Jim ThomasAgricultural BiotechnologyUniversity of Lethbridge

1. Identification of traits specific to a pathogen or contaminate

: allows use of specific antibodies or enzyme reactions to identify a contaminate

2. Use of selective media for growth of bacterial pathogens

: inclusion of Cefixime (cephalosporin antibiotic) in Sorbitol-MacConkeygrowth medium for bacteria allows selection for growth of E. coli O157:H7

3. Molecular characterization: allows use of unique genesequences (e.g., toxin genes) to identify some bacteriaand viruses

Epidemiology

: find the source of the problem

Much of our food is processed through central facilities

• recalls are costly

• For most bacterial pathogens need 10, 000 to 100,000 to infect

• E. coli O157:H7 is a Shiga toxin-producing E. coli that was 1st

identified in a human with bloody diarrhea in 1975

• identified as a food-borne pathogen in 1982

• only takes 1 to 10 to infect

• cutbacks in personnel• cutbacks in money• access to organisms• access to information• negative lobby• how will the information

be used (bioterrorism)