Chilled food market hots up

Consumers love the convenience of freshly made, freshly processed and freshly cooled product, and this is driving huge growth in the chilled food sector.

In addition to complete ready meals, this segment primarily encompasses fresh pizza and pasta that only need to be baked or cooked, as well as kitchen-ready cleaned vegetables and salad preparations or complete, ready-to-eat salads to which only dressing needs to be added. Other examples of chilled food include sandwiches, cut and portioned fruit and even plates of sushi. Chilled beverage products include smoothies and freshly pressed juices. What all of these products have in common is that they aren’t preserved thermally and don’t contain preservatives. They are all sold in a chilled state and can be eaten after only minimal preparation.

Chilled products enable food companies to create more value than is the case with conventional ready meals or refrigerated products. They also offer consumers the opportunity to enjoy freshly prepared food without needing special skills or having to spend much time preparing meals. However, these miraculously fresh products do require a certain amount of processing. In addition to needing an effectively uninterrupted cold chain, hygienic and germ-free conditions are needed during the production and packaging of chilled food.

The focus is therefore on the microbial count of the raw materials, packaging materials, processing areas and finished products.

Clean surroundings are essential

A clean and nearly germ-free production environment is the primary precondition for ensuring that preservatives and heat treatment are not needed to manufacture refrigerated fresh products.

In addition to strict hygiene on the part of personnel and the regular cleaning of all surfaces, machines and operating materials, such an environment can best be attained through the use of an appropriate air management system. As a result, clean rooms are slowly being increasingly used in food production.

However, targeted measures can also be employed to ensure that airborne germs do not get anywhere near chilled food in normal production facilities. For example, UV-C modules can be integrated into air-conditioning and ventilation systems. These modules irradiate the air channelled into the room so that airborne germs are effectively exterminated.

Air is also effectively sterilised by atomising special aerosols in the production areas. The effective components of these aerosols are substances such as benzoic acid, lactic acid or hydrogen peroxide. These substances can even be used for the production of organic products and they also are effective on the food’s surface. Although they eliminate almost all of the germs that cause spoilage, they are harmless for human beings and do not damage the product.

Everything is under control in the packaging as well

Chilled food can be shrink-wrapped, which is particularly suited for pasta and fully prepared meals. By contrast, sandwiches, sushi and salad preparations would be damaged by such packaging or lose their fresh appearance. That’s why modified atmosphere packaging (MAP) on trays is frequently used for such products. MAPs replace preservatives with a germ-free gas atmosphere that is tailored to the food in question in order to keep cut fruit, salads and vegetables fresh. But tray packaging is also useful for other applications. The merger of freshness and convenience is made perfect by all-new plastic wrapping that allows kitchen-ready chilled products to be cooked or baked in the microwave directly on the tray.

Creating clean conditions with high pressure

High pressure preservation (HPP), a non-thermal method for preserving food, has recently become generally available. This method reduces the number of undesirable microorganisms in food in a manner that preserves the product’s properties. HPP helps to meet the increasing demand for very high quality food products lacking additives.

High pressure preservation of food is generally performed at a pressure of up to 6000 bars, which destroys any harmful microorganisms that the products may contain. The high-pressure treatment is employed on primary packaged food. The process causes negligible thermal stress and hardly changes the food’s structure, its taste or the valuable nutrients it contains.

Protective gas packaging that is especially adapted to high pressures is used as the primary packaging to ensure that product quality remains unchanged during the food’s shelf life.