Cleanroom technology ensures longer-lasting produce

What do space ships and soft drinks have in common? No, it’s not a corny joke. Both use cleanroom technology - a technology that started life as an aid to space flight and is now used in a number of other industries.

Current consumer demand is for fresh food products but also, paradoxically, for foods that keep for longer. In response to this, cleanroom technology is changing to ensure hygienic preparation and processing of food products to allow foods to be stored for longer without spoiling. By preparing and packaging foods in germ-free conditions, products can keep for up to 50% longer.

The evolving room

Industrial cleanrooms were first developed in the 1960s to create extremely clean conditions for manufacturing microelectronic circuitry for spacecraft. Today, all microchips are manufactured in environments with low particle counts. Cleanrooms are now used in electronics, pharmaceutical, medical, manufacturing and food processing industries.

Although cleanrooms differ widely, they are always constructed on the same principle. The cleanroom is accessed by passing through a ‘grey area’ and then air locks, while the cleanroom itself is controlled by airflow systems and air filters that trap small particles and microorganisms. Using special high-efficiency particulate air (HEPA) filters, the systems filter out particles larger than 0.5 µm in diameter, which means that bacterium (with an average diameter of 2 µm) are excluded from the room.

Requirements for particle counts differ between applications, with requirements defined by ISO classes. A Class 5 room, for instance, would permit no more than 3520 particles/m³, with each particle measuring no more than 0.5 µm in diameter - equivalent to 3.5 particles/L. In contrast, air in a typical urban environment contains 35 million particles/m³, with particles 0.5 µm and larger. A Class 9 cleanroom has a comparable particle count to an urban environment.

Dust particles don’t represent too great a threat to food production - as long as they aren’t attached to germs - so the food industry generally only requires cleanrooms of ISO classes 5, 6, 7 or 8.

Small is beautiful

Large cleanrooms can be expensive to set up and maintain, so there has been a trend towards smaller cleanrooms in the food industry where practical. The risk of contamination is proportional to the size of the cleanroom, so smaller can often be better. More food processors are installing ‘mini environments’ or ‘flow boxes’ - small, enclosed cleanroom units - for processing plants. Some are even transportable.

Some beverage-bottling manufacturers have embraced the small cleanroom concept with a technique called aseptic cold bottling, which involves cold bottling in a sterile environment, as a way to ensure sensitive, non-carbonated beverages have longer fridge life without the need for added preservatives or thermal stress.

In aseptic cold bottling, only the path the sanitised bottles follow through the insulator and the filling and sealing machines are ISO 5 cleanroom spaces, significantly reducing the cleanroom space required in a beverage plant. In fact, many modern bottling plants require only 10% of the cleanroom space of older plants.

Many aseptic bottling plants feature a Class 6 room installed within the Class 5 section to ensure recontamination does not occur. These room-in-room designs are not only cheaper to install, they may also guarantee a higher hygiene level than large cleanroom constructions.

Cleanrooms for less perishable food products

Using cleanrooms in food processing has a number of benefits. Removing germs from the production and packaging processes ensures not only greater food safety but also improves the product’s longevity. Contamination by germs can cause a drop in the quality of a food product, or even premature spoilage, but refrigerated goods produced and packaged in cleanrooms keep longer than those that are not.

Food that is processed in cleanrooms can also be transported and stored for longer, potentially opening up new markets for producers.

As consumers continue to seek out fresh produce that keeps for longer, it seems that cleanroom technology will increasingly become a desirable way for food processors to keep ahead of the pack.