fermented meat products

Question 1

What are fermented meats?

Answer 1

meat products that are incoulated for contamination control and to ensure sufficient control of microbial activity

Question 2

what starter cultures are most often used in meat fermentation?

Answer 2

LAB

Question 3

what are the three ways meat fermentation can be started?

Answer 3

1. natural fermentation
2. back inoculation
3. starter culture

Question 4

what is back inoculation in meat fermentation?

Answer 4

inoculating new meat with a portion of a previous batch

Question 5

how is starter culture added in meat fermentation?

Answer 5

inoculating meat with frozen or freeze dried

Question 6

should the starter cultures in meat fermentation be hetero or homofermentative?

Answer 6

Homofermentative- has to produce enough acid to rapidly lower the pH, grow in 6% salt, and have the capacity to enhance the flavor of the meat without producing slimes

Question 7

what are pediococcus acidilactici characteristics?

Answer 7

1. survives lyophilization
2. rapidly produces lactic acid
3. has a higher optimal growth temperature than lactobacillus sp.
4. is salt tolerant up to 6.5%

Question 8

what is the starter culture that is typically used for dry and semidry sausage?

Answer 8

Lb. plantarum either with or without P. acidilactici

Question 9

how rapidly can meat starter cultures lower pH in a meat product?

Answer 9

from 5.6 to 4.8 in 8 hours

Question 10

what bacteria are used to reduce nitrate/nitrite to nitric oxide

Answer 10

staphylococci and kocuria

Question 11

what enzymes are involved in reducing nitrite-nitrate to nitric oxide?

Answer 11

nitrate/nitrite reductase

Question 12

what attributes to the red color in meat?

Answer 12

consumption of oxygen by growing facultative aerobes

Question 13

what protein contributes to browning in meat?

Answer 13

metmyoglobin (oxidized form of myoglobin, a kind of hemeprotein)

Question 14

What are bacteriocins?

Answer 14

antimicrobial peptides that either kill or inhibit the growth of certain gram-positive bacteria

Question 15

why are bacteriocins added to processed meats?

Answer 15

if there is no heat treatment, bacteriocins are added and do what heat application would do. ameliorates safety concerns

Question 16

what are bacteriocins considered in the meat industry?

Answer 16

natural food preservatives

Question 17

what species of LAB produce bacteriocins?

Answer 17

lactobacillus

Question 18

advantages of using cultures with bacteriocins?

Answer 18

1. antimicrobial activity against pathogens and spoilage bacteria
2. increased shelf life
3. reduced rate of meat tissue degradation

Question 19

what are the two largest categories of fermented meat products?

Answer 19

dry and semidry sausages

Question 20

where do dry and semidry sausages originate from?

Answer 20

the mediterranean

Question 21

what contributes to taste and sensory characteristics in dry and semidry sausages?

Answer 21

1. addition of salt
2. fermentation by indigenous LAB
3. indigenous yeasts
4. rapid drying conditions of the mediterranean

Question 22

what is the process in meat fermentation to favor optimal growth of LAB

Answer 22

heavily seasoned and stuffed into anaerobic sausage casings

Question 23

what compounds preserve sausage products?

Answer 23

1. lactic acid
2. organic acid
3. alcohols

Question 24

when are northern European sausages mad?

Answer 24

in the winter and stored until summer, hence the name summer sausage

Question 25

what is MPR?

Answer 25

moisture-to-protein ratios

Question 26

what are the compositional characteristics of dry and semi-dry sausages?

Answer 26

1. MPR 2. pH limits 3. ingredients

Question 27

what are the regulations for non-commercially sterilized semidry sausages?

Answer 27

1. fermented to a pH of 4.5 or lower 2. must be intact, or vacuum packed if sliced 3. have an internal brine concentration no less than 5% 4. cured with nitrite 5. be smoked with wood

Question 28

what are the manufacturing procedures for semidry sausages?

Answer 28

1. reduce particle size of high-quality raw meat 2. add salt, spices, nitrite 3. uniformly blend all ingredients 4. vacuum stuff the meat into semipermeable casing to minimize oxygen 5. incubate at starter cultures optimal growth temperature until specific pH is reached 6. add heat to inactivate starter culture and ensure pathogen destruction 7. dry to the required MPR

Question 29

what are the factors that affect the final product of semidry sausages?

Answer 29

Raw meat tissues

Question 30

why are raw meat tissues a factor affecting the end product?

Answer 30

they are easily contaminated during the slaughter process because most bacteria come from the hide, skin, or intestinal contents

Question 31

what bacteria are mainly responsible for contamination of raw meat tissues?

Answer 31

gram-negative proteolytic bacteria

Question 32

what are the undesired species of LAB in fermented meats?

Answer 32

1. lactobacillus viridescens - cause greening due to production of hydrogen peroxide 2. lactobacillus brevis and leuconostoc mesenteroides - produce CO2 creating gas pockets 3. brochothrix - cause unpleasant souring

Question 33

what do non-heated products rely on to control pathogens?

Answer 33

reductions in water activity

Question 34

what are the organisms of greatest concern in fermented meats?

Answer 34

1. staphylococcus aureus 2. E. coli 3. salmonella 4. listeria monocytogenes 5. campylobacter 6. trichinella spiralis

Question 35

how are fish sauces made?

Answer 35

predominantly derived from the pressing or decanting of fish that have been fermented from 9 months to a year. fish are layered with salt in concrete vats at a 3:1 ratio (fish to salt), sealing the vats, and allowing a supernatant to develop. the liquid is then carefully removed

Question 36

what does the supernatant that is formed from the fish, contain?

Answer 36

peptides, amino acids, ammonia, and volatile fatty acids

Question 37

how are fish sauces enhanced?

Answer 37

by adding caramel, caramelized sugar, molasses, roasted corn, or roasted barley to enhance the color

Question 38

where do the aroma and flavor of fish sauces come from?

Answer 38

enzymatic activity, oxidation during fermentation, the production of volatile fatty acids, pH, fish composition, and fermentation temperature

Question 39

timeline of fish sauce production?

Answer 39

0-25 days: - salt penetrates fish tissues by osmosis - proteases increase soluble protein content of the liquor, but stops once there's a buildup of amino acids - bacterial populations increase to a high concentration 80-120 days: - a protein rich liquid develops through autolysis 140-200 days: - fish tissue is converted to a nitrogen containing liquid - bacterial population decreases, most microbes present at this point are Bacillus sp.

Question 40

what are fish pastes?

Answer 40

pastes that consist of eviscerated whole or ground fish, shrimp, plankton, or squid with a fish to salt ratio of 3:1 which are then placed in vats to ferment. proteolytic enzymes break down the fish tissue until it has a pasty consistency

Question 41

what is pickle?

Answer 41

the liquid exudate from the fish paste fermentation, which forms as a result of the osmotic differential of the brine solution. when the pickle stops forming the fish paste is ready for consumption

Question 42

what kind of aroma does fish paste have?

Answer 42

salty, cheese like aroma

Question 43

what is Feseekh?

Answer 43

a traditional Egyptian dish prepared by leaving an intact mullet fish to dry out in the sun, followed by 45 days of fermentation in a vat of brine. caused an outbreak due to botulism

Question 44

why is there such a high risk for botulism in un-eviscerated fermented fish products?

Answer 44

it's hard for the added salt to reach the viscera where spores of C. botulinum form