title: Survival kinetics of Listeria monocytogenes on raw sheep milk cured cheese under different storage temperatures.
abstract: Raw sheep milk cured cheese produced in the Castilla y Leon region (Spain) constitutes a traditional semi-hard aromatic cheese typically aged for three to six months. This product is catalogued as ready-to-eat since it is not submitted to any further treatment before consumption. Thus, foodborne pathogens such as Listeria monocytogenes can represent a health concern for susceptible consumers. This study was aimed at evaluating the survival of L. monocytogenes on raw sheep milk cured cheese under different storage temperatures. Log-linear+shoulder and Weibull type models were fitted to data observed in order to estimate kinetic parameters. The Arrhenius relationship was further used to predict the impact of temperature on L. monocytogenes behavior during storage at 4, 12 and 22°C. Additionally, growth of lactic acid bacteria (LAB) as a representative group of the indigenous microbiota was evaluated. Results obtained indicated that the time to eradication (time when absence of L. monocytogenes in the analyzed samples was observed) was 114, 104, and 77 days for cheese samples stored at 4, 12 and 22°C, respectively. The LAB population showed an increase at 12 and 22°C during storage. However, an increase of 1 log CFU/g was observed during the first 2 weeks irrespectively of the storage temperature. The log-linear+shoulder model indicated a good fit to observed data. Likewise, the Arrhenius relationship explained sufficiently the dependency of temperature on L. monocytogenes behavior. This study demonstrated that cheese storage at ambient temperatures could lead to the preservation of its quality properties as well as its safety against L. monocytogenes.
authors.affiliation: Department of Food Science and Technology, University of Cordoba, Campus de Rabanales, Edificio Darwin, 14014 Córdoba, Spain. Electronic address: bt2vadia@uco.es.
authors.forename: Antonio
authors.initials: A
authors.lastname: Valero
authors.affiliation: Subdirección de Investigación y Tecnología, Instituto Tecnológico Agrario de Castilla y León, Carretera de Burgos Km 119, Valladolid, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Hernandez
authors.affiliation: Department of Agricultural and Food Sciences, Alma Mater Studiorum-University of Bologna, Via del Florio 2, 40064 Ozzano dell'Emilia, BO, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: De Cesare
authors.affiliation: Department of Agricultural and Food Sciences, Alma Mater Studiorum-University of Bologna, Via del Florio 2, 40064 Ozzano dell'Emilia, BO, Italy.
authors.forename: Gerardo
authors.initials: G
authors.lastname: Manfreda
authors.affiliation: Subdirección de Investigación y Tecnología, Instituto Tecnológico Agrario de Castilla y León, Carretera de Burgos Km 119, Valladolid, Spain.
authors.forename: Patricia
authors.initials: P
authors.lastname: González-García
authors.affiliation: Subdirección de Investigación y Tecnología, Instituto Tecnológico Agrario de Castilla y León, Carretera de Burgos Km 119, Valladolid, Spain; Microbiology Section, Faculty of Science, University of Burgos, Burgos, Spain. Electronic address: rodlazda@gmail.com.
authors.forename: David
authors.initials: D
authors.lastname: Rodríguez-Lázaro
mesh_terms: D000818:Animals; D002611:Cheese / Q000382:microbiology*; D005511:Food Handling; D005516:Food Microbiology; D007777:Lactobacillaceae / Q000502:physiology; D008089:Listeria monocytogenes / Q000254:growth & development / Q000502:physiology*; D008892:Milk / Q000382:microbiology; D008962:Models, Theoretical; D012756:Sheep; D013030:Spain; D016019:Survival Analysis; D013696:Temperature
keywords: Listeria monocytogenes; Modeling; Raw sheep milk cured cheese; Storage; Survival