Salmonella Lab Report

Experiment 21: Salmonella and food contamination

Purpose /Objective
Objective: To test salmonella in spinach sample over five lab periods.

Food contamination of salmonella can cause serious illness. Only small numbers of salmonella need to be found for a food product to be considered contaminated.

Tests used

Pre-enrichment- lactose broth
Selective enrichment broth- with Tetrathionate Brilliant Broth
Selective Plating- Brilliant Green Agar
Isolation of salmonella conformation- is preformed using TSI and LIA

Test results

Tetrathionate Brilliant Green Broth (TGBG)was inoculated from the whirl pack spinach infected bag. TBGB inhibits the growth of organisms other than salmonella. The next test preformed was the Brilliant Green Agar (BGA)
Pre-enrichment lactose broth, helps isolates Salmonella. The bacteria that ferment lactose die off as the Ph drops. Salmonella survives because it does not use lactose. The TBGB broth, is the second step in isolating Salmonella, from other bacteria in the sample. It inhibits the growth Gram-positive microorganisms and some Gram-negative bacilli. Brilliant Green Agar (BGA) isolates salmonella because they do not ferment lactose, so they grow red. LIA and TSI confirm if salmonella is growing on BGA. Spinach sample B tested positive during the LIA and TSI tests. Sample A tested positive for glucose fermentation (TSI test) but negative for alkaline production (LIA). Sample A shows that there can be flaws in this process, since salmonella was detected in one test but not the other. The cause of the this could have been improper inculcation, lack of growth or contamination. In this lab salmonella was both detected and isolated. The two mediums that were used in experiment 21 are for isolation of microorganisms. Then once the microorganism is isolated then we can detect if what is growing is