title: Design of challenge testing experiments to assess the variability of Listeria monocytogenes growth in foods.
abstract: The assessment of the evolution of micro-organisms naturally contaminating food must take into account the variability of biological factors, food characteristics and storage conditions. A research project involving eight French laboratories was conducted to quantify the variability of growth parameters of Listeria monocytogenes obtained by challenge testing in five food products. The residual variability corresponded to a coefficient of variation (CV) of approximately 20% for the growth rate (μ(max)) and 130% for the parameter K = μ(max) × lag. The between-batch and between-manufacturer variability of μ(max) was very dependent on the food tested and mean CV of approximately 20 and 35% were observed for these two sources of variability, respectively. The initial physiological state variability led to a CV of 100% for the parameter K. It appeared that repeating a limited number of three challenge tests with three different batches (or manufacturers) and with different initial physiological states seems often necessary and adequate to accurately assess the variability of the behavior of L. monocytogenes in a specific food produced by a given manufacturer (or for a more general food designation).
authors.affiliation: Ecole Nationale Vétérinaire d'Alfort, Unité Microbiologie des Aliments-Sécurité et Qualité (MASQ), Maisons-Alfort Cedex, France. jcaugustin@vet-alfort.fr
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Augustin
authors.forename: Hélène
authors.initials: H
authors.lastname: Bergis
authors.forename: Graziella
authors.initials: G
authors.lastname: Midelet-Bourdin
authors.forename: Marie
authors.initials: M
authors.lastname: Cornu
authors.forename: Olivier
authors.initials: O
authors.lastname: Couvert
authors.forename: Catherine
authors.initials: C
authors.lastname: Denis
authors.forename: Véronique
authors.initials: V
authors.lastname: Huchet
authors.forename: Sabrina
authors.initials: S
authors.lastname: Lemonnier
authors.forename: Anthony
authors.initials: A
authors.lastname: Pinon
authors.forename: Michèle
authors.initials: M
authors.lastname: Vialette
authors.forename: Véronique
authors.initials: V
authors.lastname: Zuliani
authors.forename: Valérie
authors.initials: V
authors.lastname: Stahl
mesh_terms: D000818:Animals; D002645:Chickens; D015169:Colony Count, Microbial; D005396:Fish Products / Q000382:microbiology*; D005399:Fishes; D005516:Food Microbiology / Q000379:methods*; D008089:Listeria monocytogenes / Q000254:growth & development*; D008461:Meat Products / Q000382:microbiology*; D008954:Models, Biological; D011202:Poultry Products / Q000382:microbiology*; D012107:Research Design; D013552:Swine