Prediction of the Growth of Staphylococcus aureus in Chicken Sausage

Abstract

This research studied the effect of low temperature (-5, 2.5, and 10 °C) and the initial member of S. aureus (0 to 100 cfu gram-1) on the growth curve of S. aureus in chicken sausage, in order to determine the growth rate and lag phase model of S. aureus. The data were plotted and fitted using Response Surface Methodology (RSM) to obtain the growth models of the bacteria under defined conditions. Steps of the study included sample preparation (preparation and confirmation of inoculum following by inoculation of S. aureus cultures on chicken sausage samples), determining the growth pattern of S. aureus ATCC 25923 in chicken sausage at storage temperature 35-37 ºC and 25-30 ºC for 24 hours, as well as at -5 to 10 ºC for 1 to 2 week. The data were then proced using RSM to obtain modelling, model validation, and growth curves plotting based on the Baranyi equation. Growth rate of S. aureus (cfu gram-1 day-1) with concentration factor 0, 20, dan 100 cfu gram-1 and storage temperature -5 until 10 °C in BPA + egg yolk tellurite is y = 0.0093 + 0.0158 temperature + 0.0011 concentration + 0.0003 temperature *concentration. R2 0.60 with confident level 95%. Lag time of S. aureus (day) with concentration factor 0, 20, dan 100 cfu gram-1 and storage temperature -5 until 10 °C in BPA + egg yolk tellurite is y = 0.1680 + 0.0193 temperature + 0.2857 concentration + 0.0052 temperature*concentration. R2: 0.58 with confident level 95%.