Understanding Chlorate Downgrades

Summary:

Here you’ll find common milk smell and flavour issues, what causes them, and simple ways to identify and prevent them on farm.

Chlorate is a residue found in milk formed when chlorine-based products, especially hypochlorite used for sanitising, break down through oxidation.

Downgrade support

The Minor downgrade trigger level is ≥ 0.02 mg/kg. The Major downgrade has a trigger of ≥ 0.1 mg/kg.

Organise a traceback

If you cannot determine the cause of the test result or you receive downgrades, call the Farm Source Service Centre.

Depending on the duration and severity of the issue, they will organise an on-farm trace back and take you through the Milk Quality Support Programme.

Refund support

Fonterra will refund up to the total amount of the deductions made under Clause 9.5 of the Fonterra Farmers’ Terms of Supply (“Terms of Supply”), in the current season, to cover the cost of help from a Fonterra approved service provider to solve milk quality problem.

Please refer the Terms of Supply Clause 9.7 for more information.

What are some key causes of chlorates on farm:

Based on farmer traceback the following are key trends occurring at a farm level:

Most farmers spoken to added hypochlorite to their final wash
Several farmers did not complete a final rinse after their acid wash
Many farmers increased hypochlorite dosages in poor weather, both in the water supply and wash cycle
Chlorine dosage rates were not typically measured well for both water and cleaning purposes
Chlorine products were typically stored in 100/200L drums and expiry dates were not monitored, so some Chlorine stock had well passed the expiry date.

What is the toxicity, exposure and health risks associated with chlorates?

Due to regulatory changes within the European Union, chlorate (ClO3-) has come into focus as a residue of interest in a growing number of NZ’s dairy markets.

Acute Human Health Effects:

Acute chlorate poisoning is very rare and requires ingesting large amounts
It is not relevant to dairy exposure.

Chronic human health effects:

Chlorate can affect thyroid function by interfering with iodide uptake.
Safe daily intake limits are set at low levels for long-term exposure.

Limits in drinking water:

Drinking water guidelines set low allowable chlorate levels.
Limits apply but must not compromise water disinfection.

Customer specifications:

Chlorate can come from multiple sources, including water and food processing.
Customer limits are often stricter than regulations, especially for products like infant formula.