Meat Fermentation Flashcards
(39 cards)
What type of fermentation start method is used for meat? Why?
Can use any of the 3 (inoculation, spontaneous, backslopping)
BUT: inoculation is best (safety and quality-wise)
Why does meat and fish spoil quickly?
moist, nutrient rich environment
pathogens/spoilage bacteria from animal/slaughter
What are the main bacteria in meat starter cultures?
LAB
true/false: there are no LAB present naturally on meat.
False: LAB present but in small population (need to boost and create favorable environment
Traditionally fermented meats (no starter culture) are at a greater risk of causing ______ infection.
Staphylococcus
What are the fermentation conditions for meat products?
Anaerobic
Salt 6%
Acidic (from LAB activity)
What are the requirements when choosing a microbe as a starter for meat fermentation?
- homofermentative (make acid fast!)
- survive high salt
- no slime production
- provide flavor enhancement
What was the first microbe used for commercial meat fermentation culture and what are its advantages? What other organism can it be used with?
Pediococcus acidilactici: survive up to 6.5% salt; can be freeze dried, higher optimal growth temp
Can be used with Lb. plantarum
True/False: unfermented fresh meat has a slightly basic pH
False: fresh meat about pH 5.6
In about 8 hours, starter culture can lower the pH of meat from 5.6 to ____.
4.8
What produces the pink color in fermented meat? Is this absolutely necessary?
nitrites/nitrates added
add nitrite/nitrate reducing bacteria to culture
reduced to nitric oxide (pink color)
No; but otherwise will look less appealing (brown)
What microbes can be added to produce nitric oxide?
kocuria, staphylococci, some lactobacilli
Aside from nitrates, what else contributes to the reddish hue of fermented meat?
Activity of aerobic microbes (near surface):
- decrease surface oxygen
- form barrier (prevent oxygen diffusing in)
- reduce METMYOGLOBIN (brown) -> myoglobin (red)
several species of LAB have an advantage that is important to the prevention of pathogens and spoilage in meat. What is it?
Produce bacteriocin: small peptides that kill/inhibit other Gram positive bacteria
Are bacteriocins harmful to humans? What is harmed by them?
No
targets gram positive bacteria (of another species)
The largest category of fermented meat products:
Where did they originate from?
dry/semidry sausages
came from Mediterranean region (dry warm climate)
How are dry/semidry sausages made?
stuff meat mixed with salt/seasoning into casings (anaerobic) -> drying + fermentation
(no smoking needed)
How is preservation achieved in dry/semidry sausage?
rapid drying (moisture loss) fermentation -> organic acids, alcohols, lactic acid (inhibitory substances)
Sausages made in northern Europe were known as ____ sausages. How did they differ from dry sausages?
summer
made in winter
higher water content
smoked
finer texture (finely ground)
True/False: semidry sausages do not require tight regulation because they have been cured with nitrate
False; need to report MPR, pH, salt, ingredients, etc
unless commercially sterilized
True/False: A shelf-stable semidry sausage is NOT permitted to be sold as slices
True; but can be sold as slices if vacuum packed (otherwise no)
What is “MPR?”
moisture to protein ratio
List the steps for manufacturing a semidry sausage: (7)
- grind meat (reduce particle size)
- add salt, nitrate, seasonings, culture
- blend
- vacuum stuff into semipermeable casing
- incubate -> pH endpoint
- (optional): heat - kill pathogen/starter culture
- dry age (remove moisture)
Where does bacterial contamination of meat products come from? What microbes are involved and what do they cause?
animal, intestines, skin (exposed during slaughter)
GRAM NEGATIVE bacteria
spoilage: proteolysis -> rotten egg smell
