How to manage without chlorine

From January 2021, chlorine is not permitted for use in products for cleaning milking parlours and bulk milk tanks, as it leaves a residue in both butter and infant dairy formula.

While steps were being taken to reduce the residues through using correct wash procedures, Ornua announced last January that it was banning the use of chlorine across its supply chain.

Removing chlorine from wash products raises the question about what is going to replace it. According to David Gleeson from Teagasc, there are a number of ways to compensate for the loss of chlorine.

Caustic content

The first is to increase the caustic content in the wash solution. Most of the existing liquid detergent sterilisers on the market have caustic and chlorine in varying quantities.

When chlorine is removed, the percentage of caustic in the product needs to increase to compensate.

The percentage of caustic in chlorine-free detergents ranges from 10% to almost 40%

David recommends that the caustic content of the wash solution should be 0.7% and 1% for hot and cold washes respectively.

The percentage of caustic in chlorine-free detergents ranges from 10% to almost 40% and based on recommended usage rates, the caustic content in the wash will range from 0.5% to 3%.

The next step to compensate for the loss of chlorine is to use extra hot washes. David suggests seven hot washes per week when using liquid detergents. Fewer hot washes are needed when using powder based products as the percentage of caustic in powder products is very high anyway, typically 76% caustic compared to 10% to 39% caustic in liquid detergents. The temperature of the hot water is critical. It needs to be between 75°C to 80°C at the start of the wash cycle and 50°C at the end of the wash cycle.

David says one of the issues he finds on farms is that circulation times are too long. Ten minutes is the optimum time for the wash to circulate.

The combination of very hot water and detergent removes milk residues from the inside of pipes and clusters, etc.

When the water cools down some of these milk residues and fat deposits will re-attach to the surfaces of equipment, undoing the good of the wash. Therefore, discard the first five litres of the wash and don’t circulate the wash for too long and allow it to get cold.

Acid descale washes

The third step recommended by David is to increase the use of existing acid descale washes.

Most farmers would have completed an acid descale wash once per week while on a chlorine-based wash routine. However, David says that extra acid washes are required when on a chlorine-free wash routine. He recommends three descale washes per week.

There are currently two products registered for use in Ireland

Another option is to use an acid-based ‘one for all’ product. There are currently two products registered for use in Ireland.

Peracetic acid

The fourth step to compensate for the loss of chlorine is the introduction of an additional product – usually peracetic acid in an additional final rinse.

Peracetic acid is usually included at a rate of 60ml per 45l of wash. No extra rinses are required after the peracetic acid rinse but the machine should be rinsed after the main wash cycle and before the peracetic acid cycle.

Remember, when using chlorine-free liquid products, the wash solution should not be recycled.

Choosing the product

The transition to chlorine-free cleaning agents is not without its difficulties. Many farmers who have switched to chlorine-free during 2019 have experienced problems with elevated levels of TBC in their milk.

It usually takes three months of being on chlorine-free products for problems to arise and most issues occur on non-stainless steel surfaces such as claw pieces and milk meters.

A Teagasc study conducted on 36 dairy farms using a range of chlorine and chlorine-free products found that, based on TBC levels, the chlorine-free products significantly out-performed the farms using chlorine-based products. The average TBC on the 25 chlorine-free farms was 5,759 CFU/ml in April, 4,644 CFU/ml in September and 11,637 CFU/ml in November.

David Gleeson says that this shows that when users are focused, when they have received specific guidance and when the protocol is correctly implemented there should not be issues with using chlorine-free products.

Kerry Group did their own mini-trial of seven different chlorine-free products over a a six month trial.

Each of the seven products were assigned to five milk suppliers and TBC and thermoduric levels and thermoduric levels were monitored from the farms.

Some products performed better than others.

The results of the trial are helping Kerry Agribusiness to decide on what products they will stock in their stores.

Going forward, they are likely to stock the following four brands; Hypral One (Grassland Agro), Avalksan LC (Carbon Group), Autosan Blue (Kilco) and Deosan Liquid CIP (Deosan).

Other issues

It’s critical to re-calibrate automatic washer settings for milking machines and bulk tanks.

Chlorine-free products are more viscous than chlorine-based products as they have a higher concentration of product.

Suck up tubes are more likely to get blocked over time

Due to the extra viscosity, the speed at which the product will be sucked up will be slower, so the machine may have to pump for longer.

Similarly, suck up tubes are more likely to get blocked over time.

David Gleeson recommends that these tubes should be cleaned or replaced as part of the annual service.

Another issue is that due to the swing away from chlorine-based products, many existing products have not been registered with the Pesticide Control Service and therefore have no official PCS number.

This could present a problem for farmers that have these products in stock, or buy these products during the year and subsequently get a cross compliance inspection.

A list of approved detergent steriliser products is available on the Teagasc website.

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