Escherichia coli serotype O157:H7 can cause serious illness or death when consumed in contaminated foods. Outbreaks of foodborne illness have been caused by the consumption of undercooked or raw ground beef, dry-cured salami, unpasteurized fruit juices, raw milk, cheese curds, lettuce, alfalfa sprouts and game meat.[1]

Conventional methods to isolate E. coli O157:H7 from food involve pre-enrichment to resuscitate damaged cells, enrichment and inoculation to selective, differential media such as MacConkey Agar with sorbitol, tellurite and cefixime. Most non-O157:H7 E. coli ferment sorbitol. However, atypical strains, along with other sorbitol nonfermenting bacteria such as Morganella and Hafnia, appear identical to O157:H7 colonies on sorbitol media.

BBL™ CHROMagar™ O157 was developed for the isolation and differentiation of E. coli O157:H7 from food, environmental or clinical samples. The medium distinguishes this virulent strain from non-O157 E. coli using a highly specific chromogenic reaction. E. coli O157:H7 produces mauve-colored colonies on BBL™ CHROMagar™ O157. Gram-negative organisms, other than E. coli O157, will either be inhibited or produce colorless, blue, green or blue-green (aqua) colonies.

BBL™ CHROMagar™ O157 is certified by the AOAC&#;153; - Research Institute (AOAC-RI) under the Performance Tested Methods[SM] Program for the analysis of raw ground beef and unpasteurized apple cider when using FDA BAM, USDA FSIS, and ISO methods.[2-4]

• Sensitivity 100% and specificity 100%
  
• No false negatives were found in testing the food matrices
  
• Detected more positives than the reference method media
  
• Plates read with reportable results 24 hours from sample enrichment
  
• 24-hour growth-based reportable results when using enhanced Buffered Peptone Water enrichment protocol and the PATHATRIX™ IMS Purification/Concentration system.[6,7]
  

Only BBL™ CHROMagar™ Formulations Have AOAC™-RI Approval!