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MAFF UK - SURVEY OF PENTACHLOROPHENOL IN PAPER AND BOARD PACKAGING USED FOR RETAIL FOODS

Index to MAFF UK Food Surveillance Information Sheets, 1997

Summary

A survey was carried out for the Ministry MAFF to see if the wood preservative pentachlorophenol (PCP) was present in retail paper and board food contact materials, mainly packaging, (limit of detection: 2 to 8 micrograms per kilogram), and, if detected, to test if this substance had migrated from the packaging into the food (limit of detection: 10 micrograms per kilogram). Three successive sets of materials were analysed in this three part survey. In the first part of the survey, 403 samples of paper and board food contact materials were bought from retail outlets between June 1996 and January 1997. PCP was detected at low levels in 36 of these samples. All but 4 of these 36 samples were of board. In the second part of the survey, a further 9 samples of the commodities whose packaging had the highest levels of PCP were purchased, between October 1996 and March 1997, and the packaging analysed to help further identify the highest levels of PCP. Finally, in the third part of the survey, 5 samples of commodities whose packaging material consistently contained the highest levels of PCP, in the first and second parts of the survey, were purchased in June and July 1997. The foods in these 5 samples were analysed, and no PCP was detected (limit of detection: 10 micrograms per kilogram).

Background

Residues of PCP in animal products as a result of the use of wood products in agricultural production have been investigated from time to time by the Working Party on Pesticide Residues.^1,^2,³ However, this is the first MAFF survey on the possible contamination of food by PCP from food contact materials.

The Materials and Articles in Contact with Food Regulations 1987, SI 1987 No. 1523, includes the general requirement that all materials and articles intended to come into contact with food should not transfer their constituents to food in quantities which could endanger health. This requirement applies to paper and board but there are no additional specific regulations covering these materials. Specific provisions for paper and board used in food contact applications are being developed by the Council of Europe and these may in due course form the basis of an EC Directive.

Methodology

The method of analysis involved steam distillation of PCP from the packaging using 2,3,6-trichlorophenol (TCP) as an internal standard, followed by the derivatisation of PCP with acetic anhydride to form PCP acetate. Analysis of PCP acetate was by gas chromatography with electron capture and finally with mass spectrometric detection. This method for the determination of PCP has been proposed by Technical Committee 172 of the European Committee for Normalisation (CEN/TC172).

Where the sample was a paper or board already in contact with food, the food was removed from the packaging as soon as possible after purchase. The packaging was wrapped in aluminium foil and stored at room temperature, except where there was significant contamination of the packaging by the food (e.g. in meat pads) in which case the packaging was stored at -20°C until analysis. The food was generally discarded except when samples were purchased specifically for food analysis because the packaging had been found to contain PCP.

For packaging analysis, every analytical batch contained ten samples, one method blank and one spiked sample. Care was taken to include paper or board samples of similar types in each batch. Recovery ranged from 62 to 124 per cent. The results presented here are corrected for the batch recovery. For the analysis of the food samples, four samples of each food were analysed - three replicate food portions and one food portion which was spiked. The analytical recovery of the spiked sample was rather low because the food matrix suppressed the volatilisation of PCP in the steam. Nevertheless, the recovery from food was relatively constant at 21 to 34 per cent and the target limit of detection of 10 micrograms per kilogram was achieved. Results for food analysis were corrected for recovery for corresponding spiked samples.

In the first part of the survey 403 packaging samples were analysed for PCP. The samples were of food packaging (70 per cent), take-away packaging (20 per cent) and cooking papers (10 per cent - grease-proof paper, cake cases, ovenable trays, microwave bags and susceptors). Samples were purchased mainly in East Anglia and Leeds in equal batches between June 1996 and January 1997. Purchases were from national supermarkets and other shops, reflecting market share. A full list of samples is given in Table 1A.

The samples were analysed initially as composites of 5 individual samples, i.e. samples were pooled together to form a single sample for extraction. If the concentration of PCP exceeded 20 micrograms per kilogram in the composite, this indicated that one or more of the samples could contain PCP in excess of 100 micrograms per kilogram, and the constituent samples in the composite were then analysed individually. This limit of 100 micrograms per kilogram, which is a draft purity requirement proposed by the Council of Europe, was used as a guide on whether to analyse individual samples of packaging.

Nine samples of the food products whose packaging contained the highest levels of PCP, following individual analyses, were purchased between October 1996 and March 1997 and the packaging was analysed in the second part of the survey. These 9 samples were from different batches than the original samples (Table 1B).

A third set of 5 samples, where the packaging in the corresponding first and second sets of samples had in both parts of the survey contained PCP at or above 100 micrograms per kilogram, was purchased in June and July 1997. These 5 samples were from different batches than those in the first and second parts of the survey. Both the packaging and the food from the third set of samples were then analysed for PCP.

Results and Interpretation

The details for each of the samples purchased in the first part of the survey, including brand names, are reported in Table 1A. PCP was detected in 36 individual paper and board packaging samples, at levels of above 8 micrograms per kilogram, and in 13 samples, all of board, the levels exceeded 100 micrograms per kilogram (Table 2). The limit of detection was 2-8 micrograms per kilogram depending on the day-to-day sensitivity of the instrumentation used.

The results for the second and third parts of the survey are given in Table 1B and Table 1C, respectively. PCP was detected in all 9 samples in the second part of the survey. The levels found were, except for one sample, lower than for the corresponding samples in the first part of the survey (Table 3). In 4 of the samples the level of PCP exceeded 100 micrograms per kilogram and a further 2 samples contained more than 80 micrograms per kilogram.

Packaging from the 5 samples purchased in the third part of the survey was again found to contain PCP, but the foods contained in this packaging did not contain any detectable PCP (Table 3).

As the samples in the three successive parts of the survey were purchased over a period of 13 months and came from different batches the presence of PCP is unlikely to be due to a single instance of contamination.

Conclusions

The levels of PCP identified in packaging in this survey do not pose a risk to health because no migration into food was detected using a very sensitive method of analysis. Even though only 5 samples of foods were analysed, these samples were targeted as their packaging contained the highest levels of PCP.

Detection of the highest levels of PCP in different batches of board suggests that the presence of PCP is not random, but is probably linked to the type of packaging and the raw materials used.

References:

MAFF/HSE (1993). Annual Report of the Working Party on Pesticide Residues: 1992. Supplement to the Pesticides Register 1993. HMSO.
MAFF/HSE (1994). Annual Report of the Working Party on Pesticide Residues: 1993. Supplement to the Pesticides Register 1994. HMSO.
MAFF/HSE (1995). Annual Report of the Working Party on Pesticide Residues: 1994. Supplement to the Pesticides Register 1995. HMSO.

Contact point

The report of the survey is held in the MAFF Library at Nobel House, 17 Smith Square, London SW1P 3JR (Tel: +44 (0) 171-238-6573).

Further enquiries should be addressed to:

Dr David Watson
Branch B
Additives and Novel Foods Division
Room 212, Ergon House
17 Smith Square
London SW1P 3JR

Tel: +44 (0) 171 238 6250
Fax: +44 (0) 171 238 6124

Spreadsheet Tables

Table 1A: List of samples purchased for analysis in first part of survey
Click here to download the Excel version of Table 1A
Shift-Click here to download the .csv version of Table 1A (if you have any other spreadsheet package)

Table 1B: List of samples purchased for analysis in second part of survey
Click here to download the Excel version of Table 1B
Shift-Click here to download the .csv version of Table 1B (if you have any other spreadsheet package)

Table 1C: List of samples purchased for analysis in third part of survey
Click here to download the Excel version of Table 1C
Shift-Click here to download the .csv version of Table 1C (if you have any other spreadsheet package)

Table 2: Packaging samples containing PCP at or above 8 micrograms per kilogram in the first part of the survey
Click here to download the Excel version of Table 2
Shift-Click here to download the .csv version of Table 2 (if you have any other spreadsheet package)

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These pages were last updated on 30th November 1997