Submitted to: Applied and Environmental Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/30/2007
Publication Date: 7/1/2007
Citation: Sharma, M., Kniel, K., Derevianko, A., Ling, J., Bhagwat, A.A. 2007. Sensitivity of Escherichia albertii, a potential foodborne pathogen, to food preservation treatments. Applied and Environmental Microbiology. 73(13):4351-4353. Interpretive Summary: Escherichia albertii is a potential foodborne pathogen because of its ability to cause diarrheal disease and its presence in several foodstuffs. It shares several virulence factors with E. coli O157:H7 which allow it to cause illness. The objective of this research was to determine the tolerance of E. albertii to common food processing treatments such as heat, acid and hydrostatic pressure, and compare it to several strains of E. coli O157:H7 and Shigella spp. Overall, E. albertii was less tolerant to heat, acid and pressure than E. coli O157:H7. Different strains of E. albertii displayed various tolerances to stresses, with strain 19982 the most tolerant to heat and pressure, while strain 9194 was the most tolerant to acid. All E. albertii strains displayed more acid tolerance than a strain of E. coli O157:H7 lacking crucial stress response mechanisms. This is the first reported study on E. albertii and its tolerance to food processing treatments. More work is warranted to determine why E. albertii strains have different tolerances to heat, acid and pressure, and to ensure existing food preservation treatments are effective in controlling this pathogen.
Technical Abstract: Escherichia albertii is a potential foodborne pathogen because of its documented ability to cause diarrheal disease by producing attachment and effacement lesions. Its tolerance to food preservation treatments has not been investigated. Heat, acid, and pressure tolerance were determined for stationary phase cells of five strains of E. albertii, two strains of E. coli O157:H7, and two strains of Shigella spp. D56 deg C values, population reductions after pH 3.0 for 2 h at 37 deg C and after treatment with 500 MPa hydrostatic pressure were determined. D56 deg C values of strains 10457 and 19982 of E. albertii were significantly (P<0.05) greater than those of strains 9194, 10790, and 12502. Populations of wild-type E. coli O157:H7 and Shigella spp. had greater acid tolerance than those of all E. albertii strains. Cells of strains 9194, 10790, and 12502 displayed greater acid tolerances than those of strains 10457 and 12502. After 5 min of pressure treatment, cells of wild-type E. coli O157:H7 and S. flexneri were significantly more tolerant than those of E. albertii strains. Strain 19982 had a significantly higher pressure tolerance than strain 12052 after 5 min treatments, but was not more tolerant than other E. albertii strains. Significant differences in tolerances of strains of E. albertii to heat, acid and pressure were observed. For all treatments, no strain of E. albertii was more tolerant than wild-type E. coli O157:H7, but all strains showed significantly greater acid tolerance than rpoS-deficient E. coli O157:H7. This study is the first to report the tolerance of E. albertii to food preservation treatments.