Microbial Spoilage Part 1 Flashcards
(33 cards)
Why are Meat, Poultry and Seafood similar ?
They are muscle foods, rich in nutrients (bacterial substrates) which allows extensive microbial growth and growth of microbial pathogens
In what aspect do Meat, Poultry and Seafood differ?
They have different originial microbiotas, leading to a different succession of microbial spoilage bacteria and also differ in the handling and storage requirements used
Difference between natural and external contamination?
Natural: originating from the animal (gastronintesinal tract, skin, feathers) External: Originating from the processing environments (air, soil, water…)
What is the best bacteria for attaching onto surface meat ?
Pseudomonas
What are the best way to preserve meat?
Have a very clean processing facility + animal carcasses must be washed with water right after slaughter
Biofilms are a major issue in food processing environments, why?
- They can form on almost any surface and can persist for years
- Mono-or-multispecies bacteria can be formed by spoilage or pathogenic bacteria
- Bacteria in biofilms can be 10-to 100-fold more resistant to sanitizers in comparison to planktonic cells
What bacteria dominate in aerobic conditions vs in vacuum-packaged products?
Cold Aerobic = gram - (Enterobacteriacae)
Anaerobic = LAB
Pseudomonas inhibits __________ and promotes _________
Shewanella, Listeria
Pseudomonas utilizes glucose and produces _________ at higher rates than Shewanella
siderophores
Pseudomonas hydrolyzes proteins and provides amino acids to ________
Listeria
What is the energy source of spoilage bacteria?
Glucose
Glucose is more rapidly metabolized by which type of bacteria?
Aerobic bacteria like Pseudomonas, if oxygen is present Pseudomonas predominate in spoilage
After glucose, _________ is used as the primary energy source in aerobic and anaerobic conditions
lactate
After lactate, _______ become the most important source fo energy
amino acids
What is the best way to evaluate the freshness of spoiled meat?
Sensory evaluation by trained experts
what are the 4 ideal spoilage indicator?
1) Be absent or present in very low levels in fresh tissue
2) Be produced by the spoilage microflora
3) Increase with storage time
4) Correlate well with sensory analysis
Meat traceability
Ability to maintain credible custody of the identification of animals and their products from production to retail
Name some common microbes present on fresh red meat
- Gram - rods and micrococci
- Pseudomonas and Enterobacteriacae
- Present in lower populations are LAB, Bacillus, and Clostridium spores
_____________ are the dominating spoilage microorganisms in red meat at cold temperatures, on aerobically stored meat
Pseudomonas spp.
If the meat is immediately vacuum packed _________ bacteria will dominate the population
Gram +
In ground meat the dominant microflora on the exterior are _______ but ______ dominate the interior due to oxygen limitation
Pseudomonas, LAB
Greening of processed meats is associated with ____________
hydrogen peroxide
Dry-cured meats are mostly spoiled by _________ or ________ that tolerate low water activity
yeasts or molds
Processing of poultry, what are the steps?
1) Stunning, killing, bleeding
2) Scalding (immersed in hot water)
3) Picking (feathers are removed)
4) Evisceration (intestinal tract mechanically removed)
5) Chilling (carcasses are chilled to reduce microbial growth)
