Radio Killed The Microwave Star

Olaf Blömker, Managing Director of BMPE (Butcher & Meat Processing Equipment), had recently completed the installation of a state-of-the-art RF (Radio Frequency) defroster at one of RCL’s plants when we visited him. At the time, six machines had been sold in Southern Africa in the fish, meat and confectionery industries.

Olaf is passionate about the benefits of RF for its ability to safely and rapidly defrost meats, poultry and fish without compromising quality. The equipment is manufactured by Italian RF specialist Stalam, which BMPE represents across the African continent.

“RF is replacing microwave around the world. It’s way more hygienic,” he says of the technology. RF defrosting uses ultra-high-speed vibration to increase temperatures from -25°C to -2°C in minutes without any blood loss. There’s also no human contact with the product, which can be defrosted inside the box.

The challenge with traditional defrosting

Heat transfer is an intrinsically slow process; the larger the product, the longer the defrosting takes, delaying the next processing stage.
Bacteria can survive at negative storage temperatures, so slow defrosting gives considerable opportunity for bacterial growth.
Proportionally high drip losses result from lengthy defrosting, changing product texture and causing significant financial loss.
Speeding up defrosting by raising temperature causes severe product deterioration.
Long defrosting times force batch processing, with high handling costs and additional risks.
Conventional processes depend on ambient conditions that are difficult to control.

How RF works

The product is placed on a conveyor belt and transferred continuously through the RF tunnel, passing between upper and lower electrode plates connected to a radio frequency generator oscillating at several million cycles per second. The alternating voltage causes the dipolar water molecules of the frozen product to vibrate and rotate, generating heat rapidly and uniformly within the whole product mass — regardless of size, weight, shape or thermal conductivity. Heat generation and defrosting time are accurately controlled through the plate voltage and belt speed.

The benefits

Defrosting in minutes rather than hours or days, even for large blocks — directly inside storage packaging if required.
Speed and uniformity minimise drip loss, deterioration and bacterial growth, preserving product quality.
Product arrives at the correct temperature for the next processing stage.
Continuous processing enables just-in-time production — a great advantage for sudden orders and last-minute changes.
Unaffected by weather or ambient conditions; accurate and consistent control.
Requires far less floor space than traditional defrosting rooms, with drastically reduced process costs.

“After the recent Listeria outbreak, manufacturers are realising that there’s nowhere to hide when it comes to food safety, and a critical hazard point is defrosting. RF will help manufacturers — and their customers.”

Source: BMPE editorial in Food and Beverage Reporter.