In Situ Electrical Conductivity Measurement by Using Confocal Scanning Laser Microscopy

ABSTRACT 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 ∼108 bacteria/ml (equivalent to ∼107 CFU/ml), based on Bifidobacterium sp. strain UCC 35612 counts in maximum-recovery diluent.

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Mechanism of MgO dissolution in MgF2–CaF2–MF (M=Li or Na) melts: Kinetic analysis via in-situ high temperature confocal scanning laser microscopy (HT-CSLM)

Ceramics International ◽

10.1016/j.ceramint.2019.06.298 ◽

2019 ◽

Vol 45 (16) ◽

pp. 20251-20257 ◽

Cited By ~ 2

Author(s):

Yumin Lee ◽

Jae Kyo Yang ◽

Dong Joon Min ◽

Joo Hyun Park

Keyword(s):

High Temperature ◽

Kinetic Analysis ◽

Scanning Laser ◽

Confocal Scanning Laser Microscopy ◽

Laser Microscopy ◽

Scanning Laser Microscopy ◽

Confocal Scanning ◽

Confocal Scanning Laser

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In Situ Localization of Escherichia coli O157:H7 in Food by Confocal Scanning Laser Microscopy

Journal of Food Protection ◽

10.4315/0362-028x-68.3.482 ◽

2005 ◽

Vol 68 (3) ◽

pp. 482-486 ◽

Cited By ~ 27

Author(s):

MARK AUTY ◽

GERALDINE DUFFY ◽

DAVID O'BEIRNE ◽

AOIFE MCGOVERN ◽

ELAINE GLEESON ◽

...

Keyword(s):

Escherichia Coli ◽

Scanning Laser ◽

Confocal Scanning Laser Microscopy ◽

Escherichia Coli O157 ◽

Laser Microscopy ◽

E Coli ◽

Scanning Laser Microscopy ◽

Confocal Scanning ◽

Confocal Scanning Laser

The aim of this study was to use confocal scanning laser microscopy to examine the in situ localization of Escherichia coli O157:H7 on beef (knuckle or brisket) and carrots and in semisoft cheese made from pasteurized milk. Using a combination of specific immunolabeling and dual-excitation confocal scanning laser microscopy, it was possible to clearly demonstrate the localization of E. coli O157:H7 within various food types. In carrots, bacteria were found mainly at cell junctions and in intracellular spaces up to 50 μm deep. In beef, bacteria were located primarily between muscle fibers and within connective tissue (at a depth of 25 μm), whereas in cheese the bacteria occurred singly or in small clumps of up to 10 cells and were observed within the protein matrix of the cheese. These results revealed how E. coli O157:H7 can penetrate beef and carrot surfaces where it is protected from decontamination processes.

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