Food tech 1 Flashcards
What is food technology?
Study of how different foods can be used/ made into food products from production to consumption
What does food chain management include?
- Involves the management of all activities involved in the production, transformation, storage, distribution and the holistic farm to table approach
What is the main aim of food preservation?
To minimise growth of microorganisms during the storage period. increase shelf life.
What is food processing?
Methods used to turn raw materials into food
What is the role of the vet in food tech?
- Inspection of animal origin food establishments
- Microbial testing
- Legislation
What is the D value?
- Decimal reduction time
- Time taken for the population to pass through a log cycle (90% of the population is killed) at a certain temperature
- D121 (time required to kill 90% of a population of microorganisms at 121 degrees
What reduction in the original population do the different D values result in?
- Thermal processing of 1D causes a 90% reduction of the original population.
- Thermal processing of 2D causes a 99% reduction of the original population.
- Thermal processing of 3D causes a 99.9% reduction of the original population.
- Thermal processing of 4D causes a 99.99% reduction of the original population.
What is the Z value?
-The temperature change that is needed to change the D value by a factor of 10
Which gas is most important at controlling microorgansims in food?
Carbon dioxide
used in MAP
Other than carbon dioxide which atmopheric gas has antimicrobial properties?
Ozone
can cause rancidity on high lipid content food
What counts as a spoiled food?
A food that is unacceptable to a consumer- smell, taste, aesthetics, texture or prescence of foreign bodies
What are organoleptic changes?
Brought about by the growth of microorganisms.
What causes chemical changes?
Chemical oxidation of fats producing rancidity
browning of fruits in contact with the air
What is formed by the oxidation of myoglobin?
Metmyoglobin (brown in colour): meat is rejected as spoiled.
(OXYGENATION forms MbO2 which is bright red)
What type of meat is used in fermented sausages?
- Normally pork/ beef
What does the addition of nitrate do to fermented sausages?
- Suppresses gram neg flora
- Promotes growth of streptococci, micrococci, pediococci and lactobacilli that occur normally in meat in low numbers
(Nitrite: Prevents decolourisation of the meat
and prevents oxidative rancidity)
What is the pH of fermented sausages?
about 4.8 due to fermentable carbs producing lactic acid
What determines the speed of fermentation?
The level of carbohydrate used
What organisms are used in starter cultures?
- Lactobacillus plantarum
- Pediococcus acidilacti
- Yeasts
What is involved in the ripening of fermented sausages?
-Protein hydrolysed by microbial proteinases = Aa and other breakdown products
How are the microbiological problems of fermented sausages solved?
Lactic acid to lower pH and salt/ drying to lower water activity
What can spoilage of canned foods be caused by?
- Underfilling
- Quality of the can seam
- Improper handling
- Poor hygiene
What antimicrobial properties are found in wood smoke ?
Formaldehyde
Phenols
Methanol
What are the microbial problems in cheese?
- Blowing (early due to coliforms, late due to gas producing Clostridia)
- Mould growth
- Bacteriophages attacking starter
Which raw foods would you be concerned about Campylobacter jejuni in?
Poultry
Milk
Which raw foods can be contaminated with C. botulinum?
- Vegetables
- Fish
- Peanuts
- Hazelnuts
- Honey
What bacterial pathogen is a concern in Shellfish?
Vibrio parahaemolyticus
What food types can E.Coli contaminate?
- Red meat
- Fruit
- Salad vegetables
- Milk/ milk products
What hygiene monitoring methods are used in food hygiene?
- Swabs
- Solid/ liquids: soil, rinse water
- Personnel: hand swabbing, hand rinsing
- Air: exposure plates
What does the food hygiene industry use microbiological criteria for?
In purchase agreements
What parameters are measured when evaluating the shelf life on a product?
- Deterioration in specific organoleptic qualities
- Microbial growth
