Food Safety Aspects of the Natural Contaminants - Mycotoxins and Nitrates

Many mycotoxins are known genotoxic carcinogens. The incidence of mycotoxins in a wide range of foods requires further investigation to establish whether levels observed are a potential risk to human health.

These types of chemical contamination arise as a result of natural processes. The aim of the research programme is to understand the way in which these contaminants are produced in food and to what extent, and to identify ways in which the risk to consumers can be reduced, for example through codes of good practice.

The programme is in support of the Agency's strategy on chemical safety of food and seeks to assist in achieving the Agency's goal 'to ensure that chemicals present in food do not compromise food safety'.

Many mycotoxins are known genotoxic carcinogens. The incidence of mycotoxins in a wide range of foods requires further investigation to establish whether levels observed are a potential risk to human health. Recent information has highlighted new potential food safety concerns and these will be investigated. This work will use and build on the current body of knowledge to identify the critical factors that contribute to contaminant formation and investigate ways to modulate their effect.

Research will focus on the nitrate formed in vegetables during growth. The work will extend the investigation of the fate of dietary nitrate in the stomach and clarify health issues. It will also fulfil our statutory obligation to monitor levels of nitrate in UK-grown lettuce and spinach and monitor levels in other salad vegetables. In an extension to this approach, the research will also investigate nitrate exposure levels for certain vulnerable sub-groups of the population, for example babies and toddlers.

The work should enable the Food Standards Agency to assess and reduce the risk to consumers from chemicals present in food due to natural processes. The whole programme of research on mycotoxins and nitrate supports our negotiating position at both European and international fora, which in turn will facilitate the setting of appropriate limits for food contaminants, thereby protecting the UK consumer.

The Division's programme of research and surveillance supports the Agency's strategic objectives of:

• Ensuring that chemicals present in food do not compromise food safety and developing policies to further reduce exposure to consumers.
• Ensuring controls are in place and properly enforced.
• Encouraging open debate of the issues amongst stakeholders.

Chemical contaminants that are present in food may present a risk to human health. Mycotoxins are produced by fungal contaminants, for example aflatoxin, whereas in the case of nitrate in leafy vegetables contamination is a combination of environmental and natural effects. By their very nature the control of the levels of these contaminants involves the co-operation of the whole production chain, ie from farm to fork. The Agency aims to ensure that these contaminants do not compromise food safety through negotiation of appropriate legislation in Europe and at other international fora. To support this policy the Agency carries out an extensive programme of research and surveillance work on mycotoxins and nitrate in foods which is well established and due for review in 2003. The Agency has established good collaborative working patterns with other government departments and a wide range of stakeholders from industry, retail and consumer based organisations both in the UK and internationally.

The food safety concerns connected to mycotoxin contaminants are well documented. Mycotoxin contamination is inherently heterogeneous and studies have also demonstrated that their occurrence is spasmodic, so sampling procedures are of paramount importance. Procedures appropriate for sampling products on sale in the shops will be different from those appropriate for bulk consignments at the point of import. Furthermore, each food is likely to have a different mycotoxin occurrence pattern dependant on the nature of processing that it undergoes. So for those foods susceptible to mycotoxin contamination which are finely ground, the final distribution may be more even than those products where individual kernels remain intact.

This programme covers mycotoxins that have long posed a threat to consumer safety, such as aflatoxins, as well as those which have only recently been identified as being of concern, such as tricothecenes. In particular, recent studies have highlighted the issues surrounding field moulds/fungi that occur in temperate climates such as those found in Europe. The Agency will ensure that it is up to date with developments in R&D in this area in Europe and internationally through participation and attendance at meetings and symposia. Where new information indicates that there may be possible health concerns for the UK consumer the Agency will act rapidly, through targeted food surveys, to gather relevant data and advise consumers of the dietary implications.

The Agency will continue to pursue the comprehensive programme of surveillance for mycotoxin contamination; this enables informed negotiating in Brussels and other international fora, checks for compliance with UK limits and ensures the continued protection of consumer safety in the UK through up-to-date dietary exposure calculations. An agreed sampling pattern has been set for bulk commodities at point of import, and now a similarly robust method needs to be defined and agreed for retail sampling. The Agency will work in conjunction with industry to study distribution patterns through a production run, or batch, to identify a defensible retail sampling plan. This information will be referred to UK enforcement agencies and the European Commission.

The Agency is currently investigating the possibility of using biomarkers to estimate consumer exposure to mycotoxins. It is using ochratoxin A as an example and tracking its excretion through urine samples supported by in-depth consumption data. The extension of this approach will be further investigated for other mycotoxins.

The Agency has a programme of co-ordinated research and surveillance on nitrate, ranging from the statutory monitoring of lettuce and spinach in support of the UK's derogation to a major research dietary study. The Agency has worked in the recent past to establish good links with other government departments, including DEFRA, and stakeholders, such as growers and trade federations.

The European Commission has set maximum levels for nitrate in lettuce and spinach and as part of these provisions the Agency is required to supply monitoring data on an annual basis. In addition, the EC has announced its intention to extend the maximum limits to cover other salad vegetables and foods intended for infants. The Agency will gather pertinent data through targeted research and surveillance projects to inform these negotiations from a UK perspective and a position of knowledge. This work will benefit the consumer by ensuring that particularly vulnerable sub-groups of the population are protected by the setting of informed regulation and support the Agency’s core aim to ‘protect public health from risks that may arise in connection with the consumption of food’.

The present toxicological opinion on the health effects of dietary nitrate consumption is frequently challenged. The Agency is investigating the health effects of nitrate consumption on human health, through correlation of dietary intake and the incidence of related biomarkers. The Agency is also reviewing new toxicological data published since the expert committee last considered this issue. These will enable an up-to-date assessment of the health effects to be made, thereby ensuring best advice to the UK consumer.

The Agency has instigated and will continue to commission work that investigates the observed analytical discrepancies in nitrate analysis. The Agency will encourage the outcome of this research to become part of the Code of Practice thus allowing compliance to be monitored with confidence by both producer and enforcer, to the benefit of the UK consumer.

Name: Dr Wendy Matthews
Tel: 020 7276 8708
Email: wendy.matthews@foodstandards.gsi.gov.uk