EXERCISE 3 Flashcards
T/F meat of animals is mildly sterile
T
possible sources of meat contaminants
slaughter, dressing, tranport, storage conditions, external body surfaces, environment
Practices that lead to foodborne outbreaks:
- inadequate refrigeration of meat
- food is prepared too long
- Inadequate cooking or heat processing
- Infected persons in food preparation
Pathogens that cause foodborne outbreaks
psychotropes
give examples of psychotropes
Pseudomonas, Clostridium
heat-stable bacteria
c. perfringens
temperature danger zones
7-60 c
Determinants of microbial load:
ORIGIN AND SANITATION PROCEDURE
importance of examination of meat
assess freshness and quality
determine shelf-life
Easiest method to assess acceptability and wholesomeness of meat
organoleptic exam
Factors affecting the differences of meat of different animals
age, sex, breed, health conditions and feeding
signs of spoilage
- Slime formation
- Discoloration
- Off-flavors
- Off-odors
- Fat rancidity
odor of cattle meat
milk-like
different meat colors
red-brown, red-brown, dark red -brown, pale red, pale red, white-pink
different fat color
light yellow, white to yellow, goldne yellow, white white, yellow
May be done on suspect meat from antemortem inspection and endline products
Microbiological Examination
Microbio exam of meat methods
- Direct Microscopy
- SPC
- Qualitative Examination
SPC limitation
Cannot differentiate pathogenic microorganism, preliminary count
BAP
Enrichment and differential medium for fastidious bacteria
what could be added to grow strep on BAP
crystal violet
what could be added to grow anaerobes in BAP
kanamycin, neomycin
why does BAP have 5% sheep blood
to visualize hemolysis
Selective and differential medium for non-fastidious, G (-) bacilli
MCA
components of MCA
utrient for non-lactose fermenting bacteria
Lactose monohydrate: source of nutrient for lactose fermenting bacteria
Bile salts and CV: inhibit G+ bacteria
NaCl: buffer
Neutral red: pH indicator
Acidic: pink to red
Agar: solidifying agent
Crystal violet
Distilled water
source of nutrient for non-lactose fermenting bacteria
Peptone and Proteose
source of nutrient for lactose fermenting bacteria
Lactose monohydrate
component which inhibits G+ bacteria
Bile salts and CV
pH indicator of MCA
NEUTRAL RED
Normal pH of muscle tissue of live animal
7.0-7.2
Effects of ultimate pH on Meat Quality
- Meat Color
Higher pH (alkaline) → darker meat
Less appealing , mukha siyang matagal na - Meat Tenderness
higher pH → more tender muscle
Commonly seen in male animals - Meat Processing
Higher pH → higher water holding capacity
Muscle proteins are destroyed
How do we achieve the ultimate pH?
Glycogen → lactic acid production → low pH
muscle protein denaturation → cessation of
ATP-driven Ca2+ pump in the sarcoplasmic
reticulum → no ATP synthesis during post mortem → slight crossbridge attachment (due to remaining Ca) but no detachment → stiff muscles→ rigor (20-24 hours post-mortem, pH 5.7-6.0 [desirable])
desirable pH after 20-24 hrs post mortem
5.7-6.0
test used to Estimate bleeding time efficiency
Radan’s test
interpret radan’s color results:
clear blue:
cloudy green:
olive green:
yellow:
super green:
Clear, blue – Normal bleeding
Cloudy, green – Incomplete bleeding
Olive green – Unsatisfactory bleeding
If yellow: not properly bled
Super green: seen on cold slaughter
time needed to render carcass from stunning to bleeding
15 sec
Carotene Test
chemical test for differentiation of beef and carabeef
Carotene test uses ____which releases carotene from the cells and ______ for extraction of carotene from the muscle cells
uses potassium hydroxide which releases carotene from the cells and petroleum ether for extraction of carotene from the muscle cells
use of KOH and Petroleum ether in carotene’s test
uses potassium hydroxide which releases carotene from the cells and petroleum ether for extraction of carotene from the muscle cells
may be added to meat to form metmyoglobin.
nitrite
when nitrite is heated it will form?
nitrosyl hemochrome. = PINK COLORATION OF MEAT
