New technologies: Pasteurisation of dry foods
Traditional thermal methods are not designed for sanitation of dry (low aw) foods due to the increase in moisture content required and alterations in the quality of the products. In recent years new commercial technologies have been developed for processing dry foods.
These new systems, which have been proven to be suitable for dry food products commonly, use heat with super heated steam, pressure, vacuum or a combination of these processes. The incorporation of movement is important for some of these technologies to ensure uniformity of treatment. Dry products such as: herbs, spices, nuts, seeds, grains, dried fruits and vegetables, cereal mixes and animal feed can be treated with these technologies. While these technologies are suitable for processing dry food products, not all products have been validated for each piece of equipment.
We currently have a Revtech unit onsite for the continuous heat treatment of herbs, spices, nuts, seeds and other dry ingredients. The system incorporates electrical heating with optional heated steam followed by a drying step to remove moisture before packing. The product is conveyed through the tubes of the machine via vibration. The option for re-circulating is available if roasting is required. This machine is specially designed for research on food safety and the development of new products.
Podcast: Pasteurising dry ingredients
R&D report 344: Heat resistance determination of Salmonella in low Aw foods
Technologies for validation, best practice and development of low Aw food and environment decontamination
Salmonella in low aw products
Some examples of Low aw pasteurisation manufacturers
Bühler Barth AG
Norris Thermal Technologies