A03033: Investigation of chemical migration into take-away foods

Study Duration: May 2001 to November 2003

Contractor: Central Science Laboratory

Take-away foods are considered to be 'foods packaged immediately prior to sale and consumed off the premises shortly thereafter'. Snack foods are considered to be 'foods designed to be eaten with fingers, not sweetened (confectionery) and not heated (take-away), without further preparation, and usually direct from the packaging'. From a migration perspective, take-away foods assume special importance due to the relatively large packaging usage and their conditions of use, the majority of take-away foods being served hot which may accelerate any chemical migration. Snack foods are generally associated with a large packaging volume (high contact area:mass of food ratio). In addition many snack foods have a high fat content and thus the migration of any lipophilic substances from the packaging into the snack food could be increased.

The objective of this project is to test if there is any chemical migration from the packaging used for take-away and snack foods. Where potential chemical migrants are identified the worst case migration potentials into foods and the associated exposure values are calculated. For any substances where the calculated worst case migration potential and/or exposure values are found to be in excess of any restrictions in place then the migration into foods is determined.

Matched-pairs of 30 take-away foods are to be purchased, with one sample in the intended packaging and the second supplied directly into aluminium foil (food) or glass (beverages). Although logistically complicated, this approach ensures that the packaged sample is a true representation of commercial practice and does not rely on simulation tests in the laboratory. Additionally, samples of empty, unused packaging material will be obtained from the vendors. Analysis of the packaging materials, the control food samples and the packed food samples allow firm conclusions to be drawn as to the nature and extent of any chemical migration that occurs. Forty snack foods are to be purchased. Screening analysis of all packaging materials by headspace gas chromatography-mass spectrometry (GC-MS), liquid extraction followed by GC-MS and liquid extraction followed by liquid chromatography-mass spectrometry (LC-MS) is used to identify potential migrants. The worst case migration potential and the worst case exposure are calculated for all substances detected applying the conventional area: mass food contact ratio as well as the actual food contact ratio for the products. The results of the calculations are then compared with the specific migration limit for substances derived from plastics or the Acceptable Daily Intake / Tolerable Daily Intake or other exposure restrictions assigned, for substances from non-plastics.

For the take-away foods, calculations showed that the migration of ethylbenzene from polystyrene packaging materials had the potential to exceed the specific migration limit (SML). However, measurable levels of ethylbenzene were detected in only one of the foods at a level of 1 part per billion (ppb) which is much less than the SML of 600 ppb. Similarly, relatively high levels for the worst case migration potential for styrene were calculated. At present there is no SML for this substance, however, migration studies were undertaken on foods. Low levels of styrene were measured in some of the foods but in all cases were less than 5 ppb. Other potential migrants were identified in both the take-away and the snack food packaging, the majority of which derived from the printing inks applied to the outside of the packaging. When applying the conventional food contact ratio the worst case potential exposure did not exceed restrictions assigned for any of the substances in any of the products. However, for the snack foods, when the actual food contact ratio was applied the exposure restrictions for some compounds could theoretically be exceeded. The concentrations of these substances were determined in foods and the exposure calculated. Of the four substances tested for, only one, dicyclohexyl phthalate, was detected in one of the foodstuffs, at a concentration of 0.60 milligram (mg)/kilogram (kg). This equates to an exposure of 0.010 mg/kg body weight, using the conventional EU approach to assessing exposure of migrants from food contact materials of using an intake of 1 kg of packaged food per 60 kg person per day. The temporary tolerable daily intake of this substance is 0.10 mg/kg body weight.

Despite the high contact temperatures between take-away foodstuffs and packaging and the relatively high packaging area : mass of food ratio for snack foods, the migration levels observed were low. The majority of the potential migrants detected were associated with the printing inks on the outside of the packaging material, which itself may have provided a barrier to reduce migration. All of the snack foods analysed were rigid or semi-rigid solids, which did not make complete and intimate contact with the entire surface of the packaging material. Consequently, even where potential migrants were present at comparatively high levels in the packaging of the snack foods the levels migrating into the foodstuffs were reassuringly low.

Final report is available from the FSA Library and Information centre.
To obtain a copy, please contact the Enquiry Desk, Dr. Elsie Widdowson Library and Information Services, Food Standards Agency (020 7276 8181/8182 or at library&info@foodstandards.gsi.gov.uk).

Contact: For any enquiries concerning this research project, please contact the relevant Programme contact or email science@foodstandards.gsi.gov.uk