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MAFF UK - FLUORESCENT WHITENING AGENTS

Index to MAFF UK Food Surveillance Information Sheets, 1995

Summary

The Food Safety Directorate has completed a survey to measure the extent of use of fluorescent whitening agents (FWAs) in paper and board used for food packaging and other uses where it is likely to come into contact with food. This work is part of its surveillance programme to monitor potential contamination of food by chemicals migrating from food contact materials. The survey covered 117 samples of paper and board including food packaging, tea bags, coffee filters, paper plates, kitchen towels and napkins. The samples were examined under ultraviolet (UV) light and those which showed fluorescence (an indicator of the presence of FWAs) analysed to determine the concentrations of FWAs present. Thirty-seven samples did not show fluorescence. Most of the samples analysed (65 out of 80) contained FWAs at 50 mg/kg or below. The highest concentrations of FWAs were found in some of the packaging used for take-away food - four samples contained FWAs at 430-1160 mg/kg paper.

Background

Paper and board used for packaging and other applications, such as writing paper, is generally bleached to produce the product 'whiteness' required by consumers. With some paper and carton board materials fluorescent whitening agents (FWAs) are also included in, or on, the surface of the paper to achieve a higher standard of whiteness. It had been suggested that some of the substances used as FWAs may cause harmful effects to human health. A survey was carried out to identify the types of substances used as FWAs, and the concentrations at which they are used. The survey covered paper and board products likely to come into contact with food, such as paper and board food packaging, tea bags, coffee filters, paper plates, kitchen towels and napkins.

Method

The samples of paper and board were examined under ultraviolet (UV) light. Those which showed fluorescence were then analysed for FWAs. The sample was extracted using cold water, 50 percent v/v methanol/water or 50 percent v/v ethanol/water, and the type and concentration of FWA present determined by high pressure liquid chromatography (HPLC). The limit of detection varied depending on the type of FWA, but was typically between 0.5 and 1 mg/kg paper.

Results

A summary of the concentrations of the FWAs found by the survey are given in Table 1. Thirty-seven samples did not show fluorescence under UV light. The samples showing fluorescence were analysed and FWAs were not detected in 21 of these samples. The categories of samples found not to contain FWAs, either by fluorescence or analysis, were tea bags and coffee filters, dairy wraps, absorbent pads from e.g. meat trays, lids of containers used for microwave cooking and pre-prepared foods, and wrapping on a meat product. The majority of samples analysed (65 out of 80) contained 50 mg FWA/kg paper or below. The highest concentration of FWAs was found in some of the packaging for take-away food - 4 samples contained FWAs at 430-1160 mg/kg paper. In most of the samples composed of more than one layer of paper or board (multi layer), the outside liner was fluorescent, the centre or core layer showed low or 'patchy' fluorescence, and the inner liner which may come into contact with the food usually showed no fluorescence.

Interpretation

Unlike many substances which might migrate from food contact materials into food, FWAs are more soluble in water than in fat. Therefore, the situations where migration would probably occur include contact with moist foods, particularly at high temperatures. Specific examples of such conditions are tea bags and coffee filters, but FWAs were not detected in these materials. FWAs were either present at low levels or not detected in many of the samples which may come into contact with moist or fatty foods. The highest concentrations of FWAs were found in packaging for take-away food. In these cases a sample including all layers of the packaging was analysed for FWAs. Visual examination of the containers under UV light showed a greater intensity of fluorescence in the outer layer of the container than the inner layer which would be in contact with food. This indicates a greater concentration of FWAs in the outer layer, which would contribute to the high levels found on analysis. In addition the short time that the take-away food would be in contact with the packaging would also restrict migration.

The high level of fluorescence in the outer layer of the samples is expected as FWAs are used to improve the visual impact of paper and board. The 'patchy' fluorescence in the core layer of multi-layer board may indicate the use of recycled fibres from paper which contained FWAs.

FWAs are widely used in paper and board used in contact with food, however, their use in applications where conditions may encourage migration, such as contact with hot' moist or fatty foods, seem to be limited. For example, FWAs were not detected in tea bag tissue or coffee filters.

The limited toxicological information available on specific types of FWA has indicated the levels that could be present in the food would not cause a risk to human health, even if all the FWAs migrate into food from the samples in which the highest levels were detected. Also, in practice only a small proportion of the FWAs would be expected to migrate, therefore reducing the levels of FWAs that might be found in food

Contact point

Further information on this project can be obtained from:

Mr Patrice Monglard
MAFF, Joint Food Safety and Standards Group
Additives and Novel Foods Division
Room 213, Ergon House, c/o Nobel House
17 Smith Square
London, SW1P 3JR

Tel. No. + 44 (0)20 7238 6225
Fax. No. + 44 (0)20 7238 5331

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These pages were last updated on 1 October 1996