Migration of Mineral Oil into Noodles from Recycled Fibres in the Paperboard Box and the Corrugated Board Transport Box as well as from Printing Inks: A Case Study

From the toxicological evaluation of mineral oils as used in offset printing inks by the Joint Food and Agriculture Organization of the United Nations/World Health Organization Expert Committee on Food Additives (JECFA), a specific migration limit of 0.6 mg/kg in food can be derived. Experimental packs for taglioline (fine noodles) were investigated, aiming at respecting this limit. This ended with four conclusions. First, during the 65 day test (shelf life of 2 years), the transport box of corrugated board contaminated the bottom packs in the box with 6.1 mg/kg mineral oil saturated hydrocarbons (MOSH) and had the potential of contaminating all the 10 packs on average at about 10 mg/kg. Second, the migration from an improved recycled paperboard (five times less mineral oil than average) still amounted to 4.9 mg/kg, indicating that optimization of recycling is not promising to respect the 0.6 mg/kg limit. Third, a printing ink containing 3 g/kg MOSH (about 100 times less than conventional offset inks) still contaminated the taglioline with 0.6 mg/kg MOSH. Finally, the taglioline were contaminated with 2.5 mg/kg MOSH already before packing, illustrating that there are other sources of mineral oil violating the 0.6 mg/kg limit. Copyright © 2011 John Wiley & Sons, Ltd.     

Nuclear reaction analysis of helium migration in silicon carbide

4H-SiC and 6H-SiC single crystals were implanted at room temperature with 3-MeV ³He ions at a fluence of 1 × 10¹⁶ cm⁻². Analysis of helium migration was carried out with the ³He(d, p)⁴He nuclear reaction. No clear thermally-activated migration in the end-of-range (EOR) region is found below 1100 °C, meaning that helium is strongly trapped probably in helium-vacancy clusters. At 1100 °C and above, a fraction of ³He atoms remains trapped in the clusters, but a significant fraction is detrapped into a broad distribution, which is slightly shifted towards the sample surface. Helium detrapping from the EOR region increases with increasing annealing time and temperature. Moreover, the helium content is not conserved, since a significant fraction of ³He atoms is released out of the sample. Helium out-gassing actually increases with increasing annealing time and temperature, up to about 40% at 1150 °C. No clear difference is found between the 4H-SiC and 6H-SiC polytypes.     

Enrichment for reducing the detection limits for the analysis of mineral oil in fatty foods

A German draft for a regulation requires that there must be no migration of mineral oil aromatic hydrocarbons (MOAH) from recycled paperboard into food. The Federal Institute for Risk Assessment (BfR) is requested to establish the detection limit. It was previously shown that the detection limit of the commonly used methods is below 0.1 mg/kg for the majority of the foods, but substantially higher in fatty products because of limited capacity of the liquid chromatographic preseparation to retain fat, interference by olefins and, if also the mineral oil saturated hydrocarbons (MOSH) should be analyzed, the natural paraffins primarily consisting of odd-numbered n-alkanes. A method is described for the enrichment of the MOSH and MOAH conceived as an auxiliary tool for fatty foods analyzed by the conventional methods, such as on-line HPLC–GC. In a double bed liquid chromatographic column, the lower packing consists of a mixture of activated aluminum oxide, silica gel with silver nitrate and activated silica gel, the upper of activated silica gel. The technical detection limit in edible oils is below 0.3 mg/kg, which translates to less than 0.1 mg/kg in the dry foods packed in recycled paperboard. The distinction between migrated mineral oil and that present before packaging often presupposes the availability of the food prior to packaging.     

Assurance of compliance within the production chain of food contact materials by good manufacturing practice and documentation – Part 3: Lids for glass jars as an example

Parts 1 and 2 of this work outlined the background and the general terms of assuring compliance of food contact materials (FCM) with European legislation by good manufacturing practice (GMP) and compliance declaration (CD). All stages of the manufacturing process are engaged in GMP defined as the process to achieve compliance of the final product with Article 3 of the Framework Regulation 1935/2004 and the specific legislation derived there from. For each relevant aspect, either compliance is concluded (explicitly stating compliance if this is required) or compliance work is delegated to later stages of manufacturing by corresponding instructions in the documentation accompanying the product. A compliance box (CB) is proposed to structure the process and the documentation. Here it is applied to metal closures for glass jars, which are internally coated and contain a gasket of plasticized PVC. A specific composition is assumed and possible compliance work discussed to illustrate how the system is conceived. The system is tested by the problems and issues concerning these lids during the last 10 years: indeed, most of them would have been avoided.     

ZnTe precipitates formed in SiO2 by sequential implantation of Zn and Te ions

Ion implantation is a versatile tool for the formation of compound semiconductor nanocrystal precipitates in a host medium with the ultimate goal to form quantum dots for use in device technology. Low dose (1 × 10¹⁶ cm⁻²) implantations of tellurium and zinc ions have been performed in a 250 nm thick SiO₂ layer thermally grown on 1 1 1 silicon. Their respective energies (180 and 115 keV) have been chosen to produce 5–10 at.% profiles overlapping at a mean depth of about 100 nm. Subsequent thermal treatments at 700 and 800 °C lead to the formation of nanometric precipitates of the compound semiconductor ZnTe. Their size, crystalline structure and depth distribution have been studied as a function of annealing temperature using transmission electron microscopy (TEM) and Rutherford backscattering spectrometry. For the lowest temperature the TEM images shows a cloudy band of ZnTe, but for the highest temperature, the ZnTe nanocrystals are self organized into two layers parallel to the surface. Their mean diameter ranges between 4 and 30 nm, as a function of annealing temperature.     

Saturated and aromatic mineral oil hydrocarbons from paperboard food packaging: estimation of long-term migration from contents in the paperboard and data on boxes from the market

In the absence of a functional barrier, mineral oil hydrocarbons from printing inks and recycled fibres tend to migrate from paper-based food-packaging materials through the gas phase into dry food. Concentrations easily far exceed the limit derived from the acceptable daily intake (ADI) of the Joint FAO/WHO Expert Committee on Food Additives (JECFA). Since the estimation of long-term migration into the food by testing at 40°C for 10 days is difficult, it seems preferable (and easier) to use the mineral oil content in the paperboard. Evaporation experiments showed that hydrocarbons eluted up to about n-C?? are sufficiently volatile for relevant migration into dry food: in worst-case situations, about 80% migrate into the packed food. The extraction of the paperboard was optimised to give good recovery of the relevant hydrocarbons, but to discriminate against those of high molecular mass which tend to disturb gas chromatographic analysis in on-line coupled normal phase HPLC-GC-FID. Even though some of the relevant hydrocarbons had already evaporated, the average concentration of < C?? mineral oil saturated hydrocarbons (MOSH) in the paperboard boxes of 102 products from the Swiss and Italian market was 626 mg kg?1. Nearly 15% of investigated boxes still contained more than 1000 mg kg?1 < C?? MOSH up to over 3000 mg kg?1 (maximum = 3500 mg kg?1). This amount of MOSH in the board have the potential of contaminating the packed food at a level exceeding the limit, derived from the JECFA ADI, hundreds of times.     

Epoxidized soy bean oil (ESBO) migrating from the gaskets of lids into food packed in glass jars

Epoxidized soy bean oil (ESBO) was determined in foods packed in glass jars closed by lids with a poly(vinyl chloride) (PVC) gasket. The methyl ester of a diepoxy linoleic acid isomer was measured, using transesterification directly in the homogenized food and on-line HPLC-GC-FID analysis. Infant foods from the Swiss market consisting of vegetables, potato and rice or muesli with fruits and berries contained less than 7 mg/kg ESBO, but meat (its fat?) strongly increased ESBO migration up to 86 mg/kg. Some 12% of the products exceeded 15 mg/kg. Austrian and Norwegian samples gave similar results. Edible oil strongly extracts the ESBO from the gasket in food contact within a few weeks. Since this part of the gasket on average contained 91 mg ESBO, the legal limit is likely to be far exceeded whenever the food contains free oil contacting the gasket, such as oily sauces or vegetables and fish in oil. In fact, the mean ESBO concentration in 86 samples was 166 mg/kg, with a maximum of 580 mg/kg.     

How much reducing sugar may potatoes contain to avoid excessive acrylamide formation during roasting and baking?

For many consumers, potatoes fried or roasted in professional or private kitchens are the most important source of exposure to acrylamide. Acrylamide formation can be reduced by appropriate preparation techniques, but suitable potatoes are a prerequisite. The tendency of potato to form acrylamide can be approximated by the content of reducing sugar. Roast potatoes (hash browns, Rösti) and oven-fried potatoes (Bratkartoffeln) were prepared to optimum culinary quality regarding crispiness and then evaluated in terms of browning, roasting flavor and acrylamide content. Preparation procedures were optimized to produce a minimum of acrylamide. It is concluded that potatoes with less than 0.2 g/kg fresh weight fructose and glucose are not suitable for roasting (insufficient browning and flavor), while roasted products of minimum crispiness prepared from potatoes with more than 1 g/kg reducing sugar contain more than 500 µg/kg acrylamide. It is proposed that potatoes which may be used for roasting and frying should contain less than 1 g/kg fresh weight of reducing sugar. This can easily be fulfilled with the most important potato cultivars grown in Switzerland, but presupposes that potatoes are no longer stored at 4 °C.     

Food contamination by hydrocarbons from packaging materials determined by coupled LC-GC

Paraffins from raw extracts of foods and packing materials were isolated by LC and directly transferred to GC, applying concurrent eluent evaporation and a loop-type interface. Paraffins from various packing materials have been characterized: sisal bags, cardboard boxes, plastic films, wax-coated paper and cardboard as well as paraffin coatings. Important food contamination was found for sisal bags, cardboard boxes, and wax-coated paper/cardboard. Contamination by paraffin coatings on cheese was surprisingly small.