Food sample preparation and enrichment for rapid detection

The requirement by food agencies to detect one Salmonella cell in 25g of food represents a limit of detection of 1:10 for the cell itself, and 1:10 for a nucleotide sequence characterizing the genus. Food microbiologists manage the detection daily, using a few $$ of materials, letting microbial cells to multiply (amplify), essentially noise-free, by factors of ≥10. The millions of cells in agar colonies or broth suspensions are detectable by eye or by chemical, biochemical, immunological or DNA-based tests. The disadvantage of techniques for enriching pathogens by incubation is the 24-96h incubation incurred. To meet demands for shorter analytical times, scientists are developing ways to avoid the lengthy incubations that yield large microbial populations, by substituting physical or chemical enrichment for microbial growth.