Meat Products Flashcards
How can meat fermentations be started?
- natural fermentation
- back inoculation
- starter culture
T or F: LAB are major components of the microflora of fresh meats
F; minor but when meat is stored in anaerobic conditions the resulting microenvironment facilitates their growth
dry semi dry sausage characteristics
- addition of salt
- fermentation by indigeneous LAB
- indigenous yeasts
- rapid drying conditions of the mediterranean
process conditions of non-refrigerated semidry, shelf-stable sausages
- fermented to pH 4.5 or lower
- must be intact
- internal brine less than 5%
- cured with nitrite
- smoked with wood
what are the basic steps involved in the manufacturing of semidry sausage?
- reduce particle size
- incorporate salt and nitrate, glucose, spices, seasonings and specific starter culture
- uniformly blend all ingredients
- vacuum stuff the meal into a casing to minimize the oxygen
- incubate at or near the starter cultures opt growth temp until a specific pH end point is achieved to inactivate starter culutre and ensure pathogen destruction
- cry-aging
factors that affect final product of meat
bacterial contamination by gram negative bacteria, proteolytic degradation that produce rotten egg smell
describe the microbial ecology of meats
- staphyloccocacae and micrococcacea
- staphylocci reduce nitrate to nitrite and generate nitric oxide which reacts to myoglobin to produce the characteristic cured colour of fermented
3. some LAB not desired
what are the LAB not desired in meats and why? (LV, LB+LM, B)
- lactobacillus viridescens causes greening –> H2O2
- lactobacillus brevis and Leconostoc mesenteroides can produce co2, resulting in gas pockets
- brochotrix –> unpleasant souring
T or F: Fermented meat products rely on heat to destroy pathogenic microorganisms?
False reduction of aw, salt and pH
explain the general process of making fish sauce (process, days etc)
- fish is layered with salt in concrete vats at 3:1 sealing the vats and allowing supernatant to develop.
at 0-25 days: salt penetrates fish tissue by osmosis, proteases increase the soluble protein content of the liquor but this eventually stops due to buildup of amino acids. facultative anaerobes
80-120 days: protein rich liquid develops through autolysis
140-200 days: fish tissue –> nitrogen containing liquid. microbes = bacillus sp.
explain the process of making fish paste?
mixing fish with salt (3:1) and then placing in vats to ferment. proteolytic enzymes from visceral tissue and to some extent from bacteria break down fish tissue into pasty consistency.
pickle –> liquid exudate due to osmotic differential
no more pickle = fish paste ready
what is feseekh? what are issues associated with it?
traditional egyption dish where mullet fish is left to dry in the sun and then
starter cultures in meat must be____, why?
homofermentative to produce enough acid rapidly, grow in 6% salt and have the capacity to enhance flavour without producing slimes
first commercially available meat starter culture? provide its characteristics
Pediococcus acidilactici, it survives lypholization, produces lactic acid, higher optimal growth temp and salt tolerant
Explain the role of starter cultures in the color of fermented meat products (pink, brown and red)
staphylocci and kocuria –> reduce nitrate/nitrite (pink)
increased consumption of oxygen , reduce tension, physical barrier metmyoglobin, continued consumption of O2 metmyoglobin gets reduced to myoglobin
