Evaluation of how chlorine-free cleaning protocols for milking equipment are applied on farms

A requirement for chlorine-free cleaning of milking equipment on-farm has been adopted by milk processors since January 2021. To address this scenario (and to compensate for the removal of chlorine), five new milking machine cleaning protocols have been developed and evaluated at Moorepark.

The new cleaning protocols (compared to traditional protocols) require more frequent hot washes to be conducted at higher temperatures. In addition, the new chlorine-free (CF) sodium hydroxide based detergents have a higher viscosity than previous products and therefore recalibration of automated cleaning equipment is vital; otherwise, the new CF detergent take-up rate may be less than that of the previous product.

As Irish dairy farmers approach the end of their second season producing milk using these new CF cleaning detergents, some farmers/advisors continue to report issues with milking equipment hygiene and an increase in bacterial counts. To establish potential reasons for this observation, Teagasc undertook a survey focusing on milk quality management on commercial dairy farms.

Farms visited

Some 105 farms were visited in co-operation with 11 milk processors between July and October 2022. The number of farms chosen from each processor was based on the total supplier numbers of each processor; between five and 20 farms were selected per processor; with half of the farmers surveyed having a consistently high (>25k) or low (<15K) total bacteria count (TBC).

Participating farmers did not receive specific advice on TBC management in the two months previous to the Teagasc visit. Each farmer was interviewed using a set number of questions and detergent usage rates, water temperatures and water volumes were measured.

Results

Many deficiencies in the application of the cleaning protocols were highlighted, in particular the frequency of hot washes, detergent circulation time, temperatures and chemical usage rates; particularly where liquid products were used with automatic cleaning.

A summary of the main faults associated with the use of liquid detergents is presented in Table 1. Higher usage rates (1% solution) of CF liquid detergent are required when detergents are used with cold water, to compensate for the lack of heat, whilst a usage rate of 0.5% is sufficient where hot water is employed.

97% of farmers surveyed were not observing this requirement. In addition, 38% of farmers were not using sufficient amounts of detergent when using hot water. Many farmers indicated that they had not recalibrated the auto-washer to facilitate the use of the new CF products. To properly recalibrate an auto-washer, it is necessary to read the recommendations on the drum, for both hot and cold-washing, ascertain the volume of water being used (measure the trough), calculate how much detergent should be used and recalibrate as necessary.

The frequency of hot washing for the milking plant depends on the wash routine employed; a minimum requirement of seven hot washes per week are necessary when liquid detergents are used. A target starting wash temperature of 75-80^oC is necessary for effective hot washing. A minimum of 9L of hot water per unit is required for effective cleaning and this increases to 12L per unit with larger plants that have axillary equipment, e.g. milk meters/dump lines.

14% of farmers used less than 7L per unit. It is recommended to conduct an acid wash on a least two occasions per week and more frequently if the water used is considered ‘hard’ (> 300ppm CaCO₃).

Acid containers are generally identified as being red in colour and should match with the red take-up tubes to avoid incorrect product being used. 8% of farms had these tubes placed incorrectly. 22% of farms had an organic matter residue build-up on the inside of claw-pieces-indicating that a poor milking equipment cleaning protocol is employed on those farms (Figure 1).

Table 1: Summary of main faults associated with the use of liquid detergents

Figure 1: Residue build up on the claw bowl

Conclusions

The results of this survey indicate that there are many faults in the application of cleaning protocols on farms. If these management faults are not addressed, the success of CF cleaning at farm level will be limited and bacterial counts in milk may increase over time.

This article by David Gleeson, Lorna Twomey and Bernadette O’Brien first appeared in the Moorepark 2023 Dairy Open Day Booklet. The authors acknowledged the 11 participating processors and DAFM Dairy Levy Trust for funding this research.

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