Thomas MILHOUA

Study Engineer

milhoua@airqualityprocess.com

Cell:+33 6 30 94 02 74

Séverine DOLCI

Sales Manager

dolci@airqualityprocess.com

Cell:+33 6 08 41 57 71

IDENTITY

French company – social capital 1.500.000€

Own study offfice + R&D department + Trial Room

SPECIALTY

Multi safety air conditioning for over 20 years :

all cheeses all rooms from production till packaging

REFERENCES

over 40 complete plants and 1200 ripening rooms running worldwide over 90% activity in cheese dairies

ONE SPECIALIZATION :

THE CHEESE DAIRIES !

SUMMARY

1. Hygiene

a. Sources and vectors of contamination

b. Principles of Air Flow Management

c. Requirements for process rooms and ripening rooms

2. Cheese aging cycle: interactions between the air & the cheese

a. Temperature b. Hygrometry c. Ventilation d. Water losses control e. Air diffusion f. Fresh air g. Ammonia

3. Aging room loading

4. Conclusion, open questions

1. HYGIENE

ANALYSIS OF SOURCES AND

VECTORS OF CONTAMINATION Sources and vectors

of contamination Origin A Few Recommendations

AIR (vector)

• Physical and biological pollutants • Water in form of thin droplets •Air inlets not controlled •Elements that retain particles inside air-coolers / air-conditioners

•Air flow management •Separation of fresh air and recycled air in hot and humid rooms •Drying of the atmosphere after washing •Textile ducts (easily washable) favored •Favor air coolers/ conditioners entirely cleanable and easily controllable – USDA approval

EMPLOYEES (source and vector)

• Desquamation, eyelash, hair, hands… • Clothes

• Suited clothes protections (hat, jacket) •Boots washing / hand disinfection

FLUIDS (source)

Technical fluids location and material •technical area separate from the cheese flow •pipes , screw… in stainless steel in cheese rooms and corrridors

PREMISES (source)

• Material of surface • Coating • Conception

•Hydrophobic walls, doors and ceilings •Tightness of the ceiling

OTHER EQUIPMENTS (source)

•Cleanability •Fixing •Resistance to corrosion and chemicals

Favour conceptions in accordance with USDA recommandation : limitation of corners, elements of retention of particles

WORK PROCESS (source and vector)

• Flow of employees • Work organisation • Cleaning / desinfection •Waste location

•Avoid flows of people from dirty areas to clean areas •Cleaning procedures •Changing room

PRODUCTS (source and vector)

• Flow •Packaging, cardboard dust

•Separation of naked and packed products •Location of cardboards apart from naked products

6

AIR FLOW MANAGEMENT

Principle: create an air flow from the very sensitive areas to the less sensitive areas

The air from the « dirty » area must not

go back toward the « clean » area

THE AIR FLOW MANAGEMENT

PRINCIPLE

DIAGNOSTIC or STUDY

To identify possible sources and vectors of contaminations

CLASSIFICATION OF ZONES

From the row ingredient to the final packed product

FORWARD FLOW ORGANIZATION

Air transfer from the most sensitive areas to the less sensitive

MASTER PLAN AND RECOMMENDATIONS

8

PROCESS ROOMS

Cheese production room

Temperature of the room : 20 à 30°C

according to the cheeses

Basins, open tanks, tables covered

with milk or warm curd (about 33°C) :

continuous evaporation

Constraints

This is a room very sensitive to

contaminations

The room is washed after each

production from floor to ceiling

The humidity is very high

Fresh air & Recycling unit:

To be avoided in hot and humid atmosphere

• Recycling of damp and corrosive air in the air handling unit

• filters: numerous filter cells, premature clogging, water condensation in filters, risk of microbial growth in the filters and battery

• coils: dirtying and decreasing of the global performances

• if non stainless steel elements: corrosion that lower the shelf life

• Rigid recovery ducts: hard to clean and to access for control

• Big units, huge fans with high electrical consumption

PROCESS ROOMS

Permanent ultra-filtrated air introduction: •limited to overpressure (small unit), •compensates for contaminated air extractions, •contributes to the walls drying,

Individualized air treatment through air-conditioner

inside the room •allows to reach thermal balance, •High drying in cleaning phase for a quick return to production •cleanability 100% by CIP •no humidity recycling into filters •small fan with low power motor

PROCESS ROOMS

Separation of fresh air and air recycling:

Perfectly suited to hot and humid atmosphere

Vicious air exhausted at the source

PROCESS ROOM

WASHING

ROOM

11

SEPARATION OF FRESH AND RECYCLED AIR

- Independant, safe and permanent air flow management

- No humid air recyling in AHU No particle retention in the filters leading to

risks of contamination

- Stop of the Air Handling Unit for a very limited maintenance

- High drying power in washing stages

- Lower running costs (filters and energy) with very low power motors of the

air-conditioners

PROCESS ROOMS

12

AGING ROOMS

Conditions depending on the type of cheeses

Possibility to have mono-function or mixed rooms

(drying at heart / ripening / drying on surface)

Requirements

Hygiene

Controled temperature (cooling/heating)

Controled hygrometry (humidifying/dehumidifying)

Homogenous diffusion

Ultra-filtrated fresh air for the oxygenation of the cheeses

and ammonia dilution

2. THE INTERACTIONS

BETWEEN AIR AND CHEESE

IN AGING ROOMS

Cheese is

a unique exchanger!

14

CHEESE BEHAVIOR

AIR :

Temperature,

Relative hygrometry,

Velocity,

CHEESE:

Temperature,

Dry matter,

Activity,

INTERACTION CHEESE / AIR

It breathes by exchanging with ambient air: Air Water Oxygen Carbon dioxide Other gas (such as ammonia)

16

TEMPERATURE

It breathes and sweats

more if it’s hot!

17

TEMPERATURE

Cheese activity is

decreasing when

it’s cold…

And so are the exchanges

with the air…

18

RELATIVE HYGROMETRY

AND CONDENSATION

Raise of the temperature = Raise of the air capacity to be loaded with water

Dew point

Cooling = Reduction of the air capacity to be loaded with water

+ Condensation from saturation point (dew point)

34°F 100%

+ liquid water

50°F 100% 59°F 72% 77°F 39% 95°F 21%

19

HYGROMETRY

Dry Air Air loaded with

humidity and gas

The dryer is the air

compared to the cheese,

the more important is

the evaporation effect

VENTILATION

Drying on surface or at heart ?

Exchanges and drying

are favored by

a strong ventilation

VENTILATION

9650

1000

3050

600

Suited textile ducts allow to control the air speeds required (from static to more ventilated)

Depending on the cheese / room function / supports…

direct diffusion leads to high speeds on cheeses

22

PARAMETERS INFLUENCING

WATER LOSSES

A good insulation to limit the impact of outside air

conditions and heterogeneity

at walls/ceiling Internal Walls: K = 0.25 W/m ²/°C 0.044 Btu/hr.ft².F

External Walls: K = 0.20 W/m ²/°C 0.035 Btu/hr.ft².F

Ceiling: K = 0.17 W/m ²/°C 0.030 Btu/hr.ft².F

Heat emission to be limited:

lights max 5W/m² = 1.6 Btu/(h.ft²)

people

machines Stabilize the ambiance: Limit door opening

The cheese

breathing

increases with

the type of

cheese and

temperature

23

LOW DELTA AIR/WATER

•High exchange surfaces + high

efficiency

•Smooth hydraulic regulation

(loop)

LIMITATION OF HEATING

IN THE ROOM Lowest possible power motor of

ventilator

BLOWN AIR at 100% hygrometry

with suited air-ducts

OVERSATURATION OF THE AIR

Nozzle of humidification

RECOVERED AIR

PRECISE

MEASURE OF

HYGROMETRY

PT 100 probes

Ventilated captor

AIR CONDITIONING SIZING TO

LIMIT WATER LOSSES

24

AIR DIFFUSION : FLOOR

AIR-CONDITIONER REQUIRED

Ceiling air cooler =

Heterogeneity Floor air-conditioner

with inductions textile ducts =

High homogeneity between cheeses on the upper and lower stacks

9650

1000

3050

600

Heterogeneous air mixing

Area less treated

AIR DIFFUSION : LOCATION

OF THE UNIT

Hurdles to be crossed:11 Hurdles to be crossed: 10

Air return

Hurdles to be crossed: 21

Longer air recovery with end location

Shorter air recovery with central location

26

INFLUENCE OF GASES

FRESH AIR NH3 DILUTION

State of surface and cheese growth

influenced by the level of O2, CO2 and

NH3 in the air

3. OTHER PARAMETERS

* type of support

PARAMETERS TO CONTROL

* quantity and arrangement of cheeses by support

Aerated cheeses Poor distribution of the air

through cheeses

PARAMETERS TO CONTROL

NEEDS : drying

-important speed

-T° controlled

-HR % medium

new fabrication

humid products

older products during ripening

NEEDS : ripening

-moderate air speed

-T° controlled

-HR % high

* mixing cheese batches implies a compromise of air conditions

as the needs of the cheeses are different

CONCLUSION

1 – Hygiene

3 – Hygrometry

4 – Ventilation

5 – Air diffusion

6 – Fresh air

7 – Ammonia

2 – Temperature • Cheese growth

• Firming

• Drying at heart

• Drying on surface

• Sate of surface

• Cheese quality

• Sanitary safety

• Homogeneity

• O2 Bringing

• NH3 Dilution

• Cheese growth

• State of surface