【Objective】 To build an in vitro intestinal model which will be used to assess the harm risk caused by foodborne antimicrobial and the resistance bacteria to human health. 【Method】 The Caco-2 intestinal epithelial models after 21 days culture was built

4 groups were divided: negative control group

mix floras group

Salmonella group

mix floras & Salmonella group

the time for co-culture was 4h. The 16S rDNA fragment of each flora before and after co-culture by quantitative fluorescence PCR was quantified respectively

and the changes of Caco-2 cells intestinal integrity were evaluated by detecting Trans-epithelial electrical resistance (TEER) and the immunofluorescence staining image of tight junction protein ZO-1. 【Results】 From the 16S r DNA fragment of four intestinal floras quantified by qPCR

there were no significant changes between alone cultured and the mixed culture (P>0.05)

the 2 aerobes grown significantly faster than the growth of the 2 anaerobes (P<0.01). B/E was near 100:1

showed that the aerobes were dominant bacteria. Compared with the negative control

TEER and ZO-1 distribution in mix floras group had no significant change and revealed that there were no significant damages to the integrity of Caco-2 intestinal epithelial cells

while in Salmonella group

TEER reduced significantly

and the destruction of ZO-1 structure was observed. But the damages in mix floras & Salmonella group (mixed floras pre-planted) could be some extent reduced. 【Conclusion】This research built an primary in vitro co-culture intestinal epithelial model with Caco-2 cell and 4 intestinal floras-Bifidobacterium lactis

Lactobacillus plantum

Escherichia coli and Enterococcus faecalis. The model showed the certain stability and biological activity. Normal intestinal flora had inhibitory effect to invasive salmonella. Furthermore

we will refine the model to lay the foundation to study the interaction of foodborne antimicrobial drug

drug resistant bacteria and intestinal system.