Hot Air Treatment for Surface Decontamination of Table Eggs

Hot air pasteurisation was investigated in the RESCAPE project as innovative treatment for surface bacterial decontamination of table eggs. Possible side effects of the treatment on egg quality traits were also studied. Each egg was submitted simultaneously to two flows of hot air generated by two electric heathers (above the eggs) and one flow of air at room temperature (below the egg). The selected thermal cycle was characterised by two shots of hot air at 600°C for 8 sec, each shot, with a cooling interval of 32 sec between the two shots. The decontamination power of the selected thermal treatment was evaluated over one month on shell eggs experimentally inoculated with either Salmonella Enteritidis, Escherichia coli, Listeria monocytogenes and on shell eggs containing only the indigenous microflora. The S. Enteritidis load on treated eggs was lower than the positive control until day 21 with a mean of 1,3 log reduction. A similar log reduction of 1,2 log was observed on L. monocytogenes load of eggs immediately after the treatment. No statistically significant results were obtained comparing E. coli on treated and untreated eggs as well as indigenous microflora on treated and untreated eggs. No detrimental effects on quality traits immediately after the treatment as well as after 28 days of storage at 20°C were recorded.