Dressing up for dinner

Cleanrooms as we know them evolved from the American Space programme in the 1960s. This was also the period when NASA and the Pilsbury Company, in conjunction with the US army laboratories, developed HACCP (Hazard Analysis Critical Control Points), their aim being to ensure the microbiological safety of food on the early 1960s space projects.

Then it was pharmaceutical companies (and later semiconductor manufacturers) who adopted cleanrooms for an advanced level of product protection. The food industry largely focused on visible contaminants such as human hairs, although it was also concerned about controlling bacteria. In many ways food and pharma diverged, although the theory and practices remained common – both needed to control visible and non-visible contamination.

Where pharmaceutical and semi-conductor companies constructed cleanrooms, food manufacturers tended to follow practices resulting in better hygiene but without the need for the filtered air that cleanrooms provided. As food production has become more complex and with the introduction of ready meals and chilled foods, the need for stricter controls has grown. Traditional cooking methods have always been used to kill harmful bacteria but modern “convenience” meals are not necessarily designed for that and so have to be produced under the most hygienic conditions. Reductions in salt levels and preservatives pose an increased threat as food becomes more hospitable to bacteria.

HACCP practices and directives from the EU, together with various food hygiene and safety regulations, have led to a vast improvement in food production over recent years and the 2006 legislation relates to greater microbial control. Prevention rather than cure is always the best approach and this strategy reduces the risk of heavy fines and loss of business.

In many cases it is virtually impossible to produce “totally safe” food, so the best possible solution is to minimise risks at every stage. It is at this point that cleanrooms and food manufacturing converge again. Aseptic processing may seem appealing, but is not possible for all food types, and the high cost imposes limitations. Irradiated food is a possibility but is seen as undesirable by many consumers.

The risk to food can come from a number of sources that will vary by food type and the production environment. Although humidity levels and moisture are a major concern, the greatest risk still comes from the human element, either from inadvertent contamination or by error. HACCP-recognised hazards (physical, chemical and microbiological) are usually well understood, but further improvements can be made. Despite cases of food-borne illnesses declining over the past decade, the numbers are still alarmingly high and the solution to minimising the risks will vary from one food type to another – although poor discipline remains one of the greatest attributing factors to such illnesses.

Garment selection

As humans contribute around 80% of harmful particulate in a controlled environment (see figure 1), it is essential that an understanding of how an item of correctly worn apparel can drastically reduce that level. The type of garment and how it is worn are a critical part of the garment selection process. The garment has to be comfortable for the wearer, but its primary role is to act as a filter that will ultimately protect the surrounding manufacturing process. Additional consideration should be given to the quality and standard of the wash process, ensuring segregation of garments used in raw food production and potential allergenic carriers, such as nut production.

Traditional polyester/cotton garments not only have design limitations but also add contamination due to their high linting characteristics and, contrary to popular belief, they become less comfortable to wear as body heat and moisture will cause the cotton structure to swell and block breathability. Modern cleanroom polyester garments are a cost-effective solution due to their longevity and their improved levels of cleanliness, filtration efficiency and comfort, plus many have design features which enhance these factors further.

Managing human behaviour is essential in any workplace, but food production areas have to rank among the most critical. Wearing a protective garment will not solve the problem alone as not only does it have to be worn correctly, but the correct selection of type and style has to be made in the first instance. Figure 2 shows 0.5µm particle levels in a change room (room empty) compared with an operator wearing four different garment types; it illustrates the scale of particle reduction when using a polyester coverall. It is worth noting that this study was conducted with the wearer undertaking slight upper body movements; these figures would increase substantially if walking across the controlled environment.

Operators can contribute around 80% of all contamination in a production area, but the use of certain styles of apparel can reduce hair and fibre contamination by at least 75%. A human hair in food will appear undesirable, but it is what we cannot see that can pose the highest risk at a microbial level. Again the selection of garments with the addition of gloves will minimise risks substantially. Hand washing is a natural requirement, but the wrist area will contribute more bacteria than the hand, hence the need for longer gloves and possibly cuff sealing methods at the wrist. Cross contamination when donning the gloves and garments should be another concern; if the apparel has been contaminated during the donning process, e.g. from associated packaging materials, then it becomes a potential problem itself. Hand sanitisation and garment training, essential in cleanrooms, is an equally important consideration for food handlers.

The disinfection of floors and equipment is common practice in food production areas, but airborne micro-organisms are becoming more of a concern to food manufacturers and regulatory bodies. HEPA filters used in cleanrooms are an effective method of controlling this risk. A cleanroom constructed to a pharmaceutical standard will have associated higher costs, although food companies that have adopted them have found that the shelf life of products has been extended. They have also enabled preservative levels to be reduced.

The culture of food production is slowly seeing a paradigm shift beyond typical HACCP, but to undertake true cleanroom protocols will not occur overnight. In the interim, a structured approach to minimising the risks should be taken and the biggest risk usually comes from people. The selection of the correct apparel and associated training is the best means of reducing risk while increasing profit.