Topic 2 : Sanitary plant and equipment design

Question 1

Sanitary plant design

What are the 10 key principles in sanitary plant design?

Answer 1

Exterior of plant :

1) Choose an appropriate building site
- barren with no trees (habourage points), bright lights (insect) and pave ground with gravel (prevent rat burrows)

2) Building exterior provide adequate barrier against bioterrorist and pest

Inside the plant :

3) Establishing distinct hygienic zones in the facility → 4 zones

4) Control flow of personnel and materials

• unidirectional flow to ensure no cross contamination

5) Interior space design should promote sanitation

• equipment don’t lean against walls, not touching ceiling or floors for easy cleaning

6) Choose compatible materials for construction of the plant

• floors should be scratch proof, easily cleaned, resistant to corrosion

7) Plan for utilities (water, light) and COP/CIP

Ambient envt :

8) Reduce water accumulation

9) Temperature and humidity control

10) Control of air quality

• air pressure

When building a factory, first pick a clean site and build pest-proof walls. Then design flow zones, plan staff movement, ensure you have all the utilities and ensure the layout of equipment in the plant makes it easy to clean. Then control ambient environment – moisture, temp/humidity and air quality.

Question 2

Sanitary plant design

What are the 4 hygiene zones in a food facility?

Answer 2

1. Non-food production zone (e.g. office)
2. Basic hygiene zone
3. Medium hygiene zone
4. High hygiene zone

Question 2

Sanitary plant design

What occurs in the basic hygiene zone? [3]

Answer 2

• Inflow of raw materials (still in their packaging)
• inflow of workers
• Finished products that are fully sealed to exit the plant.

Question 3

Sanitary plant design

What occurs in the medium hygiene zone?
Is the exposure of product to hazards in the medium hygiene zone problematic?

Answer 3

Raw materials are taken out of packaging and undergo general processing (washing, slicing etc).

No, not problematic, because there are subsequent control steps (to ensure to chemical/microbial/physical hazards) → in high hygiene zone

Note : some plants may not have high hygiene zone for very low risk products

Question 3

Sanitary plant design

What occurs in high hygiene zone? What requirement is there for air pressure and why?

Answer 3

Incoming food product undergoes main microbial hazard reduction steps and other control steps. (biological, chemical, physical hazard)

Need for positive air pressure so that air from high hygiene zone can flow out (not the other way round where air from other zone flow into high hygiene zone), as air needs to be of higher quality to prevent contamination (esp microbial).

Question 4

Sanitary plant design - 2 : Control flow of personnel and materials

Barriers can be set up between hygiene zones to control flow of personnel and materials. What can of barriers can be placed? [3]

Answer 4

1. Handwashing areas
2. Changing areas → especially when going from basic zone to high risk zone!
3. Boot scrubs

Question 5

Sanitary plant design - 3 : reduce water accumulation

How to design the plant floor to reduce water accumulation?

Answer 5

Have appropriate slope with covered drains.

Question 5

Sanitary plant design - 4 : temperature and humidity control

What kind of food products require strict temperature or humidity control? [3]

Answer 5

1. Raw meat (need to be 12-15℃)
2. Dry hygroscopic powder : below 50% RH
3. Ventilation of steam from food processing (e.g. bakery) to reduce humidity

Question 6

Sanitary plant design - 5 : control of air quality

Other than for hygiene control, air quality is important for control of …..?

Answer 6

1. Allergen control → high air quality so that no allergen dust present in air
2. Dust explosion control

Question 7

Sanitary plant design - 5 : control of air quality

In restrooms, should there be positive or negative air pressure?

Answer 7

Negative air pressure = keep contaminants in.

Restroom have lower pressure, so that air from food processing zones will flow into toilet, not air flowing out from toilet)

Negative air pressure = flow of air into the area (from area of higher pressure
Positive air pressure = flow of air out from the area (into area of lower pressure)

Question 8

Sanitary plant design - 7 : building exterior barrier

The building exterior should have barrier against…? [2]

Answer 8

1.Bioterrorist
2.Pest

Question 9

Sanitary plant design - 7 : building exterior barrier

How to guard against bioterrorism? [2]

Answer 9

1. Controlled entry to plant with security, being able to exclude and identify intruders
2. Access control : lock and key to critical areas such as warehouse, air and water supply

Question 10

Sanitary plant design - 7 : building exterior barrier

How to guard against pests ? [3]

Answer 10

1. Gravel path so rats cannot burrow under soil
2. Self-closing barriers at doors
3. Choose a site with barren surroundings
   - No trees / bushes (potential habourage points)
   - Fertilisers may attract pest
   - Lighting at gate may attract insects

Question 10

Sanitary plant design - 8 : interior space plan primites sanitation

Principle 8 : Interior space plan primites sanitation. What does this mean? [3]

Answer 10

Food processing equipment
- should not be placed against walls
- not directly on floor
- not touching the ceiling

Question 11

Sanitary plant design - 10 : plan for utilities and CIP/COP

For utilities such as light, what is the lighting requirement for general working area / close inspection of foods?

Answer 11

General working area has lower lighting requirement (220 lux) than close inspection (540 lux)

Note : dont need memorise numbers

Question 11

Sanitary equipment design

What are the 5 principles of sanitary equipment design?

Answer 11

1) Designed to be cleanable → smooth, non-porous and should be free of crevices and sharp edges

2) Accessible for cleaning → easy to reach

3) Made of compatible materials → corrosion resistant

4) Equipment should be self-draining

5) Hollow areas should be hermatically sealed

Question 12

Sanitary equipment design

3Principle 1 : equipment should be designed to be cleanable. What 4 characteristics should an ideal surface possess?

Answer 12

1. Smooth
2. No pores and cleanable
3. Free of crevices, sharp corners or angles (no cracks or gaps where food material could get stuck)

refer to lect notes pics

Question 12

Sanitary equipment design

Principle 3 : equipment should be made of compatible materials. What kinds of compatible materials?

Answer 12

Corrosion proof materials like stainless steel / aluminium alloys

Question 13

Sanitary equipment design

Principle 5 : hollow areas should be hermetically sealed. Why?

Answer 13

Full airtight seal to prevent food, moistre and bacteria from getting stuck in the hollow area. In addition, these areas are harder to wash.

Question 14

Other storage considerations

What is FIFO and why is it important?

Answer 14

First In, First Out stock rotation ensures older stock is used before newer ones to prevent spoilage.

Question 15

Other storage considerations

What materials should shelves in food storage areas be made of?

Answer 15

Corrosion-proof materials.

Question 16

Other storage considerations

What are key segregation requirements in food storage? [3]

Answer 16

1. Raw vs. finished products
2. Dry vs. moist foods
3. Use rodent-proof containers

Question 17

Multiple Reponse Questions - MRQ

Question 1: Zoning and Facility Layout

Which of the following are features of a high hygiene zone in a food facility?

A) Positive air pressure
B) Use of HEPA filters
C) Location for receiving raw ingredients
D) Product packaging after microbial reduction
E) Sharing entrance with non-food zones

Answer 17

A,B,D

Product should be immediately packaged after microbial production, only after packaging then it goes to basic hygiene zone.

Question 18

Question 2: Drainage and Water Accumulation

Which design considerations help reduce water accumulation in a food plant?
A) Installing open floor drains at corners
B) Sloped floors with central covered drains
C) Using raised platforms for equipment
D) Avoiding pooling of water during cleaning
E) Increasing room humidity to reduce evaporation

Answer 18

B, C, D
- Option E : increasing humidity = more moist = increases contamination risk

Question 19

Question 4: Equipment Sanitary Design ***Which design features improve the cleanability of food equipment?*** A) Sharp internal corners for improved mixing B) Welded, polished joints with smooth surfaces C) Easily accessible parts for cleaning D) Use of hollow legs with unsealed openings E) Gaskets and seals at fastener joints

Answer 19

B, C, E ## Footnote ***Gasket : a mechanical seal which fills the space between two or more mating surfaces***

Question 19

Question 3: Air Quality Management ***Which of the following statements about air control in food facilities are correct?*** A) High hygiene zones should have positive air pressure B) Air always flows from lower pressure to higher pressure C) Restrooms should be maintained under negative pressure D) Dry food processing areas may require dust explosion control E) Air filters are not required if temperature is controlled

Answer 19

A, C, D

Question 19

Question 5: Food Storage Practices ***Which are good practices for food storage in a sanitary plant?*** A) Store food 10 cm above the ground B) Segregate raw and finished products C) Maintain chilled foods at -4°C to 7°C D) Use rodent-proof containers E) Store food directly on tiled floors for cooling

Answer 19

B, C, D

Question 19

***Q6 : Which construction materials are suitable for a food processing facility? (Select all that apply)*** A) Stainless steel AISI 316 B) PU-coated concrete C) Porous ceramic tiles D) Painted plywood E) Epoxy-coated floors

Answer 19

A,C,E ☑ Stainless steel AISI 316 ☑ PU-coated concrete ☑ Epoxy-coated floors

Question 20

***Q7: Which of the following are plant design principles that help prevent cross-contamination? (Select all that apply)*** A) Personnel and product flow separation B) Zone segregation C) Sloped floors and drainage D) Use of food-grade preservatives E) Controlled air flow

Answer 20

A,B,C,E