In order to improve the animal welfare, the Council Directive 1999/74/EC (defining minimum standards for the welfare of laying hens) will ban conventional cage systems since 2012, in favour of enriched cages or floor systems. As a consequence an increased risk of bacterial contamination of eggshell is expected (EFSA, 2005). This has lead the European Commission to issue a specific project (RESCAPE Food CT 2006-036018) with the aim to search for efficient techniques to reduce eggshell contamination by bacterial pathogens, and thus to prevent any potential or additional food safety risk for Human health. In the present study an eggshell hot air pasteurisation process was set up and its decontamination power was evaluated on the shell of table eggs, experimentally infected with S. Enteritidis, E. coli and L. monocytogenes. To initially search for the best thermal cycle a simplified finite element model, describing the thermal interaction between the air and egg, was developed. The numerical model, that was validated using an egg simulant equipped with thermocouples, permitted to quickly evaluate an high number of testing conditions. Particularly it was solved in transient conditions, as a virtual bench, sampling the parameters space: air temperature; air speed; duration of the treatment; revolving speed of the egg; rest interval between successive treatments. Subsequently a specific apparatus composed by two hot air generators, one cold air generator and rolling cylinder support, was built to physically condition the eggs. The best thermal cycle, selected for the microbiological tests, was characterized by two shots of hot air at 600°C for 8 sec, spaced by a cooling interval of 32 s. The bacterial load of inoculated and not inoculated eggs was investigated at days 0, 1, 2, 3, 8, 10, 15, 21, 24 and 28 post infection. No significant results were obtained comparing E. coli on treated and not treated eggs. On the contrary a mean reduction of 90% of bacterial population was observed on other pathogens. Furthermore no detrimental effects on quality traits of treated eggs were recorded. These results support the hot air pasteurisation technique for the surface decontamination of table eggs as an effective industrial process.
Hot Air Technique for the Decontamination of Table Eggs Surface / A. Fabbri; C. Cevoli; F. Pasquali; G. Manfreda. - STAMPA. - 2:(2009), pp. 1505-1509. (Intervento presentato al convegno “Technology and management to ensure sustainable agriculture, agro-systems, forestry and safety” tenutosi a Reggio Calabria nel 17-19 Giugno 2009).
Hot Air Technique for the Decontamination of Table Eggs Surface
FABBRI, ANGELO;CEVOLI, CHIARA;PASQUALI, FREDERIQUE;MANFREDA, GERARDO
2009
Abstract
In order to improve the animal welfare, the Council Directive 1999/74/EC (defining minimum standards for the welfare of laying hens) will ban conventional cage systems since 2012, in favour of enriched cages or floor systems. As a consequence an increased risk of bacterial contamination of eggshell is expected (EFSA, 2005). This has lead the European Commission to issue a specific project (RESCAPE Food CT 2006-036018) with the aim to search for efficient techniques to reduce eggshell contamination by bacterial pathogens, and thus to prevent any potential or additional food safety risk for Human health. In the present study an eggshell hot air pasteurisation process was set up and its decontamination power was evaluated on the shell of table eggs, experimentally infected with S. Enteritidis, E. coli and L. monocytogenes. To initially search for the best thermal cycle a simplified finite element model, describing the thermal interaction between the air and egg, was developed. The numerical model, that was validated using an egg simulant equipped with thermocouples, permitted to quickly evaluate an high number of testing conditions. Particularly it was solved in transient conditions, as a virtual bench, sampling the parameters space: air temperature; air speed; duration of the treatment; revolving speed of the egg; rest interval between successive treatments. Subsequently a specific apparatus composed by two hot air generators, one cold air generator and rolling cylinder support, was built to physically condition the eggs. The best thermal cycle, selected for the microbiological tests, was characterized by two shots of hot air at 600°C for 8 sec, spaced by a cooling interval of 32 s. The bacterial load of inoculated and not inoculated eggs was investigated at days 0, 1, 2, 3, 8, 10, 15, 21, 24 and 28 post infection. No significant results were obtained comparing E. coli on treated and not treated eggs. On the contrary a mean reduction of 90% of bacterial population was observed on other pathogens. Furthermore no detrimental effects on quality traits of treated eggs were recorded. These results support the hot air pasteurisation technique for the surface decontamination of table eggs as an effective industrial process.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
