Food processors shine with stainless steel motors

Attitudes to food hygiene are changing markedly as the supply chains lengthen – often to global proportions. With ever more plant and machinery used in food production, storage, processing and logistics, OEM engineers are looking to design-in cleanliness. Motor expert Bill Bertram of Marathon Electric Motors explores the issues.
 
Bacteria thrive in wet, warm atmospheres, conditions often found in food processing factories, storage and logistic facilities and farmers’ harvesting, grading and cleaning equipment.
 
Not surprisingly then, cleanliness and hygiene are high on the agenda for companies in the food chain. (The top of the food chain is often a giant supermarket group, whose buying power is such that they can demand high levels of sanitation right down the line.)
 
Engineers designing machinery for use in food environments are increasingly turning to materials such as stainless steel, aluminium, ceramics and high performance plastics, which are easily cleaned, don’t rust or corrode, and can withstand cleaning fluids and steam cleaning. They are also developing clean-lined designs without nooks, crannies, grooves, furrows, etc., where bacterial growth can gain a foothold and remain unseen.
 
Naturally the OEMs need to bring their suppliers into the fold, so ask them to develop components that meet the cleanliness objectives. For instance, Marathon Electric Motors has developed ranges of food industry motors, which, in brief, are clean-lined so that there are no crevices where bacterial build-up can start and are steam and/or waterproof for cleaning-in-place and other demanding washdown regimes. The Marathon motors are made of stainless steel so that there is no need for paint that could flake into the food, hold in moisture and hide corrosion. The motors are of TENV design, which means that they do not have a fan and fan cover, which are both difficult to clean and could be the breeding space for bacteria.
 
This design has just one shaft end (at DE) which reduces the danger of water penetration to the inside of the electric motor alongside the shaft end by half.
 
Each motor is equipped with 3off Drain Holes, which come plugged with solid stainless steel screws. A Capillary Drain Plug is supplied loose with each motor (inside the Terminal Box in plastic bag) so depending on the mounting position the user can decide whether to use it or not. The Capillary Drain Plug must be fitted to the lowest point (lowest drain hole).
 
In cases where motors are installed in vertical position with shaft up and the flange is subject to flooding, the cleaning water needs to be drained off. The stainless steel grub screw plug at the side of the DE Endshield needs to be permanently removed to open the drain canal.
 
Furthermore, food industry motors typically use sealed-for-life bearings to support the output shaft, so that there is an absolutely minimal chance of lubrication contaminating the food. The other seals in the motor have been redesigned so that there are no grease plugs where dirt can collect, while mounting arrangements do not create grooves and crevices. The terminal box located at NDE is designed to be totally waterproof, even under pressure washing, and not to have nooks and crannies.
 
Food contamination can be an expensive business including lost output, lost production time, product recalls, lost reputations, etc. Social research suggests that somewhere between one-in-ten and one-in-five people in North America and Europe suffer a food-borne illness each year, which could lead to discomfort, time off work, hospitalisation, long-term effects or even death, particularly in the young, the elderly and the vulnerable.
 
It is not surprising that hygiene regulations in relation to food handling are being tightened around the world. In America, for instance, the Food and Drug Administration is strengthening the scientific research that will ensure bacterial safety as the food supply network becomes wider and more complex. The new Food Safety Modernisation Act (2011) for example is designed to prevent contamination in the food chain, rather than define reactive procedures for dealing with problems, once they arise.
 
Further, food manufacturers are now required to prepare formal plans for preventing contamination from entering their facilities, and to prevent their facilities from passing contamination up the supply chain. Growers, packers, storage operations and transport operators are also being subjected to stricter regulation, and regulations apply to machinery, personnel and operating procedures.
 
Similar regulations are being introduced in Europe and around the world. China, with its rapidly urbanising population, is developing major food factories and strict hygiene regulations at an unprecedented rate. Elsewhere in Asia, the culture of street food is coming under scrutiny, while Africa and India are developing practises to meet the requirements of their western customers.
 
Consumer trends also have to be assessed and future developments forecast, so that legislation can be ‘future-proofed’ and remain relevant over the coming years. For instance, as countries become more developed and lifestyles become busier, there is an increase in demand for the convenience of ready-to-eat food and partially processed items that do not need so much time-consuming preparation in the kitchen at home. There is also a growing desire for ‘exotic’ foods, which leads to longer supply chains. Finally, there is always pressure for food companies to maintain and improve their profitability, which could squeeze hygiene practices if left unchecked.
 
While plant and machinery is only part of the issue of hygiene in food production, and motors are only part of the machinery, it is notable that responsible motor manufacturers have been proactive in the need to develop hygienic motors. While development costs have been high, the motor makers are able to spread these over a wide area, because such motors are also suitable for pharmaceuticals manufacture, biotech plants, electronics production, medical uses and satellite-building facilities. Further, there is also a trend for them to be used in locations where the public are likely to see equipment, such as at theme parks and in retail displays, again helping to spread the costs.

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