Resuscitation of acid-injured Salmonella in enrichment broth, in apple juice and on the surfaces of fresh-cut cucumber and apple.
OBJECTIVE
To investigate the resuscitation of acid-injured Salmonella enterica in selected enrichment broths, in apple juice and on cut surfaces of apple and cucumber slices.


RESULTS
Following exposure to 2.4% acetic acid for 7 min, S. enterica (serovars Mbandaka, Chester and Newport) cells were used to inoculate enrichment broths, phosphate-buffered saline (PBS), apple juice and fruit slices. Injured Salmonella cells resuscitated and regained the ability to form colonies on selective agar (Xylose-Lysine-Tergitol 4) if they were incubated in lactose broth (LB), universal pre-enrichment broth (UPB) or buffered peptone water (BPW), but not in tetrathionate broth, PBS or apple juice. The resuscitation occurred at a significantly (P > 0.05) faster rate in UPB than in LB or BPW. The resuscitation also occurred on the surfaces of fresh-cut cucumber at 20 degrees C, but not at 4 degrees C.


CONCLUSIONS
Acid-injured Salmonella cells resuscitated in nonselective enrichment broths at different rates, but not in selective enrichment broth, apple juice, PBS or on fresh-cut apple.


CONCLUSIONS
Pre-enrichment of food samples in UPB prior to selective enrichment is recommended. Injured Salmonella cells have the ability to resuscitate on fresh-cut surfaces of cucumber when stored at abusive temperatures.
Liao
C-H
CH
Eastern Regional Research Center, Agricultural Research Service, US Department of Agriculture, Wyndmoor, PA 19038, USA. cliao@errc.ars.usda.gov
Fett
W F
WF
D000143:Acids / Q000494:pharmacology; D018553:Cucumis sativus / Q000737:chemistry* / Q000382:microbiology; D003470:Culture Media; D005516:Food Microbiology; D027845:Malus / Q000737:chemistry* / Q000382:microbiology; D012475:Salmonella / Q000187:drug effects / Q000235:genetics / Q000502:physiology*
D000143:Acids; D003470:Culture Media