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Meeting the challenge of keeping ambient temperatures cool

1st April 2013


Although regulations are in place to ensure that food materials remain cool, operations such as handling during preparation, transport and storage can all lead to temperature rises and the risk of contamination. Richard Mercer outlines the current legislation and shows how a new, rapid cooling system can benefit the whole industry.

Food processing plants, packaging warehouses and storage areas vary significantly ­ from product to product and company to company. Dairy processing plants differ from meat manufacturing plants, dried food packaging factories differ from those that pack vegetables, and the storage conditions for cooked foods differ from the storage areas for chilled and frozen products.

These differing environments, from process through to purchase, are, on the whole, regulated by legislation.

However, this legislation can only go so far in ensuring that foods are protected from spoilage. In the US, for example, it tends to be the norm that, because of the wide temperature differences (heat through cold), all food movement, whether in buildings or in trucks, is carried out in air-conditioned environments. In Europe, however, this is not yet fully the norm, although more frequent than it used to be.

Instant temperature reductions

Food industry professionals should ensure that they have their own measures in place, which complement the regulations.

For instance, during very hot summers, when foods are being handling and stored (even if temporarily), in particularly warm temperatures, high-powered cooling systems can provide instant reductions in temperature, thereby slowing the growth of pathogenic microorganisms and toxins.

Clearly, cooling systems are not appropriate for all foods. Canned and dried products are designed to last long periods in ambient temperatures, and foods that require hot holding should be stored and handled in sufficiently high temperatures.

However, foods such as fresh produce, fruits and vegetables would certainly benefit from powerful systems when no other cooling and chill holding systems are in place.

Current legislation

There are numerous regulations and guidelines that address food standards. For instance, the Codex Alimentarius Commission provides recommendations on the transport and storage of foods, and the International Standards Organisation lay down quality assurance standards for food produce.

However, it is the legislation implemented by the European Union Food Hygiene Directive (93/43/EEC), which covers food temperature controls in most depth, and which is most readily incorporated into the food laws of individual European countries.

In the UK, for example, the Food Safety (temperature control) laws (1995-2002), which incorporate the European food regulations, state that no foods requiring chilled storage should be kept at temperatures above 8oC. They also lay down the following requirements: p No person, in the course of a food business, shall keep foodstuffs, which are raw materials, ingredients, intermediate products or finished products and likely to support the growth of pathogenic microorganisms or the formation of toxins, at temperatures which would result in a risk to health.

This may require foods to be held at specific temperatures below 8oC. However, consistent with food safety, limited periods outside temperature control are permitted where necessary (for practicalities such as handling during preparation, transport and storage).

Although these regulations implement comprehensive temperature controls for foods in general, they have limited scope for controlling the temperatures of all foods during every link in the process to purchase chain.

How does warmth effect food?

According to the Institute of Food Science and Technology, pathogens can contaminate food, and some multiply at an enormous rate if given favourably warm conditions. Therefore, to keep foods safe, there needs to be measures to prevent contamination, multiplication and survival (see www.ifst.org).

With each 10oC rise in temperature, the activity of microorganisms and enzymes increases by at least two times in the range 0-60oC. Therefore, when foods are kept at ambient temperatures, even for very short periods of time, microorganisms are being presented with the perfect conditions for rapid multiplication.

Chilled and frozen foods are especially vulnerable to increases in temperature, as acknowledged by the Australian Food Authority: "Breaks at critical points in the cold chain can result in food that is likely to cause food poisoning and/or irreversible damage to the quality of the product. Chilled foods, particularly, are more vulnerable to microorganism spoilage through temperature variations, which can cause reduced shelf life“. For more see www.afgc.org.au.

How to reduce risk

As cooling reduces the rate at which pathogenic microorganisms and toxins grow, ambient storage and handling conditions should be avoided. When outside temperature regulations (for reasons of practicality), foods should be kept in cooled surroundings in order to minimalise deterioration.

The Australian Food Authority has identified the need for temperatures to remain at a constant for each link from manufacturer to consumer by implementing a anever warmer than rule' in its guidelines (2000). This specifies that products must be stored and handled never warmer than a particular temperature, thereby ensuring the food's continuous safety and quality.

This never warmer than rule can be used as a precedent for European food companies' own temperature controls, especially now that Hazard Analysis Critical Control Points (HACCP) is becoming an increasingly popular system, propitiated by the European Union. This system allows the food industry to identify points in the production line where food is most likely to become contaminated, and to provide controls accordingly.

A new solution

The Patterson Ice Cube (Fig. 1), which is currently being launched in the UK, can reduce ambient temperatures by up to 20oF. With the capacity to cool areas up to 1500ft2, it represents a possible solution to the food industry's problem of keeping foods in a cool environment, especially when outside the temperature controls set in legislative guidelines. The Ice Cube may also prove helpful as short-term, or emergency back-up in case of system breakdown.

With its easy to roll, locking caster, and UV protection plastic casing, the air-cooling unit can be conveniently rolled or mounted almost anywhere. This makes it perfect for cooling warehouses and storage containers when products are being temporarily stored inside, as well as when they are being transported to and from lorries.

Easy to install

The Ice Cube is low in capital (operation costs are less than two Euros per day), and easy to install (requiring only mains electricity and water), thereby making it an effective cooling solution for even the smallest food businesses.

It works by a flash evaporation process which forces water to evaporate by increasing the amount of air it is exposed to, using a high-powered cooler. Water from the bottom of the tank of the cube is pumped to the top, and allowed to flow down over the evaporation pads, evenly saturating them.

A powerful blower mounted inside the cube, sucks air through these pads, forcing the water in them to evaporate. As this water evaporates, the air is cooled by up to 20oF. The blower then drives this air up to 80feet, bringing re-humidified, cool air into the environment. The Ice Cube has been designed to effectively circulate this air around a volume of 165m3/m, and at the same time, it removes any hot air and dust from the atmosphere.

This process not only makes the unit ideal for dramatically lowering ambient temperatures, but by producing slightly moist air, it ensures that the humid conditions necessary for products such as vegetables, fruit and flowers, are maintained. Just 3-8per cent water loss can result in the shrivelling, softening, loss of appearance, loss of saleable weight and/or toughening, of fruit and vegetables. Therefore, when foods susceptible to dehydration are outside the temperature controls, the Ice Cube provides a dual benefit.

The unit is a compact 55-in in height by 32-in in width, with a 33-in by 33-in base. It has a 20-gallon water capacity with a flexible ducting kit for easy filling, and comes with a top distribution funnel ­ a asnoot' (9-in x18-in), which dispels cooled air at a height in excess of 11-ft.

With the aid of this high-powered evaporative cooling system, food businesses will be able to keep product stores and working areas cooler for longer, thereby helping to further reduce risk of spoilage.

Richard Mercer is with Scott Products Ltd. Units can be ordered (less than £1400) directly from the company. Tel +44 1606 837787 or email: sales@scottmail.co.uk





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