Using Microbial Responses Viewer and a Regression Approach to Assess the Effect of pH, Activity of Water and Temperature on the Survival of Campylobacter spp.

Hayrunisa Icen,Maria Rosaria Corbo,Milena Sinigaglia,Burcu Irem Omurtag Korkmaz,Antonio Bevilacqua

doi:10.3390/foods11050637

Hayrunisa Icen, Maria Rosaria Corbo + Show 3 more

Open Access

https://doi.org/10.3390/foods11050637

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Abstract

This study aimed at developing a model for evaluating the survival of various Campylobacter jejuni strains under different conditions in culture media and poultry data from ComBase. Campylobacter data of culture media (116) and poultry (19) were collected from Microbial Responses Viewer, an additional tool of ComBase. The Weibull equation was selected as a suitable model for the analysis of survival data because of the nonlinearity of survival curves. Then, the fitting parameters (first reduction time and shape parameter) were analysed through a Kruskall–Wallis test and box-whisker plots, thus pointing out the existence of two classes of temperature (0–12 °C and 15–25 °C) and pH (4–6.5 and 7–7.5) acting on the viability of C. jejuni. Finally, a general regression model was used to build a comprehensive function; all factors were significant, but temperature was the most significant variable, followed by pH and water activity. In addition, desirability and prediction profiles highlighted a negative correlation of the first reduction time with temperature and a positive correlation with pH and water activity.

Highlights

Campylobacter spp. are commensal organisms in bovine, sheep, pigs and poultry alongside various birds and usually do not cause any symptoms in animals
The main assumption of the models described and in the following ones is that C. jejuni experiences only a death kinetic, as reported by Microbial Responses Viewer (MRV)
Campylobacter survival in MRV is described by a linear model; for several situations, the time-dependent survival kinetics of the strains cannot be explained by the linear model because there were some deviations from linearity

Summary

Introduction

Campylobacter spp. are commensal organisms in bovine, sheep, pigs and poultry alongside various birds and usually do not cause any symptoms in animals. They are Gramnegative, slender, spirally curved rod, non-spore-forming and microaerophilic bacteria [1,2]. It is known that there are 51 species and 16 subspecies belonging to the Campylobacter genus of the Campylobacteraceae family. Two subspecies belong to the species Campylobacter jejuni: Campylobacter jejuni subsp. Campylobacteriosis is an infectious disease generally caused by C. jejuni, but C. coli, C. concisus, C. upsaliensis, C. ureolyticus, C. hyointestinalis and C. sputorum give rise to this infection [4]. It is seen that C. jejuni and C. coli are the most important and most resistant to physical conditions. There are complications such as Guillain–Barré syndrome after infection [5]

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