Effects of heat, acid, and freeze-thaw challenges on survival of starved Vibrio parahaemolyticus in minimal salt medium, tryptic soy broth, and filtered oyster homogenate medium.
Vibrio parahaemolyticus is a ubiquitous gram-negative enteropathogenic bacterium. To evaluate the risk of stress-adapted V. parahaemolyticus cells in food, we investigated the survivability of starvation-adapted and starvation-low salinity-adapted cells of this pathogen in different media against different stresses. Logarithmically grown bacterial cells were starved at 25 degrees C in a minimal salt medium with 0.5 or 3.0% NaCl for 24 h. Resistances against challenges of heat, acid, and freeze-thaw treatment exhibited by the starvation-adapted cells were similar to those exhibited by the starvation-low salinity-adapted cells but substantially higher than those of the unadapted control cells. The increased stress resistance of the adapted cells against freeze-thaw challenge was lower in tryptic soy broth than in the starving medium. Resistance of the adapted bacteria against heat and freeze-thaw treatment was completely eliminated in filter-sterilized oyster homogenate medium. Practically, these results help to assess the risk of stress-adapted V. parahaemolyticus in food.
Wong
H C
HC
Department of Microbiology, Soochow University, Taipei, Taiwan 111, Republic of China. wonghc@scu.edu.tw
Chang
C N
CN
Chen
M Y
MY
D000222:Adaptation, Physiological; D015169:Colony Count, Microbial; D003470:Culture Media; D005511:Food Handling / Q000379:methods*; D005516:Food Microbiology; D005615:Freezing; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D013217:Starvation; D013997:Time Factors; D014736:Vibrio parahaemolyticus / Q000254:growth & development* / Q000502:physiology*
D003470:Culture Media