Based on the standard set by the international food and beverage regulatory authorities, it is imperative to test for Salmonella in food. Salmonella must be totally absent in both food and environmental samples.
This requires constant monitoring for both food & preparative areas throughout the entire food production process.
CompactDry SL: a microbiological test for Salmonella species in food
CompactDry SL is a dehydrated selective chromogenic media for Salmonella identification. Detection of Salmonella contamination is critical in the food manufacturing process. CompactDry SL detects Salmonella using a 20-24 hours pre-enrichment step followed by incubation at 41-43°C on the CompactDry SL plate.
CompactDry SL uses a combination of different test principles based on bacterial motility and specific chromogenic coloration.
The first indication of the presence of Salmonella is a yellowing of the blue/purple media caused by Salmonella lysine decarboxylase. As the motile Salmonella spread across the plate, the blue/purple plate also becomes yellow, mirroring the Salmonella motility.
Subsequent and/or concomitant greening of the colony is caused by decomposition of chromogenic substrate by a specific Salmonella enzyme. Black/green colonies are generated by the hydrogen sulphide producing Salmonella.
To interpret Salmonella positive results, you will observe a spread of black/green individual or fused colonies and a colour change of the CompactDry SL Salmonella selective chromogenic media from the normal blue/purple colour to yellow.
At a very high Salmonella concentration, the entire salmonella test plate will become yellow with dense plaques of green/black colonies.