1.
State what is meant by a foodborne pathogen.
[1 mark]
- microbe that causes illness via food
JD SCIENCE
Food microbiology
Indicative marking points. Award marks for equivalent scientific or mathematical wording. Do not issue this sheet with the student worksheet.
2.
State what is meant by a spoilage organism.
[1 mark]
- makes food unacceptable but not always unsafe
3.
State what is meant by the danger zone.
[1 mark]
- 5–63 °C where many bacteria grow fast
4.
State what is meant by water activity.
[1 mark]
- available water for microbes
5.
State what is meant by pH and food.
[1 mark]
- low pH inhibits many pathogens
6.
State what is meant by cross-contamination.
[1 mark]
- transfer of microbes from raw to ready-to-eat
7.
State what is meant by a colony count.
[1 mark]
- cfu per gram or ml
8.
State what is meant by hygiene swabbing.
[1 mark]
- checks cleaning
9.
State what is meant by shelf-life.
[1 mark]
- time the food stays safe and of quality
10.
State what is meant by pasteurisation.
[1 mark]
- heat process that reduces pathogens
11.
Noah is asked about a foodborne pathogen in a NCFE Food Sciences paper.
(a) [2 marks]
- Salmonella, Listeria, Campylobacter, E. coli
(b) [3 marks]
- zero or very low limits
12.
Noah is asked about a spoilage organism in a NCFE Food Sciences paper.
(a) [2 marks]
- yeasts, moulds, lactic acid bacteria
(b) [3 marks]
- shelf-life testing
13.
Noah is asked about the danger zone in a NCFE Food Sciences paper.
(a) [2 marks]
- keep food out of it
(b) [3 marks]
- chill or hot-hold
14.
Noah is asked about water activity in a NCFE Food Sciences paper.
(a) [2 marks]
- lowered by salt, sugar, drying
(b) [3 marks]
- controls spoilage
15.
Noah is asked about pH and food in a NCFE Food Sciences paper.
(a) [2 marks]
- pickles, yoghurt
(b) [3 marks]
- not a CCP on its own unless validated
16.
Noah is asked about cross-contamination in a NCFE Food Sciences paper.
(a) [2 marks]
- boards, cloths, hands
(b) [3 marks]
- colour-coded equipment
17.
45 colonies from 1 cm³ of a 10⁻³ dilution. cfu/cm³?
[3 marks]
- Final answer: 4.5 × 10⁴
18.
A 25 g sample in 225 cm³ diluent. First dilution factor?
[3 marks]
- Final answer: 10⁻¹
19.
Danger zone width from 5 to 63 °C
[3 marks]
- Final answer: 58 °C
20.
Fridge 4 °C vs room 20 °C. Difference?
[3 marks]
- Final answer: 16 °C
21.
Swabs: 2 of 20 fail. Percentage fail?
[3 marks]
- Final answer: 10%
22.
Generation time 20 min. Generations in 2 h?
[3 marks]
- Final answer: 6
23.
Noah carries out a T-Level occupational task on food microbiology. This is a typical NCFE required-practical style question.
(a) [2 marks]
- Independent: the factor being investigated
- Dependent: the measured result or quality check
(b) [2 marks]
- follow the SOP and keep other variables constant
- so the test is fair / only one variable is changed
(c) [2 marks]
- not recording the batch/lot number or operator ID
24.
Noah carries out writing or following an SOP for food microbiology. This is a typical NCFE required-practical style question.
(a) [2 marks]
- Independent: a step in the method
- Dependent: whether the acceptance criteria are met
(b) [2 marks]
- same calibrated instrument
- so the test is fair / only one variable is changed
(c) [2 marks]
- skipping a verification check
25.
Noah carries out a COSHH / risk-assessment review for food microbiology. This is a typical NCFE required-practical style question.
(a) [2 marks]
- Independent: hazard
- Dependent: control measure effectiveness
(b) [2 marks]
- same PPE and waste route
- so the test is fair / only one variable is changed
(c) [2 marks]
- using expired reagents or the wrong waste stream
26.
Noah carries out data review in a LIMS or quality log for food microbiology. This is a typical NCFE required-practical style question.
(a) [2 marks]
- Independent: sample ID
- Dependent: result vs specification
(b) [2 marks]
- same calculation method
- so the test is fair / only one variable is changed
(c) [2 marks]
- transcription error between the instrument and the LIMS
27.
Compare a foodborne pathogen with water activity.
[4 marks]
- microbe that causes illness via food
- available water for microbes
- state one workplace implication
28.
Compare a spoilage organism with pH and food.
[4 marks]
- makes food unacceptable but not always unsafe
- low pH inhibits many pathogens
- state one workplace implication
29.
Compare the danger zone with cross-contamination.
[4 marks]
- 5–63 °C where many bacteria grow fast
- transfer of microbes from raw to ready-to-eat
- state one workplace implication
30.
Compare water activity with a colony count.
[4 marks]
- available water for microbes
- cfu per gram or ml
- state one workplace implication
31.
Apply your knowledge of a colony count to this situation: serial dilution and plates
[3 marks]
- serial dilution and plates
32.
Apply your knowledge of hygiene swabbing to this situation: pass/fail limits in the SOP
[3 marks]
- pass/fail limits in the SOP