Peristaltics make omelette without breaking (so many) eggs

London - A Japanese food processing company has switched to peristalic technology from Watson-Marlow Bredel to pump egg yolks and whites through a chilling process before despatch to food manufacturers who make extra-thick omelettes for use in sushi.

Chilling approximately 60,000 egg yolks and whites every day, the company had previously used a conventional sine pump, which delivered only 20% of yolks through the process without damage. Sushi in Japan is traditionally served with omelettes cut into portions measuring up to 2cm thick. To guarantee that the quality of the omelette, producers demand as many unbroken egg yolks as possible.

The unnamed food processor asked Iwaki Pumps, which provides sales and support for Watson-Marlow pumps in Japan to improved the rate of undamaged yolks after pump transfer. Iwaki recommended an 840 Series peristaltic metering/transfer pump. The inverter-controlled pump arrived for trials at the Japanese plant, where starting from a low speed the pump velocity was increased to 20rpm, which gave the desired flow rate of around 1000 litres/hour.

During the trials, the Japanese processing staff assessed the yolks and confirmed about 70% were undamaged. According to a  Watson-Marlow spokewoman, the pumps cannot deliver a 100% unbroken rate as eggs are highly shear sensitive and have also to be transfered quickly to prevent them "cooking", which can occur at relatively low temperatures.

The Japanese company is now in the process of upgrading its processing operations to incorporate the 840 Series peristaltic hygienic pump. According to the equipment supplier, the pumps also offers benefits in terms of its hygienic features including clean-in-place and steam-in-place sterilisation at full velocity without the need for bypasses, and stainless steel connectors.