Guidelines for Efficacy Evaluation of On-farm Dairy Cleansers and Sanitisers

Scope

Dairy cleansers and sanitisers are used in milking machinery, tankers and milk factory machinery to remove milk residues and provide a clean surface on which micro-organisms cannot survive or multiply. In on-farm situations dairy cleansers and sanitisers are used in milking machines and milk vats as a key component of the milk hygiene regime. Dairy cleansers for on-farm use are declared to be agricultural chemical products by the Agricultural and Veterinary Code Regulations 1995. As such, these products must be registered by the APVMA before being supplied or used in Australia. Dairy cleansers for use in dairy tankers and factories are regulated separately and fall under the jurisdiction of the National Industrial Chemicals Notification and Assessment Scheme (NICNAS).

Prior to registration, the APVMA must be satisfied that it has the required information relating to the proposed product and that it can be satisfied on a range of criteria including safety, trade and efficacy. The information to be provided with applications is set out in the legislative instrument for application requirements. Technical data may be required to address safety criteria, efficacy criteria and trade criteria. 

This document outlines ways by which the efficacy criteria may be satisfied for dairy cleansers and sanitisers for use on-farm. It is intended to assist chemical companies considering or proposing the registration of new or novel on-farm dairy cleansers and sanitisers by identifying ways by which efficacy may be demonstrated.

These guidelines have been developed in conjunction with Dairy Australia. Dairy Australia funded and led the project to initiate the development of these guidelines.

Demonstration of efficacy of dairy cleansers and sanitisers

The types of information expected to satisfy the efficacy criteria reflect the degree of novelty of a proposed product. Details regarding limits on use of information can be accessed here

Efficacy can be established in the following ways:

  • Reliance on a reference product
  • Bioequivalence data and/or scientific argument to establish bioequivalence
  • Stand-alone data

Table 1 provides a guide to the type of efficacy data considered acceptable for a range of situations and includes details of how data may be generated.

Type of application How efficacy is to be established

Data from laboratory efficacy tests*

Data from in situ tests^
Available chlorine Biocidal activity Cleaning activity
Cleansers Sanitisers Cleansers Sanitisers Cleansers Sanitisers Cleansers Sanitisers
Product closely similar to a reference product  Rely on satisfaction with Reference product No No No No No No No No

Product similar to a reference product

Product containing the same active constituent/s at the same or similar concentration/s with the same or similar use pattern to a reference product (there must be no limitations on the use of any data relating to the reference product

Bio-equivalence

No Yes if chlorinated compound No Yes for sanitisers other than chlorine sanitisers Yes No No No

Product with new active constituent

Product with new combination of active constituents

Product with new/novel use pattern

Stand-alone data No Yes if chlorinated compound No Yes for sanitisers other than chlorine sanitisers Yes No Yes Yes

+ See Laboratory efficacy tests for details.
^ See In situ (trial) efficacy tests for details.

Reliance on a reference product

Schedule 6 (1.2) of the Agricultural and Veterinary Chemicals Code Regulations 1995 defines ‘closely similar’. A determination of close similarity requires a comparison of the formulation (active constituents and other ingredients) of the proposed and the reference product. 

If the proposed and reference products are determined to be closely similar, the APVMA can rely on satisfaction of the efficacy criteria for the reference product to be satisfied of the proposed product. In this case no other information is required to satisfy the efficacy criteria.

Bioequivalence

Schedule 6 (1.3) of the Agricultural and Veterinary Chemicals Code Regulations 1995 defines ‘similar’. 

If the proposed and reference products are determined to be similar the APVMA may accept bioequivalence data and/or scientific argument to demonstrate that the proposed product is equivalent to the reference product. However, if a product is considered similar to a reference product which has protected information, you must provide your own stand-alone data or obtain consent from the authorising party for the APVMA to use it.

Bioequivalence data

Bioequivalence is generally demonstrated through the comparison of an APVMA-registered reference product and the proposed product. Each product is tested using parameters which are relevant to the use pattern described on the label. When designing bioequivalence trials:

  • The reference product(s) should have the same or very similar uses and instructions as presented for the new product
  • The trials should test the products in equivalent situations (e.g. side by side, so that environmental conditions are the same)
  • The trials should be designed to provide data that can undergo appropriate statistical analysis. Experimental designs with large coefficients of variation will show non-significant differences between treatments and will not be accepted as demonstrating bioequivalence between treatments
  • Where the product label includes a number of claims, the trials should include assessment of each of these claims (see stand-alone section below for how to assess claims)
  • Demonstrated bioequivalence might not be sufficient to satisfy the efficacy criteria if both the proposed and reference or comparator products exhibit poor control
  • If an overseas-registered product is used in the bioequivalence study, you will need to demonstrate that the overseas product is the same as an APVMA-registered product.

Provision of scientific argument

The APVMA considers changes to formulations and/or use patterns on a case-by-case basis. Some changes to formulation may require a simple discussion of the properties of each ingredient involved, their purpose in the formulation and why the change should not affect efficacy or the stability of the formulation. Other changes, such as introducing half-strength or double-strength formulations, may be justified by sound scientific argument in lieu of data. For example, if the product label recommends a dilution to ensure that the same amount of active constituent is applied, and similar proportions of the same adjuvants and other critical constituents are present in the diluted form, a scientific argument for bioequivalence may be acceptable.

The provision of chemical data and bridging argument alone is generally not sufficient to demonstrate chemical similarity or bioequivalence if the formulation of the reference product cannot be accessed. This is largely due to the variable reliability of testing methodologies, possible changes in excipients or changed proportions of formulation components which may result from reverse engineering to identify types and concentrations of ingredients.

Stand-alone data

The following sections describe methods considered appropriate to demonstrate the efficacy of on-farm dairy cleansers and sanitisers. The APVMA will consider data generated using alternate methods so long as the data generated support the proposed claims. Justification should be provided as to why the methods described below were not used.

Laboratory efficacy tests

Dairy cleansers

General Cleaning

Methods for determining the efficacy of general dairy cleansers are described in AS 1803-1998 General purpose detergents for use in the dairying industry: Appendix B – Method for Assessing Cleaning Performance1. In general, the method relies on a comparison of the cleaning performance of the proposed product and a reference cleanser (an existing registered product).

Acidic Detergents

Acidic detergents are used to remove 'milkstone', rust and water scale as well as for general cleaning. AS 1389-1997 Acid detergents for use in the dairying industry provides details of how to demonstrate both performance and equivalence for acid cleansers.

Where the label claims that the product is suitable in conditions in which water quality differs to that described in AS 1803-1998 and AS 1389-1997 then additional tests should be performed using water of a quality that reflects the label claim. For example, if the label claims that the cleanser is suitable for all water types (either by a statement on the label, or by omission of such a statement) then tests should be performed using water that represents “worst” and 'normal' case scenarios (e.g. dam/channel water and rain/bore water).

Dairy sanitisers

Chlorinated sanitisers

Efficacy of chlorinated sanitisers should be evaluated using the AOAC Chlorine Available in Disinfectants Method – Germicidal Equivalent Concentration Test (955.16)2, or equivalent. Test results should show concentrations equivalent in activity to 50, 100, and 200 ppm of available chlorine (reference standard sodium hypochlorite).

Non-chlorinated sanitisers

Biocidal efficacy should be evaluated using the AOAC Germicidal and Detergent Sanitizing Action of Disinfectants Method (960.09) against Escherichia coli ATCC No. 11229, as defined in the method or an equivalent method. Acceptable results, as defined by the method, must demonstrate a 99.999% reduction in the number of microorganisms within 30 seconds.

Iodophors are a subset of non-chlorinated sanitisers which when appropriately diluted can be used for sanitising on-farm dairy equipment. This group of sanitisers are based on iodine and may be assessed as outlined above or by the methods outlined in AS 1398-1998 Iodophors for use in the dairying industry which include both available iodine content and bactericidal efficacy.

Where the label claims that the product is suitable in conditions in which water quality differs to that described in AOAC methodologies then additional tests should be performed using water quality that reflects the label claim. For example, if the label claims that the sanitiser is suitable for all water types (either by a statement on the label, or by omission of such a statement) then tests should be performed using water quality that represent “worst” and “normal” case scenarios (eg dam/channel water and rain/bore water).

In situ (trial) efficacy tests

Note: Persons seeking to conduct experimentation involving an unregistered product may need to seek a Research Permit from the APVMA. The trial should comply with all requirements stated in the APVMA research permit as relevant. Further information on permits is available from the APVMA website

Where in situ tested are expected, following the method described below is recommended. The APVMA will consider data generated using alternate methods as long as the data generated support the proposed claims.  Data generated overseas will also be considered.  Justification should be provided as to why the methods described below were not used or how the data generated overseas is relevant to the Australian situation. Such trials should demonstrate that over a four week trial period, the milk supplied can satisfy Australian milk factory requirements for ‘premium milk’ (for >95% of milk shipments). The milk quality parameters should include as a minimum the thermoduric counts and Bactoscan/Total Plate Count.

Trial conditions

Most wash routines for cleaning milking machines and milk vats in Australia involve three processes; a pre-wash rinse cycle (pre-rinse cycle), a (detergent) wash cycle, and a combined post-wash rinse and sanitising cycle (sanitising cycle). The wash cycle comprises the alternating use of alkali and acid detergents (cleansers). The sanitising process is undertaken by using either hot water (~85 °C) or a chemical sanitiser.

It is acknowledged that the in situ on-farm evaluation of dairy cleansers and sanitisers poses a number of logistical challenges and that in general the efficacy evaluation of a proposed new product will necessarily be through its substitution for an existing registered product (or products) within a complete wash routine.

Where on-farm in situ evaluation is necessary it is considered acceptable for the trial protocol to include:

  • A pre-trial period where a wash routine using APVMA registered dairy cleansers and sanitisers are used. This will form the baseline for comparison purposes;
  • A trial period where one (or more) of the dairy cleansers and/or sanitisers is substituted by the trial product;
  • A post-trial period where the pre-trial routine is re-instated.

The trial should be conducted under the typical conditions in which the product is intended to be used. The product (and any registered products used in conjunction) should be used in accordance with the proposed product label instructions in all aspects including, but not limited to, dilution rates, usage volumes, usage temperatures, contact times, water quality, and other operational conditions. The wash routine used during the trial should comply with the equipment manufacturer’s recommendations. Where the product label states that the product is suitable for cleaning and/or sanitising the milk vat and the milking machine then the product should be tested in both situations.

Trial farm selection

The farm(s) selected should satisfy the following criteria:

  • Satisfy the relevant experimental permit conditions
  • Be a registered dairy farm (ie possess a current dairy farm licence)
  • Be of commercial size in terms of herd size, milking machine size and milk vat capacity3
  • Have milking, milk storage and cleaning equipment in a condition that complies with the industry and equipment manufacturers’ guidelines4
  • Have a history (at least six months) of consistently supplying 'premium'5 level milk quality to the dairy factory. The six months milk quality data can be used to provide an historical context for the trial
  • Supply a dairy factory that conducts tests for milk quality—in type and frequency—that are appropriate for the trial data requirements (see footnote).

Number of trial farms

Parameter

Premium Grade

Standard Grade

Sub-standard Grade

Total Plate Count (cfu/ml)  or

Bactoscan

Thermodurics (cfu/ml)

Thermophiles (cfu/ml)

<20,000

 

≤80,000

<2,000

<1,000

20,000‑50,000

 

>80,000‑≤200,000

2,000‑5,000

1,000‑5,000

>50,000

 

>200,000

>5,000

>5,000

The number of trial farms will depend on the label claims regarding operational conditions and water quality. The aim will be to select trial conditions that reflect the full extent of the label claims. For example, if the label claims that the cleanser/sanitiser is suitable for all water types (either by a statement on the label, or by omission) then two trial farms should be used—one with 'soft water' (ie <150 ppm Calcium carbonate), and the other with 'hard water A' (ie >500 ppm Calcium carbonate). Similarly, if the label claims that the cleanser/sanitiser is suitable for use at all water temperatures (either by a statement on the label, or by omission) and a range of dose rates can be used (eg 'use 10–40 mL / 10 L') then four separate trials should be undertaken which include the upper and lower limits of each claim (e.g. ambient temperature solution at 10 and 40 mL /10 L and high temperature solution (85 °C) at 10 and 40 mL / 10 L).

Note: Labels with 'broad ranging' claims (for example, 'suitable for all water types' and 'use at dose rates of 10–40mL / 10 L') may require extensive trialling. In situations where label claims are specific (eg dose rates are related to the level of water hardness) fewer trials will be required.

Trial duration

Trials should be conducted over a four week (28 day) period. However, the period of data collection for analyses should encompass the four weeks immediately prior to and after the trial as depicted below. Data collection through the three four week phases allows for suitable comparisons of performance.

Pre-Trial Period

Trial Period

Post-Trial Period

Prevailing wash routine using APVMA registered dairy cleansers

Wash routine using APVMA trial permitted dairy cleanser(s)

Revert to pre-trial wash routine using APVMA registered dairy cleansers

4 weeks

4 weeks

4 weeks

 

Monitoring and assessment

 

Trial Data

Data should be collected for the entire assessment period (ie pre-trial, trial, and post-trial periods). Information and data relating to each trial should include:

  • Farm details (address, farm size, herd size, type and size of dairy, milk pick-up frequency, milking duration, etc)
  • Assessments of milking and cleaning equipment condition and performance (milking machine test performance test, condition of consumable components, cooling performance, etc)
  • Milk quality parameters (at least Total Plate Count/Bactoscan, Thermodurics) for each pick up,
  • Milk volumes (pick-up volumes)
  • Water quality parameters (source(s), hardness (Calcium carbonate), pH, iron content) taken from the source water and the water from the hot water service(s)
  • Description of prevailing wash routine (must be validated/verified); including volumes, chemicals, dose rates, use temperatures and (re)circulation times
  • A record of any changes, corrective actions, failures etc during the four week trial period
  • Visual inspections of the milking machines (and their componentry) and milk vats for cleanliness. Photographic evidence should be used to support a written record of visual assessments and to facilitate valid comparisons over time.

Visual inspections should include the following:

Milking machine components

  • Dismantling at least 20% of the clusters. Inspection of the milk contact surface of the claw, claw bowl and the liners
  • Inspection of the milk contact surfaces of the milk receiver
  • Inspection of the milk contact surface of the furthest end of the milk line (from the milk receiver). In looped milk lines; inspection of the milk contact surfaces where the milk line connects with the milk receiver.
  • Dismantling the milk filter(s) and inspecting the milk contact surfaces of the filter body.

Milk Vat

  • Inspection of the (internal) milk contact surfaces
  • Inspection of the internal surface of the vat outlet
  • Inspection of the surface of the vat agitator(s).

Trial Methodology

Prior to pre-trial period commencement
  • Assess water quality
  • Complete visual inspection of milking machine components to assess cleanliness (presence or absence of deposits)
  • Complete visual inspection of the milk vat to assess cleanliness (presence or absence of deposits)
  • Confirm that the milking machine cleaning system is operating in accordance to equipment manufacturer’s recommendations (flow rates, effective reserve, slug characteristics, plant drainage, etc). Any changes, corrections, modifications, servicing should be completed prior to commencement of the pre-trial period
  • Document and verify the prevailing wash routine (volumes, chemicals, dose rates, use temperatures and (re)circulation times).
During the pre-trial period
  • Monitor dairy factory milk quality results (test frequency of a minimum of every three pick-ups)
  • Verify the prevailing wash routine (volumes, chemicals, dose rates, use temperatures and (re)circulation times) within four to seven days after commencement of the pre-trial period.
At the end of pre-trial period / start of the trial period
  • Re-assess water quality
  • Complete visual inspection of milking machine components to assess cleanliness (presence or absence of deposits)
  • Complete visual inspection of the milk vat to assess cleanliness (presence or absence of deposits)
  • Implementation of the new wash routine (volumes, chemicals, dose rates, use temperatures and (re)circulation times, slug flow characteristics etc).
Within four to seven days after trial period commencement
  • Verify that the new wash routine parameters comply with the product manufacturer’s recommendation and the wash procedure outlined on the label (concentrations, contact times, temperatures, volumes, etc)
  • For products being tested in the milking machine: complete visual inspection of milking machine components to assess cleanliness (presence or absence of deposits)
  • For products being tested in the milk vat: complete visual inspection of the milk vat to assess cleanliness (presence or absence of deposits).
During the trial period
  • Monitor dairy factory milk quality results (test frequency of a minimum of every three pick-ups).
  • Two weeks after trial commencement:
  • For products being tested in the milking machine: complete visual inspection of milking machine components to assess cleanliness (presence or absence of deposits);
  • For products being tested in the milk vat: complete visual inspection of the milk vat to assess cleanliness (presence or absence of deposits).
At the end of the trial period / start of the post-trial period
  • Verify that the new wash routine parameters still comply with the manufacturer’s recommendation and the wash procedure outlined on the label (concentrations, contact times, temperatures, volumes, etc)
  • For products being tested in the milking machine: visual inspection of milking machine components to assess cleanliness (presence or absence of deposits)
  • For products being tested in the milk vat: visual inspection of the milk vat to assess cleanliness (presence or absence of deposits)
  • Re-instate the pre-trial wash routine (cleansers, concentrations, contact times, temperatures, volumes, slug flows, etc).
Within four to seven days after post-trial period commencement
  • Verify that pre-trial wash routine has been correctly re-instated (concentrations, contact times, temperatures, volumes, etc)
  • For products being tested in the milking machine: visual inspection of defined milking machine components to assess cleanliness (presence or absence of deposits)
  • For products being tested in the milk vat: visual inspection of the milk vat to assess cleanliness (presence or absence of deposits).
During the post-trial period
  • Monitor dairy factory milk quality results (test frequency of a minimum of every three pick-ups).
At the end of the post-trial period
  • For products being tested in the milking machine: Complete visual inspection of milking machine components to assess cleanliness (presence or absence of deposits)
  • For products being tested in the milk vat: Complete visual inspection of the milk vat to assess cleanliness (presence or absence of deposits).

International Data and Assessments

International data can be considered for all application types where the data is relevant to the use proposed in Australia. The APVMA has developed criteria to clearly indicate how international data, standards and assessments can be used as part of the risk assessment process for the approval of an active constituent, registration of a product or approval of a label.

Other considerations

In addition to product efficacy, applicants should ensure that effects on taste of produce and potential residues are considered.

Effects on taste of produce (organoleptic effects)

Where effects on taste or odour cannot be discounted adequate investigation of potential organoleptic effects should be conducted. Taste-panel tests or other organoleptic tests (refer to Australian Standard AS 2542.2.2 – 2014 Sensory analysis - Methodology - Triangle test for test methodology), are recommended to verify that no unacceptable tainting occurs.

Residues

Where residues of the proposed product are likely to remain in the milking machine, lines or vat, after use in accordance with the proposed label instructions (eg after rinsing), residues in milk from subsequent milking should be considered . Further information regarding residues assessments can be found here

References

Australian standards referred to in this document:

1Australian Standards can be accessed through Standards Australia

2AOAC Official Methods of Analysis can be accessed here.

3For example herd size >150 milking cows.

4The milking machines should meet ALL the minimum requirements for milking machine performance as determined by the Australian Milking Machine Trade Association (AMMTA) milking machine test procedure. This should also include a correctly functioning cluster cleaners and air injection system for cleaning purposes. A maintenance program should be in-place with scheduled replacement—as recommended by the manufacturer—of milk contact rubberware, including teat cup liners. The milking machines should be able to drain completely. Cooling performance of the milk vat should comply with Australian Standard AS1187–1996 Farm Milk, cooling and storage systems. In situations where automated cleaning units are used (either for cleaning the vat, the milking machine or both), the cleaning unit(s) should be capable of executing a cleaning program(s) that meets the requirements of the cleanser and/or sanitiser being trialled.

5Example of milk quality criteria thresholds used by one Victorian dairy factory.  Each milk factory will have its own specific milk quality criteria thresholds.

 

To protect your privacy, please do not include contact information in your feedback. If you would like a response, please contact us.