Minimising contamination risks through hygienic design

Legislation is partly to blame. For example, before the arrival of the General Food Law Regulation (EC 178/2002), companies were able to make judgement calls about whether they needed to withdraw a product on safety grounds. Now they only have to have a concern and they’re forced to act.

Some of the most high-profile product recall cases have been the result of contaminated ingredients, such as the £100m recall of half a million Cadbury’s bars thought to have been contaminated with salmonella in 2006. Others are to do with labelling, especially where manufacturers have failed to warn consumers about the possible presence of EU-listed allergens.

But there is a third group of incidents, in which contamination arises from within a manufacturer’s process. These often attract less publicity than other problems, but they are probably the most common cause of recall incidents for food businesses.

Combined with today’s emphasis on hazard analysis, risk assessment and prevention, the growing cost of product recall means that the importance of investing in hygienic design has never been greater. By choosing equipment that has been designed from the bottom up for hygienic applications, manufacturers can make life a lot easier in the long run. Not only does the right equipment help minimise the risk of product recall incidents, it can also help solve day-to-day production headaches, such as simplifying clean-down procedures, for example.

While it may seem obvious that major process items such as specialised reaction vessels should be designed with hygiene in mind, it’s often the peripheral equipment that makes the biggest difference. Where flowmeters are concerned, producers of food, beverage and pharmaceutical goods should only really be considering dedicated hygienic designs for their processes.

Introducing the HygienicMaster flowmeter
A case in point is ABB’s own HygienicMaster range of flowmeters, certified for hygienic duty by both the FDA and EHEDG. The recently launched, HygienicMaster is a great example of how the sort of standard equipment used in virtually every industrial process can be successfully redesigned specifically to prevent contamination.

A key consideration in the development of the product was the elimination of any points of potential contamination.

A stainless steel construction and gasket-free sensor design eliminates crevices where bacteria might otherwise get a foothold. Electromagnetic meters rely on electrodes, which could break up the smooth internal profile, so the HygienicMaster electrodes are embedded in a smooth, gap-free reinforced PFA liner. A large selection of electrode materials, electrode shape and connections makes the meter suitable for any process.

The PFA liner is also impervious to thermal shock, which is in marked contrast to the ceramic liners sometimes offered by other hygienic meters. If a sudden change in temperature causes cracks in a ceramic liner, it also opens up the possibility of the liner fragmenting and actually contaminating the product itself. Although PFA liners traditionally posed a problem for flowmeter producers in the past, developments in the technology and bonding arrangements have made it the first choice for food, beverage and pharmaceutical applications. The improved tolerance to temperature stress, have increasingly widened the scope for its use.

As a further measure against contamination, the overall internal shape of the meters is designed to be self-draining, so no residual pools of moisture can build up and affect the product. This is especially important in food operations, where production lines are often multi-purpose and cross-contamination between product runs is a potential risk.

Maintaining hygienic integrity
Of course, good housekeeping has an enormous role to play in maintaining hygienic conditions. Even a great design could be compromised by poor fitting or damage to the equipment. For this reason, the HygienicMaster flowmeters include a number of features designed to make the integrity of their hygienic status as fool-proof as possible.

For example, the flowmeter can be supplied with a ‘jig fixing’, which enables users to weld the meter to the pipe without damaging the meter or compromising its hygienic design.

Similarly, ‘through the glass’ technology enables the operator to program the device without having to open up and expose the transmitter electronics. This avoids the possibility of the ingress of dirt, contaminants or moisture. Removing the need to open up the transmitter in this way also helps prevent a situation where any components taken out of the transmitter, such as a rubber gasket or a screw, for example, could find their way into the food product. The meter also has infra red service port technology, which means it can be read through the glass. In addition, the introduction of a Gore-Tex membrane in the transmitter/sensor electronics prevents moisture from building up in particularly humid environments.

The meter’s NAMUR NE107 self-diagnostic capability makes it easier to maintain and ensures that any problems are drawn immediately and clearly to the attention of the operator. Alarms and warnings are given status classifications, such as ‘maintenance required’, ‘function check’, ‘failure’ and ‘outside of specification’. This means that even in the case of something going wrong, it should be easy to pinpoint any product that may have been damaged, thereby minimising reject costs.

Making operation easier
Of course, even the best designed product can be compromised by an operator error. Many process operators in food or pharmaceutical industry factories who only occasionally operate and parameterise their measurement instruments share the same problem: the increasing number of instrument functions often leads to more and more complex menu structures. This is aggravated by the almost unmanageable multitude of devices in cases where plants comprise package units from different plant manufacturers, with each unit comprising instruments from different manufacturers.

In making the HygienicMaster as simple as possible to operate without compromising the instrument’s capabilities, ABB’s design team adopted many of the same principles pioneered by mobile phone manufacturers. Despite the rapid leaps forward in mobile phone technology and functionality, mobile phone handsets have become easier to operate and navigate around, providing users with quick access to a wealth of applications.

The HygienicMaster therefore features softkeys which, when operated, trigger an action that is related to the situation and that is indicated in the display.

Simplified commissioning and maintenance
For operators, this simplified approach provides a raft of benefits, not least in terms of simplified commissioning and maintenance. The need to program instruments of differing complexities from different manufacturers can often cause problems to service technicians, who are forced to read manuals before being able to customise replacement devices to local process parameters and operating conditions.

In the HygienicMaster, this hurdle is overcome both by a simplified Windows™ interface and by the instrument’s parameters being stored in both the sensor and in the converter. In case one of the units has to be replaced, the new converter accepts the process parameters from the sensor, or the existing converter transfers the data to a new sensor.

Summary
Everyone in the industry wants to make safe food and drinks. Even so, legislators and retailers are continuing to demand ever-higher standards of control. Good, hygienic design is therefore essential throughout food production facilities, and it pays for manufacturers to look for equipment that has been developed specifically with their particular needs in mind.