A chilled approach to food processing

10 January 2015

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A chilled approach to food processing

  • Industry Type: Meat, Poultry, Industrial Manufacturing, Food Processing, Cold Storage, Seafood
  • Author: Peter Bullock
  • Service Area: Advice, Design, Engineering
  • Date: 23 May 2012

In the past, the food we ate was determined by the availability of raw ingredients which were lovingly combined to produce wholesome meals that took several hours to prepare in home kitchens across Australia.

Today's time-poor consumer still wants that authenticity – healthy food made with natural fresh ingredients – but they aren't willing to spend the time to create meals from scratch and may even lack the skills to do so.
 
This, combined with advances in food technology, has given rise to a relatively new convenience segment, known as 'fresh chilled'. This encompasses both fully- and semi-prepared chilled and fresh food and drink products that range from smoothies and freshly-pressed juices to ready-to-eat salads and sandwiches, and complete ready meals. The common denomitor with these value-added products is that they haven’t been subjected to high levels of processing, don’t contain preservatives and they require little or no preparation or further cooking.
 
Of course, these products do still need a certain amount of processing, an uninterrupted cold chain, and hygienic and germ-free conditions during the production and packaging to maintain visual appeal and ensure freshness and safety. 
 

Packaging
The development of chilled products has been made possible, at least in part, by new packaging methods that enable them to be sealed in packs to extend shelf life.
 
Modified atmosphere packaging (MAP), an industry standard in Europe, has made its way to Australia and is widely used for sausages and fresh meat, ready meals, sandwiches and fruit salad. The natural air is suctioned out of the space inside the packaging and substituted with a protective gas mix to help the product stay fresh for as long as possible.
 
The protective gas is usually a combination of oxygen, carbon dioxide and nitrogen, individually tailored to the food product. For example, red meat needs a high oxygen environment to maintain their red colour; bread requires low oxygen to avoid mould; and vegetables often need a three-gas mixture.
 
The range of chilled food products suitable for MAP packaging is being regularly expanded as ongoing testing identifies suitability and the correct gas compositions.
 
MAP packaging can be produced using either thermoforming machines or tray sealers. The former are highly efficient and operate at a high cycle time using rolls of plastic film that can be refilled inline with little wastage, while tray sealers work with prefabricated trays. Quality control is paramount to ensure the integrity of each pack and sophisticated gas testing equipment is used, either for random testing offline or automatic online testing of the gas mixture prior to the pack being sealed.
 
The future of MAP is almost certainly linked with the newest technology of high pressure processing that has been developed in Europe and avoids any damage to the packaging materials the integrity of the modified atmosphere. High pressure preservation is done at very high pressure, around 6,000 bars which destroys harmful germs but has little if any effect on the foods texture or taste. Previously this technique has been confined to vacuum packed foods but a new process where pressure build-up and release is done in an autoclave and combined with new MAP packaging concepts will further extend shelf life.
 
The development of this technology will continue apace to create a wider variety of fresh chilled and ready-to-eat food products. It is also important that fresh chilled foods are visually appealing and MAP plays a part in maintaining freshness and providing the best presentation.
 

Keeping it clean
The production of fresh chilled food requires a very clean production environment and near-sterile conditions usually only found in pharmaceutical manufacturing facilities. This means the companies designing and constructing the facilities must have in-depth knowledge of the processes used to ensure the production environment can be easily cleaned and the movement of air can be carefully controlled. For example, floor finishes and wall and ceiling panels must be of the highest quality and interfaces must be sealed to avoid dirt traps.
 
Clean rooms are increasingly being introduced to food processing facilities for the production of fresh chilled foods. Clean rooms are production rooms segregated from primary processing and with their own amenities and more stringent hygiene and clothing rules. Cooked production is often further segregated from fresh production areas. Additionally, other targeted measures to control airborne germs can be used. For example, UV-C modules can be integrated into air conditioning and ventilation systems to irradiate the air channelled into the room and exterminate germs. Air can also be sterilised by atomising special aerosols used in production areas. Active components in these aerosols, such as benzoic acid, lactic acid and hydrogen peroxide, eliminate almost all germs that cause spoilage and can be used even in the production of organic products, but are harmless to humans and don’t damage foods. These systems have been pioneered and installed in Europe and are now available in Australia. Taking such measures ensures the freshness of these fresh chilled foods, however, there are additional facility costs and good facility design is required to ensure the optimum flow for both products and people.
 

Keeping in cool
Controlled-temperature environments are very important for the preparation of fresh, chilled food to ensure the integrity of the product and maximum freshness. To achieve this, increasingly complex refrigeration systems are being incorporated into factories that go far beyond the current chilled and frozen product storage facilities. Production areas are now being designed to operate at temperatures between 4°C and 10°C. This requires factory refrigeration systems with more capacity and adds to the facility design. Production rooms often need to be higher to accommodate the equipment and maximize air flow.
 
Refrigeration is already costly to operate and the upcoming carbon tax will further increase the cost. There are, however, lower energy solutions available, for example, using horizontal air flow in spiral chillers/freezers to maximize the cool air over the largest surface area of the product. This has the result of reducing chilling and freezing times as well as saving energy. Evaporators with large gaps between fins enable increased air flow and minimize excessive frosting so reducing the frequency of defrost cycles and the chilling/freezing times.. This also saves energy as the most energy is used during start up when the system needs to cool from ambient temperature. Facility providers need to understand these factors when designing new facilities or upgrading existing ones.
 

Ramping up robotics
As discussed earlier, MAP packaging is integral to the protection of fresh, chilled food, however, it does not stand alone and must be integrated into the overall production line. With today’s high-volume production lines, robotics are playing an increasing role, automatically loading trays with product prior to the MAP process and then using pick and place robots to load the trays into outer cartons. As a result, robotic palletising is becoming a necessity to match and sustain the higher volume output of these production units. Essentially, if the production time is faster then there is less time for germs and bacteria to spread and the food to spoil before it reaches the consumer.
 
The facilities designed to produce fresh, chilled food, both now and in the future, clearly need to be more complex, more hygienic, and to include much more specialised, advanced equipment.
 
The specific factory design will reflect the process inside them and the requirement for a perfect fit between process and facility will be paramount. The requirement for a simple production space surrounded by four walls and a ceiling is no longer viable.
 
Design and construction of food processing facilities now needs as much knowledge about the process as it does about the building and this gives rise to the need for process engineers to be involved in every facility project. At Wiley, we interweave process and facility using an in-house team of highly skilled process engineers and facility designers.
 
About the author
Peter Bullock is a business development manager at Wiley and can be contacted on 1300 385 988 or connect@wiley.com.au.
 
This article was published in Food & Drink Business Magazine

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