Research and analysis

Quarter 4 2023 report on the pesticide residues monitoring programme: issues arising in this report, follow-up from previous reports and plans for the quarter 1 2024 report

Updated 25 September 2024

Issues arising in this report

Chlorate

We have been testing a limited number of foods for chlorate since 2016. The pesticide sodium chlorate is a residual broad action weed killer that is not authorised for use in the EU or UK. However, we are confident that the residues we are detecting come from use of chlorine-based disinfectants used to maintain microbiological safety (control microorganisms that cause food poisoning). Because these residues are unavoidable, and important for the maintaining of microbiological control vital for food safety, we are not treating these results as breaches of the MRL. We are not advising that food companies change their existing practices as a result of our findings, but they should be aware about the ongoing discussion in this area.

We are only part of the work going on across government and beyond to consider what to do about chlorate residues in food and water.

How chlorate MRLs take account of use of biocides

The footnote included in the chlorate MRLs takes into account chlorate residues incurred during the processing of food (from treated water or processing aids, such as biocides). The footnote exceptionally specifies that for considering compliance with chlorate MRLs, simple types of processing, such as packing, washing, chopping and freezing can be taken into account. Chlorate in irrigation water is taken into account in the MRLs as set and no further adjustment can be considered.

The responsibility for providing evidence showing that residues from processing can be taken into account, lies with the food business operator, and so we will be interested to see such evidence where appropriate. HSE will decide whether the footnote can be applied and if so this will be reflected in our reports.

Read more information on the Chilled Food Association’s website, produced by the Food and Biocides Industry Group.

Infant food

Infant food MRLs are set under separate legislation managed by UK health departments. The footnote that applies to other foods cannot be used for infant foods, although residues occur for the same reasons. UK health departments are working with HSE and FSA to resolve this.

Sanitisers

The presence of low-level residues of chlorate in food results from measures taken by the food and water industries to protect food safety by reducing microbiological contamination of food and drink (including drinking water, which is a significant source of chlorate in food). Chlorate itself is not used as a disinfectant, but chlorine-based sanitisers contain small amounts of chlorate. The Food Standards Agency has worked with industry who promote best practice and guidance for use of sanitisers.

Drinking water

In national legislation throughout the UK, it is already a requirement to keep disinfection by-products as low as possible. This is usually achieved through management of disinfectant dosing and storage.

Microbiological safety of food

The HSE is working with the Advisory Committee on the Microbiological Safety of Food to understand how changes to pesticide MRLs affect biocide use, microbiological food safety, and any change to the overall risk to consumers taking into account both chemical and microbiological safety.

Dietary intakes

Since 2018 the Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment (COT) has been considering chlorate as part of its on-going work looking at the chemicals in the diet of infants and young children (up to 5 years). The European Food Safety Authority’s 2015 opinion on chlorate establishes appropriate health-based guidance values for chlorate exposure to protect against acute and chronic risks to health.

Fosetyl-Al (sum)

The full residue definition is ‘fosetyl-Al (sum of fosetyl, phosphonic acid and their salts, expressed as fosetyl)’. Throughout this report that definition is reflected as fosetyl (sum) All the residues reported as fosetyl (sum) in this report were detected as phosphonic acid.

Fosetyl-Al breaks down to phosphonic acid, but phosphoric acid can also be a residue left by use of pesticides containing disodium phosphonate or potassium phosphonates. Additionally, products sold as fertilizers also can contain or break down to phosphonic acid. And finally, phosphonic acid also occurs naturally in the environment. The presence of phosphonic acid does not necessarily mean that a pesticide was used. Those producing food need to be aware that the use of products that contain phosphonic acid or break down to phosphonic acid may lead to produce which breaches the MRL.

DDT

The use of DDT is banned or heavily restricted in many countries. It is not allowed for use on food crops anymore, but it is still used in some countries outside the EU as a public health insecticide. Residues of DDT take a long time to break down in the environment and can accumulate in fatty tissue which is a major reason that it has been banned in the EU and many other countries.

Due to the bans and restrictions on use the levels in food have decreased substantially since the 1960s and 1970s. Even so, because it takes a long time to break down we do expect, and do see, occasional DDT residues in our monitoring results. Overall, the incidence and the size of residues have fallen steadily over time, which is what we would expect. In recent years none of our findings were unusual, unexpected or of concern. We can tell from the chemical form that we detect whether the residues we have found are from historic use (which is what we usually find). Historic use is indicated by the detection of DDE which is a break down product of DDT. We explain this every time we publish DDT results to try to make it as clear as we can that the results show food producers are not using DDT today. However, there are occasional media stories about DDT and various links and associations, which do not make this distinction.

The residues we find nowadays are at levels that would not be expected to have any effect on health, either in the short term or in the long term, when checked against today’s understanding of the effect of DDT on health. As a committee, we take care to ensure we look thoroughly at this, and the Food Standards Agency is also actively involved in our considerations.

Processing factors

As the surveillance programme monitors residues in all types of food, from raw commodities (for example, potatoes) to processed (for example, wine), dried (for example, dried fruit) and composite foods (for example, fruit bread), consumer risk assessments are specifically tailored to address processed and mixed food products. MRLs are generally set for raw commodities, although when MRLs are established the assessment of dietary intakes takes into account the potential for residues to remain in processed foods produced from the raw agricultural commodities. MRLs have been set for processed infant foods, and in future may be extended to other processed food products.

MRLs apply to all traded foods, including foods used as ingredients. The law specifies the level to apply to foods as they are traded. For almost all foods that means their raw, unprocessed form. But MRLs also apply to prepared and processed foods in which case the effect of processing needs to be taken into account.

In nearly all cases the MRL is set for the food in its raw, unprocessed form (the form of each food to which MRLs apply is listed in Annex I of Regulation 396/2005). These MRLs can be applied to processed foods using appropriate processing factors. Processing factors take account of the effect of processing on the food as traded. Different forms of processing may remove, concentrate, or dilute residues, and the effect may vary depending on the food and the pesticide concerned. Multiplying the processing factor by the original MRL gives a calculated MRL that can indicate the food was made with an ingredient or ingredients which had residues over the original MRL.

Calculating the MRLs for processed goods is dependent on the information available. HSE will contact the supplier if residues exceed the calculated MRL to give them an opportunity to provide relevant information to support the calculation.

HSE use the general principle that if no specific processing factor is available, a default factor of 1 may be applied. In this report, we have mostly applied processing factors from the European database of processing factors for pesticide residues in food version 2.

For maleic hydrazide in potato crisps, we have applied a processing factor taken from the Peer review of the pesticide risk assessment of the active substance maleic hydrazide.

Processing factors and MRLs used for bread

Food type	Pesticide	Processing factor	MRL for unprocessed grain (mg per kg)	Bread MRL (mg per kg)
Bread (speciality bread: bagels)	cypermethrin (sum)	0.48	2	0.96
Bread (speciality bread: croissants)	cypermethrin (sum)	0.48	2	0.96
Bread (speciality bread: waffles)	cypermethrin (sum)	0.48	2	0.96
Bread (ordinary bread: other)	glyphosate	0.12	10	1.2
Bread (ordinary bread: white)	glyphosate	0.12	10	1.2
Bread (ordinary bread: wholemeal)	glyphosate	1.2	10	12.00
Bread (ordinary bread: bagels)	glyphosate	0.12	10	1.2
Bread (speciality bread: croissants)	glyphosate	0.12	10	1.2
Bread (speciality bread: muffins)	glyphosate	0.12	10	1.2
Bread (ordinary bread: other)	chlormequat	0.71	7	4.97
Bread (ordinary bread: white)	chlormequat	0.71	7	4.97
Bread (ordinary bread: wholemeal)	chlormequat	1.3	7	9.10
Bread (ordinary bread: bagels)	chlormequat	0.71	7	4.97
Bread (speciality bread: brioche)	chlormequat	0.71	7	4.97
Bread (speciality bread: croissants)	chlormequat	0.71	7	4.97
Bread (speciality bread: crumpets)	chlormequat	0.71	7	4.97
Bread (speciality bread: muffins)	chlormequat	0.71	7	4.97
Bread (speciality bread: pancakes)	chlormequat	0.71	7	4.97
Bread (speciality bread: pikelets)	chlormequat	0.71	7	4.97
Bread (speciality bread: scones)	chlormequat	0.71	7	4.97
Bread (speciality bread: waffles)	chlormequat	0.71	7	4.97

Processing factors and MRLs used for crisps (potato based)

Food type	Pesticide	Processing factor	MRL for potatoes (mg per kg)	Crisps MRL (mg per kg)
Crisps (potato based)	1,4-dimethylnapthalene	0.2	15	3
Crisps (potato based)	maleic hydrazide	3.81	60	229
Crisps (potato based)	fluopyram	<0.63	0.15	0.09

Processing factors and MRLs used for orange juice

Food type	Pesticide	Processing factor	MRL for oranges (mg per kg)	Orange juice MRL (mg per kg)
Orange juice	imazalil	0.06	4	0.24

Processing factors and MRLs used for pineapple

Food type	Pesticide	Processing factor	MRL for pineapple (mg per kg)	Tinned pineapple MRL (mg per kg)
Tinned pineapple	ethephon	0.25	2	0.5

Processing factors and MRLs used for rye flour

Food type	Pesticide	Processing factor	MRL for unprocessed grain (mg per kg)	Flour MRL (mg per kg)
Rye flour (other)	glyphosate	0.45	10	4.50

Follow-up from previous reports

Quarter 3 2023 - Pears with pods (UK) - Spinosad

Sample: 3040/2023

The Chemicals Regulation Division (CRD) investigation determined that the most likely explanation for the residue found in sample 3040/2023 was spray drift from the authorised application of Tracer (M12438) to sprouts in the field adjacent to the peas, in close proximity to the harvest dates. HSE has given advice to the grower as a reminder of their duties under the PPP legislation and the case is now closed.

In our quarter 1 2024 report

Samples collected in Great Britain

In quarter 1 of 2024 we will look at results from samples collected in Great Britain for:

• Aubergine
• Banana
• Beans with pods (green)
• Beans with pods (speciality)
• Beef
• Beetroot
• Broccoli
• Chilli peppers
• Eggs
• Garlic
• Grapefruit
• Grapes
• Limes
• Melon
• Milk
• Mushrooms
• Peppers (sweet)
• Potatoes
• Speciality vegetables (root)
• Tomatoes (processed)
• Wheat flour

Samples collected in Northern Ireland – provisional

In quarter 1 of 2024 we will look at results from samples collected in Northern Ireland for:

• Aubergine
• Banana
• Beans with pods
• Beef
• Beetroot
• Broccoli
• Chilli Peppers
• Eggs
• Fish (white)
• Grapefruit
• Grapes
• Limes
• Melon
• Milk
• Mushrooms
• Peppers (sweet)
• Potatoes
• Sweet potatoes

This document is part 4 of 4 of the Quarter 4 2023 report.

Previous: Quarter 4 2023 report on the pesticide residues monitoring programme: findings by food in Northern Ireland and risk assessments.

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