Application of thermal disinfestations in the food industry

Abstract: With the phase out of methyl bromide, there is renewed interest in using heat tocontrol stored product insects. The heat sterilization technique in flour mills and food processingfacilities uses high target temperatures ranging from 50°C to 60°C to kill stored product insectsby inducing dehydration and/or protein coagulation or enzyme destruction. The length of timerequired to destroy stored product insects varies from a few hours for a piece of machinery to upto 24 hours for a large facility. The key to successfully eradicating the insects is achieving thetarget temperatures for a long enough period of time to reach lethal temperatures in areas such asmachinery interiors, voids, dust collectors, and piping where stored product insects may befound. A specially designed duct system using a flow through system has been adopted forthermal disinfestation of machinery to be treated in food facilities. Thermal disinfestation ofwood pallets is an accepted technology in many countries; 56°C at core temperature of the palletsfor at least 30 minutes is required. Thermal disinfestation of Medjool variety dates is successfullyimplemented as an alternative to methyl bromide in Israel. All Israeli dates packing houses haveadopted the method for this date cultivar. To study the implementation of the method to otherdate varieties, trials were carried out on: Deglet-Noor in branches and Zahidi in bulk (in Dolevtype crates, 200kg capacity), and Halawy in factory type boxes. Laboratory and commercial scaledisinfestation trials failed to cause changes in the colour of the branches and the dates of Deglet-Noor. In commercial scale trials with Halawy date cultivar stored in factory boxes (12kgcapacity), air flow rate and temperature increase rate, suitable for thermal disinfestation, could beachieved.