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Several Salmonella enterica serotypes were isolated from unpasteurized orange juice samples analysed as a follow-up to an outbreak in 1999 of S. enterica serotype Muenchen in the Pacific Northwest regions of United States. Eleven S. enterica strains were serotyped and identified as S. enterica serotype Muenchen (2), S. enterica serotype Hidalgo (2), S. enterica serotype Alamo (1), S. enterica serotype Gaminera (2), S. enterica serotype Javiana (2) and a new serotyped strain S. enterica serotype Tempe (2). The identity of the new serotype S. enterica serovar Tempe serotype 30:b:1,7:z33 was confirmed by the National Salmonella Reference Laboratory at NCID/CDC, Atlanta. These strains were sensitive to ampicillin, chloramphenicol, kanamycin, tetracycline, streptomycin and sulfisoxazole antibiotics. Isolates were screened for invasion (invA) and virulence (spvC) genes using specific primers for these two genes by polymerase chain reaction. All strains were positive for invA gene giving 321-bp fragment, however negative to virulence spvC gene. For pulsed-field gel electrophoresis (PFGE) analysis, Salmonella strain plugs were made and digested with XbaI and subjected to 18-h electrophoresis. The PFGE patterns were different for each S. enterica serotypes suggesting the several origins of contamination in outbreak. S. enterica serotype.

The efficacy of cleaning and sanitation in a small apple cider processing plant was evaluated by surface swab methods as well as microbiological examination of incoming raw ingredients and of the final product. Surface swabs revealed that hard-to-clean areas such as apple mills or tubing for pomace and juice transfer may continue to harbor contaminants even after cleaning and sanitation. Use of poor quality ingredients and poor sanitation led to an increase of approximately 2 logs in aerobic plate counts of the final product. Reuse of uncleaned press cloths contributed to increased microbiological counts in the finished juice. Finally, using apples inoculated with Escherichia coli K-12 in the plant resulted in an established population within the plant that was not removed during normal cleaning and sanitation. The data presented in this study suggest that current sanitary practices within a typical small cider facility are insufficient to remove potential pathogens.