Cardinal parameter meta-regression models describing Listeria monocytogenes growth in broth

Beatriz Nunes Silva; Vasco Cadavez; José António Teixeira; Mariem Ellouze; Ursula Gonzales-Barron

doi:10.1016/j.foodres.2020.109476

Cardinal parameter meta-regression models describing Listeria monocytogenes growth in broth

Food Res Int. 2020 Oct:136:109476. doi: 10.1016/j.foodres.2020.109476. Epub 2020 Jun 28.

Authors

Beatriz Nunes Silva¹, Vasco Cadavez², José António Teixeira³, Mariem Ellouze⁴, Ursula Gonzales-Barron⁵

Affiliations

¹ Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal; CEB - Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
² Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal.
³ CEB - Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
⁴ Nestlé Research Centre, PO BOX44, CH-1000 Lausanne 26, Switzerland.
⁵ Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal. Electronic address: ubarron@ipb.pt.

PMID: 32846559
DOI: 10.1016/j.foodres.2020.109476

Abstract

Since Listeria monocytogenes has a high case-fatality rate, substantial research has been devoted to estimate its growth rate under different conditions of temperature, pH and water activity (a_w). In this study, published findings on L. monocytogenes growth in broth were extracted and unified by constructing meta-regression models based on cardinal models for (i) temperature (CM[T]), (ii) temperature and pH (CM[T][pH]), and (iii) temperature, pH and a_w (CM[T][pH][a_w]). After assessing all the sources retrieved between 1988 until 2017, forty-nine primary studies were considered appropriate for inclusion. Apart from the modelling variables, study characteristics such as: type of broth (BHI, TSB, TPB), reading method (colony-forming-units, CFU; or binary-dilution optical density methods, OD), inoculum concentration and strain serotype, were also extracted. Meta-regressions based on CM[T] and CM[T][pH] were fitted on subsets of the 2009 growth rate measures and revealed that type of broth and reading method significantly modulated the cardinal parameter estimates. In the most parsimonious CM[T][pH][a_w] meta-regression model, whereby the variability due to type of broth was extracted in a nested random-effects structure, the optimum growth rate μ_opt of L. monocytogenes was found to be lower when measured as CFU (0.947 log CFU/h; SE = 0.094 log CFU/h) than when measured as OD (1.289 log CFU/h; SE = 0.092 log CFU/h). Such a model produced the following cardinal estimates: T_min = -1.273 °C (SE = 0.179 °C), T_opt = 37.26 °C (SE = 0.688 °C), T_max = 45.12 °C (SE = 0.013 °C), pH_min = 4.303 (SE = 0.014), pH_opt = 7.085 (SE = 0.080), pH_max = 9.483 (SE = 0.080), a_w_min = 0.894 (SE = 0.002) and a_w_opt = 0.995 (SE = 0.001). Integrating the outcomes from numerous L. monocytogenes growth experiments, this meta-analysis has estimated pooled cardinal parameters that can be used as reference values in quantitative risk assessment studies.

Keywords: Growth experiments; Kinetic parameters; Meta-analysis; Predictive microbiology; Secondary model.

Publication types

Meta-Analysis
Research Support, Non-U.S. Gov't

MeSH terms

Colony Count, Microbial
Food Microbiology
Listeria monocytogenes*
Models, Biological
Temperature