Packaging Hot Food: New SFP Light Steam-Flushing System Saves Energy Costs
By MULTIVAC Canada Inc.
Wolfertschwenden, Dec. 7, 2022 — Soups, ravioli or noodles: Up to now caterers and kitchens have had to allow hot food to cool down, in order for it to be vacuum packed effectively. This costs time and reduces flexibility — and in the case of active cooling this also takes energy. The alternative from MULTIVAC the packaging specialists: the new SFP Light steam-flushing system.
Fun fact: It is impossible to cook an egg on Mount Everest. Because the lower the air pressure, the lower the boiling point of water. Water vapourizes at 70 degrees Celsius on the highest mountain in the world, which is 8,848 metres above sea level. But 83 degrees Celsius is required for an egg to become hard. No problem for mountaineers. They do without or switch to a steam cooker. But the physical principle presents a challenge to caterers and central kitchens — particularly if they want to use a packaging machine to vacuum-pack hot food directly after cooking, so that the shelf life can be extended. Why? Here the so-called vapour pressure curve comes into play. The greater the negative pressure, the lower the boiling point — exactly as on the mountain. If the machine creates a negative pressure of 200 mbar for example, the water content in the product vapourizes at 60 degrees centigrade. From this point onwards, it is no longer possible to reduce the pressure any further.
That is the problem: When vacuum-packing hot food, some residual air remains, which can adversely affect the shelf life
When vacuum packing hot products, some residual air with 21 percent oxygen content always remains in the header space. A residual air content that can reduce the shelf life of the food. “Many caterers and kitchens therefore let the hot food cool down before vacuum packing. Or they use active cooling. But by doing this, they lose either time or energy,” says Dominik Eberhard, Product Manager for Thermoforming Packaging Machines at MULTIVAC. “In order to ease the burden on caterers and kitchens, we have launched a new steam-flushing system for small to medium batch sizes onto the market, and this is called SFP Light.” SFP is an abbreviation for Steam Flush Packaging.
The solution: The SFP Light steam-flushing system packs hot products without a vacuum source
The thermoforming packaging machine first forms the pack cavities for the product from a plastic film — for packing five kilograms of goulash for example at a temperature of 60 degrees Celsius. The portions then travel into a hermetically enclosed sealing station. Hot steam at a temperature of 180 degrees Celsius now flows through the station. Finally the upper web is sealed to the formed film, and the steam remains in the pack. The secret: Gases have a significantly greater volume than liquids. When the steam turns to water again during cooling, the pack automatically contracts. “Thanks to SFP Light, it is possible to pack hot products without any significant residual air pockets. And all this without any vacuum source, which always has a limited effect due to the vapour pressure curve,” explains Dominik Eberhard. “There is also no danger of the products boiling or packs bursting, since there is no negative pressure in the product space.” Another beneficial side effect of the steam-flushing system: The hot gas at 180 degrees Celsius kills bacteria on the surface of the food, so that the shelf life is extended.
And why SFP Light? “MULTIVAC has offered a SFP system for many years now for thermoforming packaging machines with high throughputs on an industrial scale. The new version is designed for smaller batch sizes in kitchens and catering companies. It is less complex as well as being space-saving and more cost-effective.”
MULTIVAC is one of the leading providers worldwide of packaging solutions for food products of all types, life science, and healthcare products, as well as industrial items. The MULTIVAC portfolio covers virtually all requirements of processors and producers in terms of pack design, output and resource efficiency. It comprises a wide range of packaging technologies, as well as automation solutions, labellers, and quality control systems. The product range is rounded off with solutions upstream of the packaging process in the areas of portioning and processing, as well as bakery technology. Thanks to our extensive expertise in packaging lines, all modules can be integrated into complete solutions. This means that MULTIVAC solutions guarantee a high level of operational and process reliability, as well as efficiency. The MULTIVAC Group has approximately 6,900 employees worldwide, with some 2,400 based at its headquarters in Wolfertschwenden. With over 80 subsidiaries, the Group is represented on all continents. More than 1,000 sales advisors and service technicians throughout the world use their know-how and experience to the benefit of customers, and they ensure all installed MULTIVAC machines are utilized to their maximum. Further information can be found at: www.multivac.com.