what’s does the microbiome of milk look like when it comes straight out of the udder?
sterile
what kind of products is aseptic processing especially good for? why?
heat sensitive; it easily accommodates needs for HTST and HT
describe batch processing treatment for milk
pasteurize at 62.5C for 30 mins, then package
describe HTST treatment for milk
71C for 15 seconds, followed by rapid cooling to 2C, then packaging
what equipment is used to pasteurize milk?
plate and frame heat exchanger
describe UHT treatment for milk
> 100C for 1 second by direct steam injection followed by rapid cooling & aseptic packaging
advantages of aseptic processing?
- continuous
- very high and efficient heat transfer rate
- containers don’t interfere with heat transfer
what’s a tetra brick?
folded sterile package made on site from a single roll of laminate (cardboard, aluminum foil, plastic)
what’s an integrated process?
package machines are part of the production line
what’s commonly used to sterilize packages for aseptic packaging?
- UV light
- H2O2
which is more cost effective: tetra brick or cans?
tetra brick
describe refrigeration’s role as a processing aid
- extend shelf life
- allow for proper aging of cheese, beef, and wines
- firm up bread & roasted meats prior to slicing
what’s a eutectic point?
temp where residual water and all solutes co-crystallize
what are some changes that occur during freezing? (5)
- solubility reduction (grainy ice cream)
- protein denaturation (salting out)
- changes in pH
- destruction of sensitive emulsions
- loss of gas solubility
why does water expand when frozen?
hydrogen bonding
what kind of freezing causes more damage?
slow, which forms larger ice crystals
what factors can increase freezing rates?
- thinner packages
- colder temperatures
- increased air flow
