Flashcards in Lecture 10: Non-Thermal Processing Deck (16):
Why do you put water in the high pressure processing(HPP) machine with the product?
Because water will not compress much, allowing for less damage to the food product.
What are four advantages and four disadvantages to HPP?
See slide 10.
What are the three ways HPP injures or kills microorganisms?
1. Denatures enzymes
2. Destroys membranes
3. Denatures DNA (H bonds compromised)
What molecules does radiation specifically target?
DNA. See slide 17 for mechanism.
How does turbidity affect the potency of UV inactivation of microorganisms?
The more turbid a solution the more time it takes for the UV to destroy the microorganisms. See slide 15.
Can you describe compartmentalization, and how it applies to the preservation of butter?
Revisit our "pre-class" story from this lecture if not.
Besides inactivation of microorganisms, what other food industry is using HPP to reduce processing time?
The seafood industry; revisit slide 6 if you don't remember what they are using HPP for!
What terribly important food safety issue does HPP not eliminate?
HPP does not inactivate bacterial spores very well.
What is meant by adiabatic heating?
Temperature increase without the transfer of heat from the outside; do you remember how this is important in HPP? (see slide 10 if not!)
What are the two target organisms of UV processing? What market is making the most use of this technology?
E. coli O157:H7 and Cryptosporidium parvum. The juice industry.
What molecule is targeted by UV treatment?
DNA; do you remember the specific mechanism (see slide 14 if not)
What are four factors affecting the killing efficiency of microorganisms by UV in juice?
See slide 15; can you describe what the "photolyase" mechanism is all about?
What are the three sources that can be used for irradiation of foods?
Revisit slide 16 for a description of these.
What is the order of resistance to irradiation by type of microorganism?
gram negative < gram positive = molds < viruses
Besides simple food preservation and protection against pathogens, what other uses has irradiation found?
Dealing with food quarantine issues, inhibition of sprouting, insect elimination (see slide 19 for details)