Examples of the use of PFGE are the outbreak of E. coli 0157 infections from baby lettuce in Michigan and Virgina and E. Coli 0157 infections from commercial apple juice. Data for the years 1979-1989 show that resistance in Salmonella is increasing. The sources of isolates in clinical labs from patient specimens are Salmonella, E.coli 0157, and Campylobacter. Dr. Griffin indicated that one-third of Salmonella isolates are the resistant type defined by phage typing in the United Kingdom. Some needs in the current food safety program, Dr. Griffin indicated, are to determine what proportion of diarrhea cases can be explained and to develop rapid and inexpensive diagnosis techniques for diarrheal pathogens as well as improved tests for cyclospora.
Clinical labs encourage culturing for more than routine pathogens.
We need to determine what slaughterhouse practices decrease contamination of ground beef and we need to conduct more applied research. Other needs in the current food safety program include improved detection of cyclospora in the environment and improved detection of viruses in food. Further investigations are needed to determine how E. coli 0157 persists on farms and what factors lead to the emergence of Shiga toxin-producing E. coli. Another need is farm guidelines for appropriate use of antibiotics. There are many opportunities for productive future work.