Industrial toolkit 2 Flashcards
ANtimicrobials and non-thermal processes
Non-thermal processes include?
irradiation, Pulsed electric fields and high hydrostatic pressure
Bacteriaiophage as a processing aid.. a little bit about them.
tip: considered organic
Virus bacteria most abundant organisms - very specific target NO impact on food quality (not spoilage organism!) use 10^8 PFU = 3 log kill. - Phage must contact bacterial cell - dependent on food.
What is bacteriophages used to control in RTE meats?
L. monocytogenes
Irradiation
Used especially in microwaves to excite water molecule to heat up food.
high energy, shorter wavelength
Microwaves (non-ionizing)
Power source is cavity magnetron which dielectric heating and oscillation of water molecules.
Microwaves as thermal treatment
requires water.
pro’s: rapid, borad spectrum of actvity (viruses, mold, yeast, bacteria)
con: thermoydnaimic gradients ( distribution of water not always uniform), dependent on Aw, endospores not killed.
Ultraviolet Radiation ( non-ionizing)
Power source: UV lamp
DNA absorbs UV.
causes DNA damage,
Affect depends on intensity and time.
What is resistant to UV radiation?
Gram negative< gram positive and yeast < endospores < mold spores ««_space;viruses
The ability of these to recover is reverse.
What is hte pro and con of UV radiation?
Con:limited penetration (smooth surface), and pro is surfaces of foods and clear juices.
Ionizing radiation what is it?
Ejecting e- out of compound ( removes e- from atom to form ions)
- Distribution of atomic nucleus requred to be radioactive.
Uses x-rays, gamma rays, beta-particles
high frequency, high energy radiation
what is the positives of using ionizing radiation?
Control and near-sterility of bacteria, yeasts, moulds, endospores and viruses.
What are the three forms of ionizing radiation used?
B-particles, x-rays, gamma rays
Describe b-particles
High energy e-, stream of electrons emitted, little control on dosage, and some concern about radioactive food.
describe x-rays
produced from high voltage equiptment
Describe gamma rays
radioactive source C0^60 or Cs^137,
Cheapest form, uses atomic waste product, dispoal issues and can use electron beam accelerators.
Three forms of processes of ionization radiation.
- Radurization
- Radicidation
- Radappertization
Describe Radurization
Lose dose, considered soft pastuerization, QUALITY enhancement, and reduces spoilage orgnisms
Describe Radicidation
Equivalent to pasteurixation, specifically refers to REDUCTION of pathogens.
Describe Radappertization
Equivalent to sterilization, much higher dose, and not applied to food ( everything dead!)
Cons of ionizing radiation
consumer resistance–> radioactive food.
dispoal of radioiostopes, SIDE EFFECTS: lipid oxidation (rancidity) (as increase dose, increase problem).
- Some food can be frozen prior to irradiation to inhibit sensory property changes.
What doses of irradiation do you use on fresh foods vs. frozen?
fresh: 1.5-4.5Kgy
frozen: 2-7 kGy
What is cold pasteurization?
Use electron beam. (same outcome as gamma irradiation)
- limited ability to penetrate surface.
3. 5cm in water, and products such as meat must be thin.
Cold pasteurization effects on microorganisms
Product and dose dependent.
3 -6 log reudcition in E. coli O157:H7 in beef.
Reduction of other pathogens.
Salmonella spp., Yersinia enterocolitica, Campylobacter.
LITTLE IMPACT on spore-forming bacteria.
Economic benifit?
Reduction in public health costs associated with foodborne diseases.
- Decrease cost in waste reduction and lawyers.
extends storage life.
