Advice from BuRO on coumatetralyl on products of animal origin

Other advices

BuRO also advises the Ministry of Agriculture, Fisheries, Food Security and Nature to request the Board for the Authorisation of Plant Protection Products and Biocides (Ctgb) to assess the risks to the environment as a result of spreading manure with residues of rodenticides such as coumatetralyl. If necessary, this question should also be put to the European Chemicals Agency (ECHA).

Reason for investigation

Coumatetralyl is the active substance in the biocidal product Racumin Foam, which has been authorised in the Netherlands for the control of house mice. It is a rodenticide that acts as an anticoagulant, which leads to prolongation of blood clotting time and bleeding. When used correctly, the active substance does not enter the food chain.

In 2023, coumatetralyl was found in calf's liver twice as part of the National Residues Plan (NPR). In both cases, the concentration was above the legal standard of 0.01 mg/kg for this substance in liver. This standard is also called the Maximum Residue Limit (MRL).

The Netherlands Food and Consumer Product Safety Authority (NVWA) then inspected the livestock farms from which the calves in question originated. This showed that the product Racumin Foam had been applied incorrectly. Two different livestock farms and two different pest control companies were involved.

Due to these findings, the directorate Enforcement of the NVWA asked BuRO for a risk assessment.

Questions and answered

Based on the risk assessment, the questions posed can be answered.

Based on the findings from the NPR, is it possible to say anything about the extent of the problem (that animals may be contaminated with coumatetralyl)?

With the help of statistics, BuRO estimates that the legal standard (MRL) is exceeded in 2% of the calves. We make this estimate based on findings in the random liver samples that were taken within the 2023 NPR, and it varies between 0.1 and 6.6%.

What is the size of the sample per flock of animals in order to be able to conclude about the presence of coumatetralyl in animals when samples are taken from high-risk farms, based on analytical results?

In order to determine with a certain degree of certainty if coumatetralyl is present in animals, samples must be taken according to the 'Freedom from disease model'.

The commonly used rule of thumb to sample animals (n+1), where n is the number of animals in the flock, is not a statistically based method. This rule of thumb does not provide certainty about the proportion of animals that are or are not contaminated.

Should pork skin be sampled?

BuRO concludes that sampling pork skin is not necessary, as coumatetralyl accumulates in liver and not in skin.

Does the consumption of calf's liver or veal contaminated with coumatetralyl pose a risk to consumer health?

The consumption of veal or calf's liver with coumatetralyl does not pose a risk to adult health. This can be concluded based on results of chemical analysis of livers from 55 calves and 36 pigs.

A single consumption of calf's or pork liver with a high concentration may pose a risk to children's health. Possible effects include the disruption of blood clotting, such as a nosebleed, bleeding gums, bruising, or blood in urine and faeces.

Consumption of veal and pork is safe because coumatetralyl has not been found above the quantification limit in any sample of veal and pork.

Does consumption of calf's liver contaminated with coumatetralyl pose a risk to cats and dogs?

BuRO concludes that a risk to the health of dogs weighing 25 kg and cats weighing 4 kg cannot be excluded. This is because the portions of liver that can be eaten before the health-based limit value is exceeded are no greater than the amounts that dogs and cats of this weight normally eat.

Is it possible, by calculation, to indicate how long after exposure the concentrations of coumatetralyl in the liver or meat of exposed (live) farm animals are below the maximum residue limit (MRL)?

Based on half-lives in rat and mouse livers, it can be calculated that the highest measured concentration in live animals will have decreased to the level of the MRL after 45 to almost 1000 days. However, the calculations are uncertain, as half-lives for farm animals are not available.

Does the spreading of manure contaminated with coumatetralyl on grassland pose a risk to the health of livestock or the consumer, as a consequence of the livestock consuming the resulting grass/hay?

This question cannot be answered. This type of exposure is not included in the risk assessment for product authorisation. It is therefore not possible to compare the current situation with the expected, normal situation.

Does the spreading of manure contaminated with coumatetralyl on grassland pose a risk to the environment (e.g. leaching into ditches)?

Due to the lack of information on the concentration in surface water around the farms in question, no statement can be made about the risk to the environment.