Injury and Recovery

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Injury and Recovery

• By
• Mr. Thitiwat S. ID. 4527863

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Injury

• Microorganisms subject to a stress condition
  (Heat, Cold, Salt, Detergent, pH and irradiation)
  can be injured. During the injury, the cell may
  appear dead. But in fact the cell may be
  revivable. That is the term of Phoenix
  phenomenon.
• Injury can detected by differential number of CFU
  that are observe on a non-selective and selective
  media.

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What is the Phoenix phenomenon?

• The Phoenix phenomenon is the unexpected
  proliferation of microbiological growth after an
  antimicrobial process (e.g. heat pasteurization).
  ). The process is expected to kill all the
  pathogenic viable cells and significantly reduce
  the numbers of spoilage microbes. That killing
  effect might be erroneously confirmed by standard
  microbiological methods. The growth of
  microorganisms after antimicrobial processing
  continue. The cause is injury repair during an
  extended lag phase.

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Recovery

• Resuscitation of cells sampled from the
  environment and placed in similated natural
  environment setting.
• When the cell's metabolism starts up again, by
  injury repair or by spore germination, the cell
  resumes its metabolically active life.

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Recovery Factors

• Time
• Temperature
• Medium Composition
• pH

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• Extended Lag Phase Increased time for a cell
  or cells to start growing exponentially. The lag
  is caused by injury requiring extra repair time.
• When a cell is injured there is an extended lag
  phase as illustrated  

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The Microbial Growth Curve showing only extended
lag phase and log phase. CFU/ml. 5

x 4

x 3 I
log x 2 I

x 1 I lag Extended lag
x 0 I xxxxxxxxxxxxxxxxxxxxxxxxxxx------
--------------------------0 10 20
30 40 50 60 70 80
90
Time (hours)

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How to study Injury Recovery Mechanisms
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• The basic procedure for studying injury recovery
  mechanism is this First, the minimal inhibitory
  concentration for an inhibitor is determined by
  an experiment. This can be done with many
  inhibitors to get a better feel for what kind of
  injury recovery pathway may be present, if any
  are present at all. One of the first problems is
  to choose the inhibitors and find out where each
  of them affect the Earth-based biology.

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• Some lessons from the Food Industry. Has injury
  has masked viable cells in a false cloak of death
  or are the cells truly dead and permanently
  nonviable. Strategies of food borne
  microbiological pathogens and spoilage organisms
  permit survival after food processing. The cause
  is injury repair during an extended lag phase.
  It is an expensive problem area if a product
  recall must be issued or if consumers become ill.

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Thank you