title: Inactivation of Salmonella during cocoa roasting and chocolate conching.
abstract: The high heat resistance of Salmonella in foods with low water activity raises particular issues for food safety, especially chocolate, where outbreak investigations indicate that few colony-forming units are necessary to cause salmonellosis. This study evaluated the efficiency of cocoa roasting and milk chocolate conching in the inactivation of Salmonella 5-strain suspension. Thermal resistance of Salmonella was greater in nibs compared to cocoa beans upon exposure at 110 to 130°C. The D-values in nibs were 1.8, 2.2 and 1.5-fold higher than those calculated for cocoa beans at 110, 120 and 130°C. There was no significant difference (p>0.05) between the matrices only at 140°C. Since in the conching of milk chocolate the inactivation curves showed rapid death in the first 180 min followed by a lower inactivation rate, and two D-values were calculated. For the first time interval (0-180 min) the D-values were 216.87, 102.27 and 50.99 min at 50, 60 and 70°C, respectively. The other D-values were determined from the second time interval (180-1440 min), 1076.76 min at 50°C, 481.94 min at 60°C and 702.23 min at 70°C. The results demonstrated that the type of matrix, the process temperature and the initial count influenced the Salmonella resistance.
authors.affiliation: Institute of Food Technology, Avenida Brasil 2880, Campinas, São Paulo, Brazil. mnascimento@ital.sp.gov.br
authors.forename: Maristela da Silva do
authors.initials: Mda S
authors.lastname: Nascimento
authors.forename: Daniela Merlo
authors.initials: DM
authors.lastname: Brum
authors.forename: Pamela Oliveira
authors.initials: PO
authors.lastname: Pena
authors.forename: Maria Isabel
authors.initials: MI
authors.lastname: Berto
authors.forename: Priscilla
authors.initials: P
authors.lastname: Efraim
mesh_terms: D058491:Bacterial Load; D002099:Cacao / Q000382:microbiology*; D005511:Food Handling / Q000379:methods*; D005516:Food Microbiology / Q000379:methods*; D006358:Hot Temperature; D050296:Microbial Viability; D012475:Salmonella / Q000502:physiology*; D012478:Salmonella Food Poisoning / Q000517:prevention & control