Meat and Dairy Products Flashcards
How can you extend meat shelf-life?
Fermentation
Canning
smoking
Benefits of fermentation
Extends shelf-life
Stable and highly nutritious
Safe
How does nitrite contribute to fermentation of meat?
Prevents decolorisation
Prevents oxidative rancidity of fats
Suppresses gram -ve flora
How do sugars contribute to fermentation of meat?
Fermentable carbohydrates must be added
Lactic acid lower pH and decreases water binding capacity of protein
Speed of fermentation is affected by type of carbohydrate used
What is ripening?
Protein hydrolysed by microbial protein cases to give amino acids
Gives characteristic aroma
Microbiological Issues with fermentation
Green or black moulds on surface
Surface bacterial slime
souring due to excessive lactic acid
Gassiness due t heterofermmentative lactic acid bacteria
Greening of meat pigment by H2O2 production from lactobacillus viridans
What is canning
Minimum heat process applied to low acid canned foods
Gives 12 decimal reduction of c. botulinum
Why do canned foods spoil?
Underfilling
Improper handling
Poor quality san seam
How does smoking preserve meat?
Wood smoke contain antimicrobial substances:
* Formaldehyde
* Phenols
* Methanol
How does smoking preserve meat?
Wood smoke contain antimicrobial substances:
* Formaldehyde
* Phenols
* Methanol
How is yoghurt made?
Bacterial fermentation of milk
Lactase is converted to lactic acid by bacteria
Milk MUST be free from AB residues
Method of making yoghurt
- Raw milk
- Addition of solids
- Homogenise to reduce size of fat globules
- Hat treatment to destroy pathogens
- Cooling then starter culture
For set yogurt
* Package then incubate
For stirred yoghurt
* Incubate then package - Cool and store
What is rennet?
Enzyme which causes milk coagulation
Microbial problems with cheese
Blowing - production of gases
Mould growth
Bacteriophages attacking starter
