Disinfection of fishmeal with radiofrequency heating for improved quality and energy efficiency

Radiofrequency (RF) heating was investigated as an alternative to cooking, drying or chemical disinfection for the preservation of fishmeal and shown to be a highly effective process without any detectable effects, particularly on proteins, lipids or in vivo digestibility. The uniform and deep penetration of RF waves resulted in rapid and homogeneous heating allowing ∼4 times lower thermal loads to be used for >5 log₁₀ (>99.999%) reduction in infection levels for Salmonella spp and for Escherichia coli O157:H7. Simultaneously, the natural flora was reduced by >3 log₁₀ (>99.9%). The RF process can be operated in the 70-90°C range and with high energy-use efficiency (∼50%), which compares well with the 10-15% efficiency for conventional surface heating methods. Industry and expert laboratories confirmed these results. RF heating is thus a new alternative thermal process that is particularly appropriate for disinfecting fishmeal or for reprocessing it rapidly and efficiently with full retention of its natural attributes.