Cleanrooms in the food industry: why and for whom should a controlled-atmosphere zone be implemented?

A cleanroom in the food industry is a production area where air quality, temperature and airflows are strictly controlled to minimise product contamination. Indeed, in addition to standard good hygiene practices, certain sensitive products require an environment where airborne particles are strictly controlled. However, not all production processes require one: a cleanroom must meet specific requirements, and its cost and complexity must be justified by the type of product being manufactured.

This guide explains what a cleanroom in the food industry is, for whom it is relevant, its technical requirements and how the choice of equipment contributes to this.

What is a cleanroom in the food industry?

A cleanroom in the food industry is a controlled environment where the concentration of airborne particles is monitored and maintained below a defined threshold. Indeed, according to the ISO 14644-1:2015 standard, a cleanroom is classified according to the maximum concentration of particles per cubic metre, ranging from ISO Class 1 (the cleanest) to ISO Class 9 (the least stringent). Thus, the lower the class, the cleaner the air and the higher the technical requirements.

In practical terms, a cleanroom goes far beyond a simple area with enhanced hygiene standards. A conventional hygiene zone relies on cleaning, disinfection and one-way traffic, but it does not actively control airborne particles. In contrast, a cleanroom controls airborne contamination through air filtration, positive pressure and airflow control.

Cleanrooms, grey rooms and ZACs: the nuances

Not all production processes require a full cleanroom. Indeed, when the requirements do not justify the strictest level, an intermediate solution exists:

• Cleanroom: active particle control in accordance with ISO 14644 classes, HEPA filtration, positive pressure, controlled airflow.
• Grey room (or ZAC): an intermediate level of control, simpler and more cost-effective, between a cleanroom and a standard hygiene zone.
• Enhanced hygiene zone: cleaning, disinfection and forward flow, without active air control.

Furthermore, for the control of biocontamination in cleanrooms, the EN 17141 standard provides a reference framework that complements ISO 14644.

For whom is a cleanroom in the food industry relevant?

The cleanroom in the food industry is not a universal standard. In practice, it applies to specific production scenarios where controlling airborne contamination delivers real value.

Products with a long shelf life

Products designed to have a long shelf life without preservatives benefit directly from a low-contamination environment. Reducing the initial microbial load at the time of packaging automatically extends the product’s shelf life. As such, chilled ready meals, fresh dairy products and seafood are often concerned.

Clean label initiatives

Reducing or eliminating preservatives requires compensating for this through strict control of the production environment. Consequently, the cleanroom is a technical tool for delivering on a clean label promise: the product is preserved thanks to the cleanliness of the process, not through the use of additives.

Exporting to demanding markets

Certain export markets impose strict specifications regarding the production environment. Consequently, having a qualified cleanroom may be a prerequisite for accessing these markets, particularly for high value-added processed products.

Managing multiple allergens at a single site

When a site manufactures several products containing different allergens, controlling material flows and air movement helps to limit cross-contamination. Thus, physical separation and atmosphere control contribute to food safety and labelling compliance.

The technical requirements for a cleanroom in the food industry

Building and operating a cleanroom in the food industry relies on several technical pillars. In practice, these requirements work together to maintain the target cleanliness level.

Air filtration

This first pillar is at the heart of the system. HEPA filters offer an efficiency of at least 99.99 per cent at 0.3 µm, whilst ULPA filters achieve 99.9995 per cent at 0.12 µm for the most demanding environments. As a result, the air is frequently renewed and stripped of particles before entering the clean area.

Positive pressure and pressure cascade

The cleanroom is then maintained at a positive pressure relative to adjacent areas. As a result, air flows from the cleanest area to the least clean, preventing contaminants from entering through doors or gaps. Furthermore, this pressure gradient is a parameter that is continuously monitored.

Non-porous and washable materials

The surfaces in a cleanroom must be smooth, non-porous and easy to clean. This is because porous materials trap residues and encourage microbial growth. This is why equipment and tools that come into contact with food must also have non-porous and washable surfaces, such as food-grade platinum-cured silicone.

Control of personnel and material flows

Finally, access to the cleanroom is regulated by changing rooms and strict procedures. Staff enter via a changing room wearing dedicated clothing, whilst materials follow a controlled route. This separation of clean and dirty flows is a principle shared with the ‘forward flow’ system used in industrial bakeries and food production in general.

ISO classes vs production types: the summary table

Here is a summary of the ISO 14644-1 classes and their typical uses, to help determine the appropriate level of cleanliness for each production process.

Choosing cleanroom equipment: why it matters

In a cleanroom in the food industry, all equipment in contact with the product must meet the same standards as the environment itself. Indeed, equipment that is porous, inadequately certified or difficult to clean directly compromises contamination control. This is why the choice of production moulds is a key consideration. At Maé Innovation, two ranges meet these requirements: Silmaé, made from platinum-cured silicone, and Fibermaé, made from silicone-coated fibreglass.

Silmaé: platinum-cured silicone, with a non-porous, easy-to-clean surface

Silmaé moulds are made from food-grade platinum-cured silicone, whose smooth, non-porous surface minimises residue retention and facilitates cleaning. They therefore meet the cleaning requirements of a controlled environment. Furthermore, their natural non-stick properties eliminate the need for greasing, a potential source of additional contamination.

Fibermaé: silicone-coated fibreglass for high-stress applications

For applications requiring rigidity and high-temperature resistance, the Fibermaé range, made from silicone-coated fibreglass, withstands temperatures up to +300°C. Indeed, its rigidity makes it suitable for automated production lines and high-volume production. Furthermore, like Silmaé, it is certified for food contact in both the EU and the US.

Visual differentiation by colour

Maé Innovation’s Silmaé moulds are available in several colours. In practical terms, this visual differentiation allows a specific colour to be assigned to a particular use, product or area, thereby minimising the risk of cross-contamination, particularly at sites handling multiple allergens. Furthermore, this colour-coded system fits well within a rigorous quality management approach.

FAQ: