Procedures guidelines guideline for assessing the appropriate cleaning intervals for tetra therm aseptic sterilisers

Cleaning-efficiency depends on several factors Quality of raw product air content, microbial enzymes, undissolved ingredients, salt content Stability Type and configuration of equipment

FSQ-588012-0101

Table of contents

Introduction 3

Cleaning-efficiency depends on several factors 3

Checklist for determining cleaning intervals 3

Some commonly encountered terms 4

Aseptic Intermediate Cleaning 4

Final Cleaning In Place 5

Records 6

Tubular Heat Exchangers (TTA Flex, TTA Primo) 7

General guidelines 7

Practical approach 8

Plate Heat Exchangers (TTA Maxi) 9

General guidelines 9

Practical approach 10

Direct steam injection (TTA VTIS, TTA PLUS ll) 11

General guidelines 11

Practical approach 12

Appendix 13

Checklists 13

Cleaning-efficiency depends on several factors

Quality of raw product (air content,

microbial enzymes, undissolved

ingredients, salt content)

Stability

Type and configuration of equipment Running time restriction

Type of product Type of deposits (protein / fat / minerals)

Running time before cleaning Thickness of deposits

Cleaning solution additives Type of alkaline and acid

Concentration of circulating media

Hardness of water

Cleaning time

Cleaning temperature

Cleaning liquid flow rates

Cleaning result

Because of all these factors it is not possible to state precisely how long a UHT plant can be run before it is necessary to clean

The configuration of the processing equipment will also influence the type of cleaning problems encountered

Checklist for determining cleaning intervals

The following guidelines will help to establish the optimum running time and when ‘Aseptic

Intermediate’ (AIC) and ‘Final Cleaning In Place’ (Final CIP) should be carried out It should be noted that it takes time to find the optimum production-cycle and it requires the co-operation of a motivated team The exercise will have to be repeated until desired result has been achieved

However the benefits will be:

• An increased running time (and therefore a better ratio of production to down time)

• Easier production planning

• A reduced risk of producing defective product

• Increased life time of equipment (especially valid for PHE)

• Decreased consumption of detergents (due to decreased frequency of cleaning)

The checklists found in the appendix will assist you in determining the production hours between cleaning (AIC / Final CIP)

Some commonly encountered terms

The common name for deposits in a product pipe as a result of the differential heating is

‘fouling’.

The heat differential will be the result of the difference of temperature betweenthe heating

medium and the product being processed This is usually referred to as ‘Delta-temperature’ ( ∆-t).

The pressure differential between two points in the process is usually referred to as ‘Delta-pressure’ ( ∆-p).

Aseptic Intermediate Cleaning

An aseptic intermediate clean (AIC) is carried out under production conditions i.e production temperature, flow and pressures are maintained during AIC

The product is purged out with water and this warm rinse is typically followed by a 20 minute alkali step The AIC is then completed by a warm rinse

A typical example of the aseptic intermediate cleaning steps are as follows, although times and other parameters will depend on the particular

installation and verification of the cleaning effectiveness.

n

measured in the holding-cell

Temperature measured at the return

Warm Pre-rinse Water 5 min (reaching prod temp.)

~ 137 ºC ~ 40 ºC Alkali Cleaning NaOH 1.5% - 2,5 % ∗ 20 min ~ 137 ºC ~ 70 oC Warm rinse Water

To electrical conductivity of supply water

10 min ~ 137 ºC

~ 40 ºC

∗ Reference should be made to specialist supplier’s recommendation.

Pure or formulated detergents may be used

Note!

• It is not recommended to carry out more than two (2) Aseptic Intermediate Cleaning cycles within the planned production time

• Normally AIC is not carried out with acid This is because the aggressive nature of the acid at these elevated temperatures will effect the plant

material

Final Cleaning In Place

Depending on the kind of soil every step of a cleaning operation has an optimum operating temperature In general, for cold surfaces, alkali and acid cleaning are performed at 60-80ºC However, in UHT-process equipment, cleaning is performed at a higher temperature than traditional cleaning Typically the alkali clean will be approx 137 ºC and the acid clean

approx 105 ºC, measured in the holding-cell

The product is purged out with water and this warm rinse is typically followed by a 50 minute alkali step After that another warm rinse typically followed by a 30 minute acid step The Final CIP is then completed by a warm rinse plus a final rinse at ambient temperature

A typical example of the final cleaning steps are as follows, although times and other parameters will depend on the particular installation and

verification of the cleaning effectiveness.

n

measured in the holding-cell

Temperature measured at the return

Warm Pre-rinse Water 5 min (reaching prod temp.)

~ 137 ºC ~ 40 ºC Alkali Cleaning NaOH 1.5% - 2,5 % * 50 min ~ 137 ºC ~ 70 oC

Warm rinse Water

To electrical conductivity of supply water

5 min ~ 105 ºC

~ 40 ºC

Acid Cleaning HNO 3 1-1,5 % * 30 min ~ 105 ºC ~ 60 ºC

Warm rinse Water

To electrical conductivity of supply water

5 min ~ 105 ºC

~ 40 ºC

∗ Reference should be made to specialist supplier’s recommendation Pure or

formulated detergents may be used

A Production record is to be filled in by the equipment operator It shall be completed at

least every hour during production

The reporting interval shall be shorter if the raw product quality is poor and the production record shall contain all applicable production and cleaning parameters

A Laboratory record is important to track problems due to dirty equipment This record

shall include information on raw material and finished product quality

The purpose of these records is to be able to trace the effects of the relationship between production activities and the product attributes

Tubular Heat Exchangers (TTA Flex, TTA Primo)

Fouling will occur in:

• The protein stabilisation section where product is usually heated to between

• 85 °C – 100 °C

• In the final heater section where the temperature is at its highest

• In the pre-cooling section where the temperature starts high and is decreased from say,137

°C to 80 °C

The thickening of the deposit is indicated by an increasing ∆t between the temperature at the inlet to the holding cell on product side and temperature at the inlet to heater on hot water side These two are normally indicated by TT 44 (Product temperature) and TT 9 (hot water temperature)

As the thickness of the deposit increases the more difficult it is for the heat in the heating medium to transfer to the product The temperature of the hot water has therefore to increase

to provide enough heat for the product temperature to reach it’s set point, indicated by TT 44 The thickening of the deposit is also indicated by an increasing pressure (normally indicated by

PI 3) before the heating section

This is because the cross sectional area of product pipe decreases as the fouling occurs The product flow will remain unchanged but the velocity will increase

The result of this is that there will be a decreased holding time in the

holding cell.

General guidelines

It is important to note that different filled products have different fouling characteristics during processing This will result in different cleaning

interval requirements All tests should be made using a standard set-up, e.g product, hot water flow, equipment configuration etc.

An acceptable ∆-t can be 5 °C – 10 °C higher than the ∆-t for clean equipment

For example if the temperature at the start of production at TT 44 is 137oC and at TT 9 it is141°C then a rise to say, 146 – 151°C at TT 9 can be accepted before cleaning is

considered necessary

The Pressure difference is dependant on capacity (a low capacity gives a low pressure drop)

A pressure gauge with a low reading span makes reading easier for low pressure drops/low capacities (0-10/25 bars)

An acceptable ∆-p can be 0,5 – 5 bar higher than the ∆-p for clean equipment

For example if the pressure at the start of production is 5 bar at PI 3,

an acceptable rise would be to 5,5 – 10 bar at PI 3 before cleaning is considered necessary

Practical approach

A practical approach to achieve optimum production/cleaning time for

sterilisers equipped with tubular heaters.

• The operator should complete a production record at regular, short intervals

• When the ∆-t and the pressure reach their critical levels and it is time to clean, the

equipment should be stopped

• Open the pipe from outlet of the heating section to holding cell

• Measure and record the thickness of the deposits

• Re-assemble the pipe and run the CIP

• Record CIP parameters during the clean –Temperatures, chemical concentrations, time for each step and flow rates

• After the CIP, re-open, the outlet pipe from the heating section

• Measure and record cleaning result

It should be noted that it may also be difficult to clean the protein stabilisation section and the first part of cooler after the holding cell These should be checked in a similar manner

If the cleaning result is satisfactory then increase the set point for critical values of ∆-t and pressure for next production This will effectively increase the production time before the next clean

After the next production repeat the assessment process as described above

Product quality has a significant impact on the running times and it is only possible to increase production time if the product quality is in control and

is consistent.

Plate Heat Exchangers (TTA Maxi)

This equipment is sensitive to fouling in the final heating section where the temperature is high The thickness of deposits is indicated by an increasing ∆-p (pressure difference) between the product before and after the heating section The pressure is normally indicated by PI 3 This happens because the distance between plates decreases as fouling takes place The product flow will remain unchanged but the velocity will increase

The result of this is that there will be a decreased holding time in the

holding cell.

General guidelines

It is important to note that different filled products have different fouling characteristics during processing This will result in different cleaning

interval requirements All tests should be made using a standard set-up, e.g product, hot water flow, equipment configuration etc.

The Pressure difference is dependant on capacity (a low capacity gives a low pressure drop)

As a guide a maximum of 1.5 bar difference would indicate that the plant is ready for cleaning

Practical approach

A practical approach to achieve optimum production/cleaning time for

sterilisers equipped with plate heaters.

• The operator should complete a production record at regular, short intervals

• When the pressure reaches its critical level and it is time to clean, the equipment should be stopped

• Open the pipe from the outlet of the heating section to holding cell It may be necessary to open the complete heating section

• Measure and record the thickness of the deposits

• Re-assemble the equipment and run the CIP

• Record CIP parameters during the clean –Temperatures, chemical concentrations, time for each step and flow rates

• After the CIP, re-open, the plate heat exchanger

• Measure and record cleaning result

Note!

There is risk associated with opening PHE in terms of damage to gaskets and plates This should only be done if considered to be absolutely

necessary.

A comparison of pressures and temperatures between different

productions can be made at start of production.

If the cleaning result is satisfactory then increase the set point for the critical value of pressure for the next production This will effectively increase the production time before the next clean After the next production repeat the assessment process as described above

Product quality has a significant impact on the running times and it is only possible to increase production time if the product quality is in control and

is consistent.

Direct steam injection (TTA VTIS, TTA PLUS ll)

This equipment is sensitive to fouling in the final heating section where the temperature is high

An increasing opening of the steam valve indicates the thickness of deposits

This occurs because of fouling on the steam-injector, the temperature-transmitter

(TT 44), and constant pressure valve (V.30)

The opening of the steam valve is indicated directly on the valve and, if applicable, on

operators display

As fouling takes place, the product flow will remain unchanged but the velocity will increase

The result of this is that there will be a decreased holding time in the

holding cell.

General guidelines

It is important to note that different filled products have different fouling characteristics during processing This will result in different cleaning

interval requirements All tests should be made using a standard set-up, e.g product, hot water flow, equipment configuration etc.

Use the steam valve as the indicator for the commencement of cleaning An acceptable maximum opening of the steam valve is 75% before cleaning needs to be started.

Practical approach

A practical approach to achieve optimum production/cleaning time for

sterilisers equipped with steam injection.

• The operator should complete a production record at regular, short intervals

• When the steam valve reaches its critical level and it is time to clean, the equipment should

be stopped

• Open the pipe from the outlet of the heating section to holding cell Check for fouling of the steam injector Measure and record the thickness of the deposits

• Re-assemble the equipment and run the CIP

• Record CIP parameters during the clean –Temperatures, chemical concentrations, time for each step and flow rates

• After the CIP re-open the equipment

• Measure and record cleaning result

If the cleaning result is satisfactory then increase set point for critical values for opening of the steam valve for next production This will effectively increase the production time before the next clean After the next production repeat the assessment process as described above

Product quality has a significant impact on the running times and it is only possible to increase production time if the product quality is in control and

is consistent.

Checklists