PMID- 27343426
OWN - NLM
STAT- MEDLINE
DCOM- 20170321
LR  - 20181202
IS  - 1879-3460 (Electronic)
IS  - 0168-1605 (Linking)
VI  - 233
DP  - 2016 Sep 16
TI  - Critical analysis of the maximum non inhibitory concentration (MNIC) method in 
      quantifying sub-lethal injury in Saccharomyces cerevisiae cells exposed to either 
      thermal or pulsed electric field treatments.
PG  - 73-80
LID - S0168-1605(16)30301-4 [pii]
LID - 10.1016/j.ijfoodmicro.2016.06.008 [doi]
AB  - Sub-lethal injury within a microbial population, due to processing treatments or 
      environmental stress, is often assessed as the difference in the number of cells 
      recovered on non-selective media compared to numbers recovered on a "selective 
      media" containing a predetermined maximum non-inhibitory concentration (MNIC) of 
      a selective agent. However, as knowledge of cell metabolic response to injury, 
      population diversity and dynamics increased, the rationale behind the 
      conventional approach of quantifying sub-lethal injury must be scrutinized 
      further. This study reassessed the methodology used to quantify sub-lethal injury 
      for Saccharomyces cerevisiae cells ( approximately  4.75 Log CFU/mL) exposed to either a mild 
      thermal (45 degrees C for 0, 10 and 20min) or a mild pulsed electric field treatment 
      (field strengths of 8.0-9.0kV/cm and energy levels of 8, 14 and 21kJ/kg). Treated 
      cells were plated onto either Yeast Malt agar (YM) or YM containing NaCl, as a 
      selective agent at 5-15% in 1% increments. The impact of sub-lethal stress due to 
      initial processing, the stress due to selective agents in the plating media, and 
      the subsequent variation of inhibition following the treatments was assessed 
      based on the CFU count (cell numbers). ANOVA and a generalised least squares 
      model indicated significant effects of media, treatments, and their interaction 
      effects (P<0.05) on cell numbers. It was shown that the concentration of the 
      selective agent used dictated the extent of sub-lethal injury recorded owing to 
      the interaction effects of the selective component (NaCl) in the recovery media. 
      Our findings highlight a potential common misunderstanding on how culture 
      conditions impact on sub-lethal injury. Interestingly for S. cerevisiae cells the 
      number of cells recovered at different NaCl concentrations in the media appears 
      to provide valuable information about the mode of injury, the comparative 
      efficacy of different processing regimes and the inherent degree of resistance 
      within a population. This approach may provide similar information for other 
      micro-organisms.
CI  - Copyright (c) 2016 Elsevier B.V. All rights reserved.
FAU - Kethireddy, V
AU  - Kethireddy V
AD  - Department of Food Science, University of Otago, PO Box 56, Dunedin 9054, New 
      Zealand.
FAU - Oey, I
AU  - Oey I
AD  - Department of Food Science, University of Otago, PO Box 56, Dunedin 9054, New 
      Zealand.
FAU - Jowett, Tim
AU  - Jowett T
AD  - Department of Mathematics and Statistics, University of Otago, PO Box 56, Dunedin 
      9054, New Zealand.
FAU - Bremer, P
AU  - Bremer P
AD  - Department of Food Science, University of Otago, PO Box 56, Dunedin 9054, New 
      Zealand. Electronic address: phil.bremer@otago.ac.nz.
LA  - eng
PT  - Journal Article
DEP - 20160608
PL  - Netherlands
TA  - Int J Food Microbiol
JT  - International journal of food microbiology
JID - 8412849
RN  - 451W47IQ8X (Sodium Chloride)
SB  - IM
MH  - Colony Count, Microbial
MH  - Electricity
MH  - Hot Temperature
MH  - Microbial Viability
MH  - Saccharomyces cerevisiae/chemistry/*growth & development/metabolism
MH  - Sodium Chloride/metabolism
OTO - NOTNLM
OT  - Pulsed electric field
OT  - Saccharomyces cerevisiae
OT  - Selective agents, sodium chloride
OT  - Sub-lethal injury quantification
OT  - Thermal treatment
EDAT- 2016/06/28 06:00
MHDA- 2017/03/23 06:00
CRDT- 2016/06/26 06:00
PHST- 2016/02/01 00:00 [received]
PHST- 2016/04/12 00:00 [revised]
PHST- 2016/06/06 00:00 [accepted]
PHST- 2016/06/26 06:00 [entrez]
PHST- 2016/06/28 06:00 [pubmed]
PHST- 2017/03/23 06:00 [medline]
AID - S0168-1605(16)30301-4 [pii]
AID - 10.1016/j.ijfoodmicro.2016.06.008 [doi]
PST - ppublish
SO  - Int J Food Microbiol. 2016 Sep 16;233:73-80. doi: 
      10.1016/j.ijfoodmicro.2016.06.008. Epub 2016 Jun 8.