ICAR AIEEA-PG / PGS Food Plant Sanitation, Cleaning & Pest Management: practice questions

1 · Detergents: chemistry and selection · medium

Which cleaning approach suits polymeric ultrafiltration membranes that tolerate only moderate pH and temperature?

1. Hydrochloric acid at high concentration
2. Abrasive scrubbing with nylon pads
3. Enzyme detergents with proteases
4. Concentrated sodium hydroxide at 90 °C

2 · Sanitisers: chlorine, iodophors, quaternary ammonium compounds, peracetic acid and others · medium

What is an advantage of iodophor sanitisers?

1. Their amber colour shows that sanitiser is present
2. They are most effective in alkaline solutions
3. They are fully effective at temperatures above 70 °C
4. They never stain plastics or rubber

3 · Cleaning-in-place: design, cycles and the Sinner circle · medium

Water at 1000 kg/m³ and viscosity 0.001 Pa·s flows at 1.5 m/s in a 50 mm pipe during CIP. What is the Reynolds number?

1. 1 500 000
2. 75 000
3. 75 000 000
4. 750

4 · Cleaning-in-place: design, cycles and the Sinner circle · medium

What is a main advantage of a single-use CIP system over a re-use system?

1. No soil carry-over between circuits
2. Lower consumption of water and chemicals
3. No need to heat the cleaning solutions
4. No need to record temperature and time

5 · Cleaning-out-of-place and manual cleaning · easy

Which items are typically cleaned out of place?

1. Falling-film evaporators in a milk-powder plant
2. Long pipelines and large silo tanks
3. Plate heat exchangers in a milk pasteuriser
4. Small parts such as gaskets, valves and blades

6 · Validation and verification of cleaning: ATP, swabs and allergen tests · medium

Why is a neutralising buffer used to moisten swabs for microbiological verification after sanitising?

1. To make the bacteria grow faster on the swab
2. To stop residual sanitiser killing organisms after sampling
3. To kill Listeria so that it is safe to handle
4. To dissolve protein residues before ATP testing

7 · Validation and verification of cleaning: ATP, swabs and allergen tests · easy

Who should carry out the pre-operational inspection of a cleaned line?

1. The cleaner who did the work, checking alone
2. Any visitor who happens to be present in the plant
3. The pest-control contractor on the next visit
4. A trained person other than the cleaner

8 · Validation and verification of cleaning: ATP, swabs and allergen tests · medium

What does a CIP record of flow, temperature, conductivity and time for each phase provide?

1. Validation that the cycle design is correct
2. Verification that the validated cycle was delivered
3. A substitute for all environmental monitoring
4. A microbiological count of the cleaned line

9 · Biofilm control · medium

Why are cells in a biofilm harder to kill with sanitisers than the same cells in suspension?

1. Biofilm cells are dead and so cannot be killed again
2. Sanitisers work only on Gram-positive bacteria in suspension
3. The matrix shields the cells, which also grow differently
4. Biofilm cells are always spores, which resist all chemicals

10 · Biofilm control · medium

Which organisms form biofilms in the warm sections of milk-powder plants and cause quality problems in powders?

1. Psychrotrophic Pseudomonas in the cold milk silo
2. Lactic acid bacteria from the starter culture room
3. Moulds growing on the outside of the spray dryer
4. Thermophilic spore-formers such as Geobacillus