Analyzing the protective effect of foods on Salmonella enterica transmission

Abstract

One of the most significant hurdles foodbome pathogens encounter is the acid barrier of the stomach. Salmonella, unlike other pathogens like E. coli 0157:H7 has a high infectious dose and is sensitive to low pH (pH 2). I hypothesized that Salmonella survives passage through the acid barrier of the human stomach (pH 1.5-3.5) because of the protective effects of food (i.e. fats). To test this hypothesis an in vitro transmission model (IVTM) was developed. The IVTM was a weeklong passage that was used to evaluate the impact of anaerobic growth, storage temperatures, acid shock, and the intrinsic parameters of food (i.e. fat content and pH) on Salmonella persistence. Transmission of Salmonella incubated in whole milk ( 49%) and skim milk (47%) were statistically different than the control (water) (3%) at 4�C. The results indicate that the presence of Salmonella in milk provides protection and promotes transmission through the IVTM.