Questions to answer and hand to your demonstrator at the start of week 2 of the can prac class i.e. week 4 of the semester on August 11:
- In relationship to Clostridium botulinum spores, what is meant by a 12D heat process?
- What types or groups of microorganisms would you expect to find if a can has been under-processed. Explain the reason for your answer.
- What is the meaning of leaker spoilage of canned food and how does this occur?
- What types of microorganisms would you expect to isolate from a can if there is leaker spoilage?
- Suggest two sources of organisms that may contribute to leaker spoilage
- What physical tests would you do on the can seam integrity to determine if the can spoilage has been caused by leaker spoilage?
- Controls need to be applied to ensure production of a batch of appertised food (in a glass bottle, can or sealed pouch) is shelf stable and safe for consumption. As a brief summary, control of the following seven (7) steps is important to ensure production of appertised (commercialy sterile) shelf-stable cans.
- Supply of cans from the can manufacturer
- Source, supply and storage of the raw materials
- Preparation of the product going into the can
- Applying the lids
- Retorting the cans
- Cooling the cans
- Storage and distribution of the cans
- Of the steps listed above, state four (4) steps that are the most important to prevent leaker spoilage in a batch of processed cans. Explain why you have chosen each of them.
- Of the steps listed above, state three steps that are the most important in controlling unerprocessing, in a batch of processed cans. Explain why you have chosen each of them.
- Why is Liver broth (covered with a layer of 2% agar ) commonly used as a growth medium, when analysing cans to check for sterility or cause of spoilage?
- Why is Dextrose Tryptone Broth commonly used as a growth medium, when analysing cans to check for sterility or cause of spoilage?
- After inoculation of the food into the above media the tubes are incubate at two temperatures i.e. 300C and 550C. Why are both of these temperatures used?