FOOD PRESERVATION 2

Question 1

what is pickling

Answer 1

preserves foods through acidification (acidity controls microbial growth)

Question 2

what is used to pickle

Answer 2

vinegar (acetic acid); other wear organic acids, like lactic and citric

Question 3

what are the two steps of canning

Answer 3

preparation + heating

Question 4

what does preparation mean

Answer 4

packing food and liquid into the container

Question 5

describe headspace

Answer 5

small amount of air left at top after canning preparation; required to ensure vacuum seal

Question 6

describe heating

Answer 6

boiling water processing; needed for low-acid foods

Question 7

how does canning destroy and prevent growth of microorganisms

Answer 7

through heating and removal of O, and sometimes addition of acids

Question 8

what are low-acid foods and what are high-acid foods

Answer 8

low acid foods have a pH higher than 4.6
high acid foods have pH lower than 4.6

Question 9

what are the two methods of cold preservation

Answer 9

refrigeration + freezing

Question 10

describe refrigeration

Answer 10

slows down biological, chemical and physical rxns

Question 11

describe freezing

Answer 11

least damaging preservation method in terms of flavor, nutrient content, and texture

Question 12

what does freezsing do to microroganisms

Answer 12

makes water unavailable to microorganisms to grow, but still some O present

Question 13

describe relationship between fat content and shelf life

Answer 13

higher fat content = lower shelf life due to rancidity

Question 14

what are the four problems with frozen foods

Answer 14

freezer burns, cell-rupturing, fluid loss, recrystallization

Question 15

describe freezer burn

Answer 15

caused by moisture loss (via sublimation) resulting in altered texture, appearance, and flavor; due to improper packaging or prolonged freezing

Question 16

describe cell-rupturing

Answer 16

water expands upon freezing; large crytals can rupture food’s cell cells causing inferior texture

Question 17

should foods with higher water content be frozen

Answer 17

no

Question 18

describe fluid loss

Answer 18

frozen meat loses water when thawed, which can result in drier texture

Question 19

describe recrystallization

Answer 19

small ice crystals melt and freeze as larger crystal, which affects texture; occurs with temp. fluctuations; more crystals = worse quality of food

Question 20

describe boiling

Answer 20

10 min of boiling kills/inactivates most microroganisms

Question 21

describe ohmic heating

Answer 21

electrical current passed through food to generate heat to destroy microorganisms; used in juice preservation

Question 22

describe pasteurization

Answer 22

foods heated to specified temp for a certain period of time to destroy microorganisms

Question 23

describe milk pasteurization

Answer 23

145 F for 30 min

Question 24

describe high temp short time pasteurization varaiation

Answer 24

161 F for 15 seconds

Question 25

describe ultra high temp pasteurization variation

Answer 25

temps >280 F for 2 seconds

Question 26

whats irradiation

Answer 26

cold pasteurization; food exposed to ionizing energy source, like gamma rays, X-rays, or electrons

Question 27

does irradiation make food radioactive

Answer 27

no

Question 28

what do free radicals do

Answer 28

damage DNA of microorganisms

Question 29

what is irradiation used in

Answer 29

wheat flour, potatoes, spices, meat, shellfish, poultry, eggs

Question 30

what are some concerns with irradiation

Answer 30

possible nutrient loss, environmental hazards, and free-radical production

Question 31

what are the labeling requirements for irradiation

Answer 31

“treated with radiation”

Question 32

describe pulsed light

Answer 32

food exposed to intense, brief flashes of light

Question 33

what does pulsed light do to bacteria

Answer 33

disrupts bacterial cell membrane, but not those of the surrounding foods
damages bacterial DNA

Question 34

whats high-pressure processing (HPP)

Answer 34

uses high pressure (<50,000 psi for 15 min) to deactivate microorganisms and enzymes responsible for deterioration

Question 35

when is HPP used

Answer 35

for juices, sauces, ready-to-eat meats

Question 36

how are macros, fat-soluble vitamins, and minerals effected by processing

Answer 36

relatively unaffected

Question 37

what vitamins are most susceptible to loss after cooking in liquid

Answer 37

water-soluble vitamins (c and b0

Question 38

is nutrient data for cooked foods limited

Answer 38

yes

Question 39

do unprocessed foods undergo nutrient loss

Answer 39

yes