular purpose. "However, for most food manufacturers this is not worthwhile over the long run," says the DLG expert.

Upstream and downstream production machines must also fulfil hygienic requirements. But it's not only the core machines in food production that must fulfil hygienic requirements; in principle, these requirements apply to the entire process chain. That refers to packaging machines as well as automation units and the open conveyor belts on which food products are transported.

Human beings also remain a critical factor in the food production process. "Supervisors can't always stand next to the workers and make sure that the hygiene regulations are being complied with," explains Professor Buckenhüskes. "It's a lot harder to monitor people than machines." For this reason, the issue of hygiene is also reinforcing the trend towards increased automation in the food industry. In particular, manufacturers are increasingly using robots.

The supporting program at Anuga FoodTec will be devoted to the topic of 'Hygienic Design'. The special show 'Robotic Pack Line', initiated by the German Agricultural Society (DLG) Koelnmesse and partners from the technology sector, will demonstrate safe, quick and hygienic methods for producing, processing and packaging food products — all without human aid, since the system is fully automated. In addition, the European Hygienic Equipment & Design Group (EHEDG) will focus on the topics 'Fresh Produce' and 'Aseptic Packaging' in the Anuga FoodTec Forums. Anuga FoodTec is jointly organised by Koelnmesse GmbH and the DLG. It will be held from 10 to 13 March 2009 in Halls 4 through 10 of the Cologne exhibition centre.