Co-ops cracking down on chlorine

Aurivo, Lakeland Dairies and Tipperary Co-op have implemented new control programmes to eliminate the use of chlorine-based detergent sterilisers from their suppliers’ farms. Dairygold and Glanbia have not banned the use of chlorine, but they are meeting their suppliers on a one-to-one basis to review their washing protocol.

The issue with chlorine-based cleaning products is that it can cause chlorate residues to show up in dairy products if not washed out properly. Of particular concern to milk processors is chlorate residues in infant powder. High chlorate levels can inhibit the uptake of iodine in the infant’s thyroid so there are strict limits on chlorate levels. Not surprisingly, milk processors want to keep on the right side of acceptable levels and this is only right.

However, according to Teagasc researcher David Gleeson, chlorine-based sterilisers are not the problem; rather, it is the incorrect use of them that is leaving chlorate residues in milk. He says that when milking machines are washed with chlorine using the correct procedure, there should be no issues with chlorate residues in milk.

So it appears that some milk processors have taken a strategic decision that it is better not to use chlorine-based sterilisers at all, rather than risk having residues. While this might well be in the best interests of securing a market for product, it will affect their farmer suppliers. Chlorine is no longer used in cleaning milk processing plants so chlorate in milk can only come from farms.

Removing chlorine-based detergent sterilisers from farms is going to have consequences. Firstly, chlorine is very good at cleaning milking plants, particularly at removing protein deposits.

Using chlorine-free cleaning agents will require more hot washes, higher product usage rates, longer wash routines, more acid washes and the use of different products for washing. The net result will be more complicated wash routines and extra costs.

There are three main areas where farmers incorrectly use chlorine-based detergent sterilisers which can cause chlorate residues in milk. The first is in the quantities used – ie using too much detergent steriliser and not using enough post-rinse water to rinse the plant before the next milking.

Detergent sterilisers with chlorine should never be left in the plant until the next milking; they should always be rinsed immediately after the wash circulation with 14l of water per milking unit. Chloris should never be added to the wash or to the final rinse.

The second issue is when it comes to washing bulk tanks. There can be issues with the calibration of automatic wash units which are on most modern bulk tanks. Not using the right amount of product and water is the main issue. Many modern bulk tanks have economical wash modes, which effectively means that less water is being used. This mode is not recommended when chlorine-based detergent sterilisers are used.

The next issue is the shelf life of chlorine-based products. Chlorine is converted to chlorate over time. So the longer from manufacture that a product is used, the more chlorate it will contain. Exposure to sunlight will speed up the conversion of chlorine to chlorate. Therefore, chlorine-based detergent sterilisers should only be purchased close to when they are going to be used. Do not buy it in bulk and do not expose containers of detergent sterilisers to direct sunlight.

The alternatives

So what can you do if you can’t use chlorine? To begin with, not all farmers use chlorine-based detergent sterilisers as it is. Many farmers just use caustic powders and when combined with regular hot washes and an acid descaler once a week, they have no problems with plant cleanliness or chlorate residues, as chlorine is not being used.

However, powder detergents have higher caustic contents compared with caustic liquid detergents. The problem with powder-based detergents is that they are not compatible with automatic washing systems, either on milking machines or on bulk tanks, so only liquid detergents can be used with these.

Therefore, extra hot washes will be required when using liquid detergents. Tipperary Co-op recommends three hot washes a week with chlorine-free liquid detergent on top of the once-weekly hot acid descaler wash. It does not recommend re-using the wash solution after a hot wash, but the solution can be re-used after a cold wash.

It also recommends using a hydrogen peroxide sanitiser once a week with one of the hot detergent washes and using peracetic acid in every final rinse. However, most automatic wash units are not designed to use more than one product at any one time. While most have two intakes (usually detergent/acid), the programs are not designed to use both at the one time, so if extra products need to be used to keep the plant clean, then these will have to be added manually.

New products

Faced with the limitations on the future use of chlorine in detergents, manufacturers are coming up with new chlorine-free liquid detergents. Teagasc Moorepark is involved in trialling some of these.

David Gleeson says that it is not until two or three months after using a new product that you will know if it is working well or not. Removing protein deposits seems to be the biggest issue and when these build up on the internal surfaces of pipes, they will lead to a dirty plant and high TBC.

Teagasc published a list of registered detergent sterilisers and a list of caustic detergents on the Irish market. The list is not a recommended list, it is just a list of products that have been registered with the Department of Agriculture and can be legally sold on the Irish market with a PCS number. In the event of a cross-compliance inspection, you will be required to furnish a PCS number for each chemical on the farm.

The best policy, regardless of whether or not your milk processor is accepting the use of chlorine-based detergent sterilisers or not, is to re-evaluate your current system. Measure the contents of wash troughs and size accordingly. You need a minimum of 14l per milking unit. Use a measuring jug to add the right amount of product to the wash cycle. Put a clock in the dairy to time the wash cycle. Write up a timetable of what wash to use each day, morning and evening, and leave it in the dairy so everybody can see.

Common problems