Direct in situ viability assessment of bacteria in probiotic dairy products using viability staining in conjunction with confocal scanning laser microscopy

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TY  - JOUR
  - Auty, MAE,Gardiner, GE,McBrearty, SJ,O'Sullivan, EO,Mulvihill, DM,Collins, JK,Fitzgerald, GF,Stanton, C,Ross, RP
  - 2001
  - January
  - Applied and Environmental Microbiology
  - Direct in situ viability assessment of bacteria in probiotic dairy products using viability staining in conjunction with confocal scanning laser microscopy
  - Validated
  - ()
  - FLOW-CYTOMETRY LACTOBACILLUS-BULGARICUS DIRECT ENUMERATION BIFIDOBACTERIA STRAINS FLUOROCHROMES CULTURES CHEESE MILK
  - 67
  - 420
  - 425
  - The viability of the human probiotic strains Lactobacillus paracasei NFBC 338 and Bifidobacterium sp. strain UCC 35612 in reconstituted skim milk was assessed by confocal scanning laser microscopy using the LIVE/DEAD BacLight viability stain. The technique was rapid (<30 min) and clearly differentiated live from heat-killed bacteria. The microscopic enumeration of various proportions of viable to heat killed bacteria was then compared with conventional plating on nutrient agar. Direct microscopic enumeration of bacteria indicated that plate counting led to an underestimation of bacterial numbers, which was most likely related to clumping. Similarly, LIVE/DEAD BacLight staining yielded bacterial counts that were higher than cell numbers obtained by plate counting (CFU) in milk and fermented milk These results indicate the value of the microscopic approach for rapid viability testing of such probiotic products. In contrast, the numbers obtained by direct microscopic counting for Cheddar cheese and spray-dried probiotic milk powder were lower than those obtained by plate counting. These results highlight the limitations of LIVE/DEAD BacLight staining and the need to optimize the technique for different strain-product combinations. The minimum detection limit for in situ viability staining in conjunction with confocal scanning laser microscopy enumeration was 10(8) bacteria/ml (equivalent to similar to 10(7) CFU/ml), based on Bifidobacterium sp. strain UCC 35612 counts in maximum-recovery diluent.
DA  - 2001/01
ER  - 
@article{V43338702,
   = {Auty,  MAE and Gardiner,  GE and McBrearty,  SJ and O'Sullivan,  EO and Mulvihill,  DM and Collins,  JK and Fitzgerald,  GF and Stanton,  C and Ross,  RP },
   = {2001},
   = {January},
   = {Applied and Environmental Microbiology},
   = {Direct in situ viability assessment of bacteria in probiotic dairy products using viability staining in conjunction with confocal scanning laser microscopy},
   = {Validated},
   = {()},
   = {FLOW-CYTOMETRY LACTOBACILLUS-BULGARICUS DIRECT ENUMERATION BIFIDOBACTERIA STRAINS FLUOROCHROMES CULTURES CHEESE MILK},
   = {67},
  pages = {420--425},
   = {{The viability of the human probiotic strains Lactobacillus paracasei NFBC 338 and Bifidobacterium sp. strain UCC 35612 in reconstituted skim milk was assessed by confocal scanning laser microscopy using the LIVE/DEAD BacLight viability stain. The technique was rapid (<30 min) and clearly differentiated live from heat-killed bacteria. The microscopic enumeration of various proportions of viable to heat killed bacteria was then compared with conventional plating on nutrient agar. Direct microscopic enumeration of bacteria indicated that plate counting led to an underestimation of bacterial numbers, which was most likely related to clumping. Similarly, LIVE/DEAD BacLight staining yielded bacterial counts that were higher than cell numbers obtained by plate counting (CFU) in milk and fermented milk These results indicate the value of the microscopic approach for rapid viability testing of such probiotic products. In contrast, the numbers obtained by direct microscopic counting for Cheddar cheese and spray-dried probiotic milk powder were lower than those obtained by plate counting. These results highlight the limitations of LIVE/DEAD BacLight staining and the need to optimize the technique for different strain-product combinations. The minimum detection limit for in situ viability staining in conjunction with confocal scanning laser microscopy enumeration was 10(8) bacteria/ml (equivalent to similar to 10(7) CFU/ml), based on Bifidobacterium sp. strain UCC 35612 counts in maximum-recovery diluent.}},
  source = {IRIS}
}
AUTHORSAuty, MAE,Gardiner, GE,McBrearty, SJ,O'Sullivan, EO,Mulvihill, DM,Collins, JK,Fitzgerald, GF,Stanton, C,Ross, RP
YEAR2001
MONTHJanuary
JOURNAL_CODEApplied and Environmental Microbiology
TITLEDirect in situ viability assessment of bacteria in probiotic dairy products using viability staining in conjunction with confocal scanning laser microscopy
STATUSValidated
TIMES_CITED()
SEARCH_KEYWORDFLOW-CYTOMETRY LACTOBACILLUS-BULGARICUS DIRECT ENUMERATION BIFIDOBACTERIA STRAINS FLUOROCHROMES CULTURES CHEESE MILK
VOLUME67
ISSUE
START_PAGE420
END_PAGE425
ABSTRACTThe viability of the human probiotic strains Lactobacillus paracasei NFBC 338 and Bifidobacterium sp. strain UCC 35612 in reconstituted skim milk was assessed by confocal scanning laser microscopy using the LIVE/DEAD BacLight viability stain. The technique was rapid (<30 min) and clearly differentiated live from heat-killed bacteria. The microscopic enumeration of various proportions of viable to heat killed bacteria was then compared with conventional plating on nutrient agar. Direct microscopic enumeration of bacteria indicated that plate counting led to an underestimation of bacterial numbers, which was most likely related to clumping. Similarly, LIVE/DEAD BacLight staining yielded bacterial counts that were higher than cell numbers obtained by plate counting (CFU) in milk and fermented milk These results indicate the value of the microscopic approach for rapid viability testing of such probiotic products. In contrast, the numbers obtained by direct microscopic counting for Cheddar cheese and spray-dried probiotic milk powder were lower than those obtained by plate counting. These results highlight the limitations of LIVE/DEAD BacLight staining and the need to optimize the technique for different strain-product combinations. The minimum detection limit for in situ viability staining in conjunction with confocal scanning laser microscopy enumeration was 10(8) bacteria/ml (equivalent to similar to 10(7) CFU/ml), based on Bifidobacterium sp. strain UCC 35612 counts in maximum-recovery diluent.
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