Title
Zero-inflated binomial regressions for modelling low prevalence of pathogens in chicken meat as affected by sampling site
Date Issued
01 December 2018
Access level
open access
Resource Type
journal article
Author(s)
Polytechnic Institute of Bragança
Publisher(s)
Elsevier B.V.
Abstract
Contamination of raw poultry meat with foodborne pathogens could occur because of improper handling at primary production and slaughterhouse levels. Low microbial prevalence data often consists of a high amount of non-detections (zero positives), so a flexible framework is required to characterise the underlying microbial distribution and conduct reliable inferential statistics. Thus, the objective of this work was to evaluate the performance of zero-inflated binomial (ZIB) regression models to describe the effects of sampling site (carcass, thigh, breast, wings) on the measured incidences of Salmonella, Listeria monocytogenes and Staphylococcus aureus on chicken meat. For each pathogen, four regression models based on the zero-inflated binomial ZIB (p, w0) distribution were fitted to the presence/absence data with sampling site as covariate and random-effects due to sampling occasion either in the binomial probability (p) or in the extra-proportion of non-detections (w0). For the three pathogens, the sampling site exerted a greater effect on w0 than on p itself, with breast bearing the lowest prevalence estimates of Salmonella spp. (mean: 0.88%; 95% CI: 0.02–1.95%) and S. aureus (mean 1.48%; 95% CI: 0.01–4.00%). The fitting capacity of the models was further improved when random effects due to sampling occasion were placed in w0 (deviances decreased from 146.7–156.7 to 140.2–140.6). This would imply that, theoretically, the variability in pathogens’ occurrence from batch to batch mainly arises from the variability in non-contaminated zones. At any sampling site, the mean prevalence was estimated as 1.35 (95% CI: 0.15 – 2.70) for Salmonella, 2.11 (95% CI: 0.04 – 5.63) for L. monocytogenes and 2.36 (95% CI: 0.04 – 5.12) for S. aureus. Sampling performance analysis showed that wings were mostly suitable to detect Salmonella and S. aureus with higher probability (0.016 and 0.035 respectively), while for L. monocytogenes, sampling of thigh could be more effective (0.032).
Start page
28
End page
36
Volume
10
Language
English
OCDE Knowledge area
Biología celular, Microbiología
Enfermedades infecciosas
Subjects
Scopus EID
2-s2.0-85051134196
Source
Microbial Risk Analysis
ISSN of the container
23523522
Sponsor(s)
Funding text
Dr. Gonzales-Barron wishes to acknowledge the financial support provided by the Portuguese Foundation for Science and Technology (FCT) through the award of a five-year Investigator Fellowship (IF) in the mode of Development Grants ( IF/00570 ).
Sources of information:
Directorio de Producción Científica
Scopus