Number 90 May 1996
MAFF UK - SURVEY OF PAPER AND BOARD FOOD CONTACT MATERIALS FOR RESIDUAL
AMINE MONOMERS FROM WET STRENGTH AGENTS
Index to MAFF UK Food Surveillance Information
Sheets, 1996
see also:
1: MAFF UK -
Metallic Compounds in Plastics (July 1993)
15: MAFF UK - Hydrocarbons in Chocolate
(October 1993)
25: MAFF UK -
Compositions of Films Used to Wrap Foods (Feburary 1994)
26: MAFF UK - Formaldehyde in Tea-Bag Tissue
(May 1994)
35: MAFF UK - Survey of
Benzene in Food Contact Plastics (September 1994)
38: MAFF UK - Survey of Styrene in Food
(October 1994)
47: MAFF UK -
Fluorescent Whitening Agents (January 1995)
59: MAFF UK - Dioxins in PVC Food Packaging
(April 1995)
60: MAFF UK -
Phthalates in Paper and Board Packaging (May 1995)
66: MAFF UK - Grease Proofing Agents in
Paper and Board (June 1995)
72: MAFF UK - Curing Agents in
Carton-Board Food Packaging (July 1995)
139: MAFF, UK - Survey of Pentachlorophenol
in Paper and Board Packaging used for Retail Foods (December 1997)
169: MAFF, UK - Diisopropylnaphthalenes in
Food Packaging Made From Recycled Paper and Board (January 1999)
174: MAFF, UK - Survey of Retail Paper and
Board Food Packaging Materials for Polychlorinated Biphenyls (PCBs)
Summary
Central Science Laboratory (Norwich) has carried out a survey for MAFF Food
Safety Directorate to determine the levels of extractable amine monomers from
260 retail samples of paper and board food contact materials. The food contact
materials tested were tea bags, coffee filters, meat and fish pads, kitchen
towel and packaging for frozen foods and use in microwave ovens. Tea bag tissue
and coffee filters were immersed in boiling water to simulate migration. Other
materials were extracted with hot and/or cold water depending on their intended
uses. The results are reassuring. None of the five amine monomers studied was
detected in extracts or migration solutions. The amine monomers examined were:
ethylenediamine (EDA) and hexamethylenediamine (HMDA) (detection limits: 0.05
mg/l) and diethylenetriamine (DETA), N-(2-aminoethyl)-1,3-propanediamine (APDA)
and melamine (detection limits: 0.1mg/l).
Background
The survey reported here was conducted to investigate whether residual amine
monomers, from wet strength agents, migrated into water from a range of typical
paper and board food contact materials under simulated normal conditions of use.
Wet strength agents are added to paper and board to prevent these materials
weakening on contact with water.
The two major types of wet strength agents used in the UK are polyamide
resins and melamine-(1)formaldehyde (M-F) resins. Urea-formaldehyde (U-F)
resins are used occasionally. The amine monomers present in M-F and U-F resins
are melamine and urea respectively, whilst DETA, APDA, HMDA and EDA are found in
polyamide resins. The resins cross-link cellulose fibres, as they are being
cured, to form a mesh which binds together the paper or board. Incomplete
curing may give rise to residues of free amine monomer in paper or board. HMDA
and APDA are also used to produce retention aids which enhance dispersion of
substances in the paper pulp and promote take-up of fibres, fines, fillers and
other components onto the paper-making web.
Method
Paper and board samples were screened to determine whether they had been
treated with polyamide, M-F or U-F resins. The screening procedure used a
chromotropic acid test with a subsequent test to discriminate between U-F and
M-F resins. A schematic diagram of the screening procedure is shown in
Figure 1. After screening, extracts and migration
solutions were prepared from the food contact materials and analysed for amine
monomers. High performance liquid chromatography (HPLC) was used for melamine,
and gas chromatography-mass spectrometry (GC-MS) (based on the draft CEN method
for EDA 1) for the
other amines.
Results and Interpretation
Screening for resin type
M-F resins were found in 30 percent of the samples of food contact materials
tested, whilst U-F resins occurred in only 4 percent of samples which is
consistent with their occasional use as noted above. For the purpose of
subsequent analysis (Figure 1), samples were assumed to
be treated with polyamide resins if the chromotropic acid test proved negative.
This assumption was based on information from manufacturers that most, if not
all, the food contact materials in the survey were likely to have been treated
with wet strength agents.
Figure 1: The Screening Procedure
Analysis for amines
None of the five amine monomers was detected in any of the migration
solutions or extracts from paper and board samples. The detection limits are
well within the Specific Migration Limits (SMLs) for four of the amines that are
given in EC Directive 90/128/EEC (relating to plastics materials and articles
intended to come into contact with foodstuffs). It should be noted, however,
that the SMLs apply to food contact plastics and in relation to paper and board
they can only be used as guideline limits. The detection limits were 0.05 mg/l
for EDA and HMDA and 0.1mg/l for DETA, APDA and melamine, for the procedure used
in this study. These detection limits were at least an order of magnitude less
than the SMLs of 12 mg/kg and 2.4 mg/kg for EDA and HMDA respectively, and 5
and 30 mg/kg for DETA and melamine respectively. No SML has been set for APDA.
Conclusions
None of the 260 paper and board food contact materials tested was found to
contain detectable levels of residual free amine monomers. The results are
reassuring.
Reference
- CEN TC 194/SC 1 draft method: Determination of
ethylenediamine in food simulants.
Contact Point
For further information, please contact:
Dr David Watson,
MAFF, Food Safety and Science Group
Food
Contaminants Division,
Branch B, Room 212,
Ergon House,
17
Smith Square,
London SW1P 3JR
Tel: +44 (0)171 238 6226
Fax: +44 (0)171 238 5331
A copy of the full report is held in the Library, MAFF, Nobel House, 17
Smith Square, London SW1P 3JR.
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