Comparison of migration from polyethersulphone and polycarbonate baby bottles

This work presents two analytical methods developed for measuring three components of polyethersulphone (PES) and applying them to the migration testing of 30 baby bottles made of PES. The study also provides migration results under the same conditions for bisphenol A (BPA) from 40 polycarbonate baby bottles using a well-established method adapted to low concentrations. For PES bottles, migration of diphenyl sulphone (DPS), 4,4′-dichlorodiphenyl sulphone (DCPS) and 4,4′-dihydroxydiphenyl sulphone (DHPS; also known as bisphenol S) was carried out using two different analytical methods with detection limits of 0.1–0.3?µg/kg, and, therefore, much below their respective European Commission Directive 2002/72/EC legislative migration limits of 50–3000?µg/kg, respectively. In parallel, 40 bottles made of polycarbonate were analysed for the migration of BPA using a method validated at EU level and modified to give a lower detection limit of 0.1?µg/kg. Migration tests were conducted into the simulant for milk 50% EtOH (as per Commission Regulation No. 321/2011 of 1 April 2011) according to the test conditions from the guidelines on test conditions for articles in contact with foodstuffs (with a focus on kitchenware) prepared by the EU Reference Laboratory and its network of National Reference Laboratories. None of the 30 bottles made of PES released any detectable amounts of DCPS or DHPS and only two bottles released a very low amount of DPS of ～1?µg/kg in the milk food simulant compared to a regulatory limit of 3000?µg/kg. For PC bottles, 32 bottles of 40 (80%) did not release BPA above the LOD of 0.1?µg/kg (in any of the three migration tests performed on each bottle). The other 20% of bottles exhibited only very minor migration, where the highest level in the first migration test was 1.83?µg/kg and most bottles did not release detectable BPA in the second and third test. Only one bottle, with a migration level of 1.08?µg/kg, in the first test still showed a detectable level in the last migration test (i.e. 0.42?µg/kg). It is important to note that the legal limit (European Commission Directive 2002/72/EC) was still 600?µg/kg for polycarbonate bottles at the time of purchase, preceding the precautionary ban taking effect from 1 June 2011 (Commission Directive 2011/8/EU; Commission Regulation No. 321/2011). This confirms that the likelihood of migration of BPA is very low and remains at very minute amounts. The results also suggest the absence of release from PES bottles based on the set of bottles investigated.     

Migration of bisphenol A from plastic baby bottles,baby bottle liners and reusable polycarbonate drinking bottles

Human exposure to bisphenol A (BPA) has recently received special attention. It has been shown that exposure to BPA may occur through the consumption of beverages or foods that have been in contact with polycarbonate (PC) plastic containers or epoxy resins in food packaging. A BPA migration study was conducted using a variety of plastic containers, including polycarbonate baby bottles, non-PC baby bottles, baby bottle liners, and reusable PC drinking bottles. Water was used to simulate migration into aqueous and acidic foods; 10% ethanol solution to simulate migration to low- and high-alcoholic foods; and 50% ethanol solution to simulate migration to fatty foods. By combining solid-phase extraction, BPA derivatization and analysis by GC-EI/MS/MS, a very low detection limit at the ng l^?1 level was obtained. Migration of BPA at 40°C ranged from 0.11 µg l^?1 in water incubated for 8 h to 2.39 µg l^?1 in 50% ethanol incubated for 240 h. Residual BPA leaching from PC bottles increased with temperature and incubation time. In comparison with the migration observed from PC bottles, non-PC baby bottles and baby bottle liners showed only trace levels of BPA. Tests for leachable lead and cadmium were also conducted on glass baby bottles since these represent a potential alternative to plastic bottles. No detectable lead or cadmium was found to leach from the glass. This study indicated that non-PC plastic baby bottles, baby bottle liners and glass baby bottles might be good alternatives for polycarbonate bottles.     

Identification and quantification of the migration of chemicals from plastic baby bottles used as substitutes for polycarbonate

The results of a study on the analytical identification and quantification of migration of chemicals from plastics baby bottles found in the European Union market made of materials that are now present as substitutes for polycarbonate (PC) are reported. A total of 449 baby bottles with a focus on first age or sets of bottles were purchased from 26 European Union countries, Canada, Switzerland and the USA. From this collection, which contained several duplicates, a total of 277 baby bottles were analysed. The materials included different types of plastic such as PC, polyamide (PA), polyethersulphone (PES), polypropylene (PP), but also silicone, and from the United States a co-polyester marketed under the trade name Tritan?. The bottles were subjected to the conventional migration test for hot fill conditions, i.e. 2?h at 70°C. The simulant used was that specified in European Union legislation (2007/19/EC) for milk, i.e. 50% ethanol. In a first phase 1, migration was conducted since the scope of this investigation was a screening rather than a true compliance testing check. Second and third migrations were performed on selected articles when migrated substances exceeded limits specified in the legislation. In order to verify some materials, a portion of the bottle was cut to run an FT-IR fingerprint to confirm the nature of the polymer. The migration solutions in general showed a low release of substances. Results showed that bottles made of PP and silicones showed a greater number of substances in the migration solutions and in greater quantity. Chemicals from PP included alkanes, which could be found in >65% of the bottles at levels up to 3500?μg?kg?1; and benzene derivatives in 17% of the baby bottles and found at levels up to 113?μg?kg?1. Some substances were found on a regular basis such as plasticisers, esters and antioxidants (e.g. tris(2,4-di-tert-butylphenyl)phosphate, known as Irgafos 168. Some substances found were not included in the Community positive list, which means that those should not be found even in the first migration. Such substances included 2,6-di-isopropylnaphthalene (DIPN), found in 4% of the bottles at levels up to 25?μg?kg?1, 2,4-di-tert-butyl phenol (in 90% of the bottles at levels up 400?μg?kg?1). Moreover, bisphenol A (BPA) was detected and quantified in baby bottles made of PA, but limited to one brand and model specific (but labelled BPA free). Results for baby bottles made of silicone also indicated the presence of components, e.g. potentially coming from inks (benzophenone, diisopropyl naphtahalene - DIPN, which could come for example from the presence of instruction leaflets in the bottles). In the case of silicone, phthalates were also found in relevant concentrations, with levels for DiBP and DBP from the first migration test of 50-150?μg?kg?1 and DEHP at levels 25-50?μg?kg?1.     

Evaluation of the migration of chemicals from baby bottles under standardised and duration testing conditions

After the prohibition of bisphenol-A-containing polycarbonate baby bottles in the European Union (EU), alternative materials, such as polypropylene, polyethersulphone, Tritan? copolyester, etc., have appeared on the market. Based on an initial screening and in vitro toxicity assessment, the most toxic migrating compounds were selected to be monitored and quantified using validated GC- and LC-QqQ-MS methods. The effect of several ‘real-life-use conditions’, such as microwave, sterilisation and dishwasher, on the migration of different contaminants was evaluated by means of duration tests. These results were compared with a reference treatment (filling five times with pre-heated simulant at 40°C) and with the legal EU ‘repetitive-use conditions’ (three migrations, 2 h at 70°C). Analysis of the third migration step of the EU repetitive-use conditions (which has to comply with the EU legislative migration limits) showed that several non-authorised compounds were observed in some baby bottles exceeding 10 µg kg^?1. However, all authorised compounds were detected well below their respective specific migration limits (SMLs). The reference experiment confirmed the migration of some of the compounds previously detected in the EU repetitive-use experiment, though at lower concentrations. Analysis of extracts from the microwave and dishwasher experiments showed a reduction in the migration during the duration tests. In general, the concentrations found were low and comparable with the reference experiment. Similar observations were made for the two sterilisation types: steam and cooking sterilisation. However, steam sterilisation seems to be more recommended for daily use of baby bottles, since it resulted in a lower release of substances afterwards. Repeated use of baby bottles under ‘real-life’ conditions showed no increase in the migration of investigated compounds and, after some time, the migration of these compounds even became negligible.     

Migration of bisphenol A from polycarbonate baby bottles under real use conditions

Migration of the potential endocrine disrupter, bisphenol A (BPA), from 31 polycarbonate (PC) baby bottles into aqueous food simulants was studied under real repetitive use, using a sensitive and fully validated liquid chromatographic method with fluorescence detection. Confirmation of the presence of BPA was performed by liquid chromatography–mass spectrometry (LC–MS). The effects of cleaning in a dishwasher or with a brush, sterilization with boiling water and the temperature of migration were examined. It was shown that temperature was the crucial factor for the migration of BPA from the plastic bottles to water. All samples released BPA in the concentration range 2.4–14.3 µg kg^?1 when filled with boiled water and left at ambient temperature for 45 min. The decrease of BPA release in the sterilization water and in the food simulant over 12 cycles of use indicated that the hypothesis of polymer degradation in water is dubious. Estimated infantile dietary exposure, regarding the use of PC baby bottles, ranged between 0.2 and 2.2 µg kg^?1 bw day^?1, which is below the Tolerable Daily Intake of 50 µg kg^?1 bw recently established by EFSA.     

Migration of bisphenol A from polycarbonate baby bottles purchased in the Spanish market by liquid chromatography and fluorescence detection

During the last decade the safety of bisphenol A (BPA) monomer in polycarbonate baby bottles has drawn the attention of both the public and the scientific community. This paper presents the results of BPA migration from polycarbonate baby bottles bought in the Spanish market, into simulant B (3% acetic acid), 50% ethanol and into real food (reconstituted infant formula). Furthermore, it was also the objective of this study to assess the suitability of 50% ethanol as a simulant for infant formula. BPA was analysed by a multi-analyte liquid chromatography method with fluorescence detection and mass spectrometry confirmation. The method was in-house validated and accredited by the national accreditation body. The validation results for this analyte in the previous mentioned matrices were: LOD?=?0.004–0.007?mg?kg^–1; LOQ (validated)?=?0.03?mg?kg^–1; RSD%?=?3.4–5.8; and recovery?=?106.6–118.2%. A collection of 72 different baby bottle samples from 12 different brands were analysed. Baby bottle material was identified by FTIR. The migration test conditions used were those recommended for baby bottles in the Guidelines on testing conditions for articles in contact with foodstuffs (with a focus on kitchenware), prepared by the European network of laboratories for food-contact materials. In most of the migration assays the results were below the LOD. In four of the commercial brands there was detectable migration into the simulant 50% ethanol and BPA was detected in only two samples of infant formula (0.01?mg?kg^–1). Migration results obtained were in compliance with European Union regulations.     

Migration of bisphenol A into water from polycarbonate baby bottles during microwave heating

A comprehensive migration database was established for bisphenol A from polycarbonate baby bottles into water during exposure to microwave heating. Eighteen different brands of polycarbonate baby bottles sold in Europe were collected. Initial residual content of bisphenol A and migration after microwave heating were determined. Residual content of bisphenol A in the polycarbonate baby bottles ranged from 1.4 to 35.3 mg kg^?1. Migration of bisphenol A was determined by placing a polycarbonate bottle filled with water in a microwave oven and heating to 100°C; the level of bisphenol A in the water was analysed by GC–MS. The procedure of microwave heating and analysis was repeated twice for the same bottle and, thus, three migration extracts were prepared for each test specimen. Migration of bisphenol A into water ranged from <0.1 to 0.7 µg l^?1. There was no correlation between the amount of residual content of bisphenol A in the bottles and the migration of bisphenol A into water. Furthermore, there was no correlation between the amounts of bisphenol A in consecutive migration extracts. Data show that during three microwave-heating cycles of a baby bottle made from polycarbonate, microwave radiation had no effect on the migration of bisphenol A into water from polycarbonate. All levels found were well below the specific migration limit of 0.6 mg kg^?1 specified for bisphenol A in Commission Directive 2004/19/EC.     

Development and application of a non-targeted extraction method for the analysis of migrating compounds from plastic baby bottles by GC-MS

In 2011, the European Union prohibited the production of polycarbonate (PC) baby bottles due to the toxic effects of the PC monomer bisphenol-A. Therefore, baby bottles made of alternative materials, e.g. polypropylene (PP) or polyethersulphone (PES), are currently marketed. The principal aim of the study was the identification of major compounds migrating from baby bottles using a liquid–liquid extraction followed by GC/MS analysis. A 50% EtOH in water solution was selected as a simulant for milk. After sterilisation of the bottle, three migration experiments were performed during 2 h at 70°C. A non-targeted liquid–liquid extraction with ethyl acetate–n-hexane (1:1) was performed on the simulant samples. Identification of migrants from 24 baby bottles was done using commercially available WILEY and NIST mass spectra libraries. Differences in the migrating compounds and their intensities were observed between the different types of plastics, but also between the same polymer from a different producer. Differences in the migration patterns were perceived as well between the sterilisation and the migrations and within the different migrations. Silicone, Tritan? and PP exhibited a wide variety of migrating compounds, whereas PES and polyamide (PA) showed a lower amount of migrants, though sometimes in relatively large concentrations (azacyclotridecan-2-one up to 250 µg kg^?1). Alkanes (especially in PP bottles), phthalates (dibutylphthalate in one PP bottle (±40 µg kg^?1) and one silicone bottle (±25 µg kg^?1); diisobutylphthalate in one PP (±10 µg kg^?1), silicone (up to ±80 µg kg^?1); and Tritan? bottle (±30 µg kg^?1)), antioxidants (Irgafos 168, degradation products of Irganox 1010 and Irganox 1076), etc. were detected for PP, silicone and Tritan? bottles. Although the concentrations were relatively low, some compounds not authorised by European Union Regulation No. 10/2011, such as 2,4-di-tert-butylphenol (10–100 µg kg^?1) or 2-butoxyethyl acetate (about 300 µg kg^?1) were detected. Migrating chemicals were identified as confirmed (using a standard) or as tentative (further confirmation required).     

Dietary exposure assessment of infants to bisphenol A from the use of polycarbonate baby milk bottles

The residual bisphenol A (BPA) levels in 28 different brands of polycarbonate (PC) baby milk bottles available in the Singapore market were measured. With a detection limit of 3 mg/kg, BPA residues were detected in 19 out of the 28 PC baby milk bottles at levels between 4.01 and 141 mg/kg, with a mean of 28.1 ± 31.4 mg/kg and a median of 17.2 mg/kg. The potential migration of BPA from each of the 28 PC milk bottles was also measured using food-simulating solvents and time conditions recommended by the US Food and Drug Administration (US FDA), but using temperatures more severe than actual use. The highest upper-bound mean BPA migration levels of 0.64 ± 0.48 µg/in² in 10% ethanol at 70°C and 0.43 ± 1.25 µg/in² in corn oil at 100°C were observed after incubating cut portions of the milk bottles for 240 h. With this migration data and using US FDA's procedure for estimation of dietary exposure, the worst-case dietary exposure assessment for the intake of BPA by infants between birth and three months of age was below the oral Reference Dose of 0.05 mg/kg bw/day established by the US Environmental Protection Agency. This study showed that the dietary exposure to BPA from actual uses of PC milk bottles is unlikely to pose a health risk in infants.     

Primary aromatic amine migration from polyamide kitchen utensils: method development and product testing

A rapid and sensitive LC-MS/MS method for the identification, quantification and confirmation of six primary aromatic amines (PAAs) was developed and validated to ISO 17025:2005. From a literature survey, 57 frequently used PAA compounds were identified and subsequently reduced to six – aniline, 4,4′-MDA, 3,3′-DMB, 2,4-TDA, 2,6-TDA and o-T – based on results from migration studies on a range of utensils. Low LOQs of between 0.075 and 0.496?µg?l^?1 were determined for the six analytes, thereby quantifying well below the legal limit of 10?µg?kg^?1 total PAAs. Furthermore, low measurement uncertainties were calculated for the analytical method, in the range of 3.15–3.20%. Mean recoveries were between 98% and 102% and spanned over ±12% at 95% CI. Following the analysis of 84 black polyamide kitchen utensils, the migration of PAAs detected was significant and is therefore of concern. The six analytes identified, quantified and confirmed in this survey could be utilised as possible markers for the identification of PAA migration, thereby improving the time and cost-efficiency of food control laboratories.     

Mycotoxin co-occurrence in rice,oat flakes and wheat noodles used as staple foods in Ecuador

The co-occurrence of aflatoxin B₁ (AFB₁), B₂ (AFB₂), G₁ (AFG₁) and G₂ (AFG₂), ochratoxin A (OTA), deoxynivalenol (DON), fumonisin B₁ (FB₁), zearalenone (ZEN), and HT-2 and T-2 toxins in the main Ecuadorian staple cereals (rice, oat flakes, and yellow and white wheat noodles) was evaluated. A ultra high performance liquid chromatography/time-of-flight mass spectrometry (UHPLC/TOFMS) method was developed and validated to screen for the presence of these mycotoxins in those cereal matrices. Matrix-matched calibration curves were used to compensate for ion suppression and extraction losses and the recovery values were in agreement with the minimum requirements of Regulation 401/2006/EC (70–110%). For most mycotoxins, the LODs obtained allowed detection in compliance with the maximum permitted levels set in Regulation EC/2006/1881, with the exception of OTA in all cereals and AFB1 in yellow noodles. Extra target analysis of OTA in oat flakes and wheat noodles was performed by HPLC with fluorescence detection. High rates of contamination were observed in paddy rice (23% DON, 23% FB₁, 7% AFB₁, 2% AFG₁ and 2% AFG₂), white wheat noodles (33% DON and 5% OTA) and oat flakes (17% DON, 2% OTA and 2% AFB₁), whereas the rates of contamination were lower in polished rice (2% AFG₁ and 4% HT-2 toxin) and yellow noodles (5% DON). Low rates of co-occurrence of several mycotoxins were observed only for white wheat noodles (5%) and paddy rice (7%). White noodles were contaminated with DON and/or OTA, while combinations of AFG₁, AFB₁, DON and FB₁ were found in paddy rice. Yellow noodles were contaminated with DON only; oat flakes contained DON, OTA or AFB₁, and polished rice was contaminated with AFG₁ and HT-2 toxin.     

Release of bisphenol A from polycarbonate baby bottles: water hardness as the most relevant factor

The concentrations of bisphenol A (BPA) in the content of polycarbonate baby bottles reported by scientific literature were almost always clearly below 1 μg/l, but in a German consumer journal they reached 157 μg/l. These high values were interpreted as a result of microwave heating, but here they are shown to be the result of testing with tap water. Since BPA is primarily released by degradation of the polycarbonate, rather than by migration from the polymer, testing with food simulants (distilled water or distilled water/ethanol) is not appropriate. Degassing of tap water during boiling causes the pH to increase and the water to become more aggressive. BPA concentrations may reach 50 μg/l if a polycarbonate bottle is sterilized by boiling water in it (well feasible only by means of microwave heating) and this same water is used to prepare a beverage. Increased concentrations are also observed when boiling-hot beverages with a high pH are filled into the bottle, such as boiled plain water or tea. Respecting simple rules, the BPA concentrations can be kept below 0.5 μg/l.     

Migration of polyolefin oligomeric saturated hydrocarbons (POSH) into food

POSH are polyolefin oligomeric saturated hydrocarbons, such as oligomers from polyethylene or polypropylene. POSH that have migrated into foods are easily mistaken for mineral oil-saturated hydrocarbons (MOSH). In fact, both POSH and MOSH largely consist of highly isomerised branched and possibly cyclic hydrocarbons, both forming humps of unresolved components in gas chromatography. Chromatograms are reported to show typical elution patterns of POSH and help analysts distinguishing POSH from MOSH as far as possible. Since the structures of the POSH are not fundamentally different from those of the MOSH, it would be prudent to apply the evaluation of the MOSH. However, the migration is frequently beyond that for which safety has been demonstrated. This is shown for a few examples, particularly for powdered formula for babies.     

Methods for the analysis of melamine and related compounds in foods: a review

In recent years, two adulteration incidents concerning the addition of melamine (MEL) and related compounds to dairy products and vegetable proteins have occurred in China. These episodes prompted numerous governmental and private laboratories to develop or implement methods for the analysis of a wide variety of food products for MEL and related compounds, including cyanuric acid, ammeline, and ammelide. Methods have been developed for both screening and quantitation purposes; procedures used in the methods range from sensitive hyphenated chromatographic-mass spectrometric techniques to immunoselective assays. Various issues are encountered during the analysis of MEL and related compounds in food products. These issues include contamination, matrix effects, and analyte instability, and their severity varies according to the method used, and matrices and analytes examined.     

Linear and cyclic oligomers in polybutylene terephthalate for food contact materials

Polybutylene terephthalate (PBT) is a polyester (PES) gaining more importance on the food contact material (FCM) market. However, little is known about the potential migration of PBT oligomers which are formed during polymer production. In this work, PBT pellets and a slotted spoon manufactured from this material by injection moulding were analysed on extractable oligomers and their migration potential into hydrophilic foods. Overall 27 oligomers (cycles and linears) could be identified in different extracts by HPLC-DAD/ESI-MS data, but without confirmation by reference substances. The oligomers were quantified by HPLC-DAD using bis(2-hydroxyethyl) terephthalate (BHET) as external standard and the total amount of oligomers isolated by reprecipitation from the pellets and the spoon were 0.69 and 0.71%, respectively. While cyclic oligomers made up for approximately 90% of the extractable oligomers, linear oligomers proved to be more relevant for migration into aqueous foodstuffs. Furthermore, it was shown that hydrolysis of oligomers can take place in water at elevated temperatures. Consequently, the qualitative and quantitative composition of PBT oligomers in aqueous foods from FCMs does not only depend on migration but also on hydrolysis. Migration testing of the PBT spoon under repeat use conditions with water at 100°C for 2 h resulted in 0.29 mg item^?1 of linear oligomers and 0.05 mg item^?1 of the cyclic PBT dimer in the third migrate.     

Feasibility study for the development of certified reference materials for specific migration testing. Part 1: Initial migrant concentration and specific migration

The paper describes a project with the main objective of developing the know how to produce certified reference materials (CRMs) for specific migration testing. Certification parameters discussed are the initial concentration of the migrant in the polymer (C_P,0) and the specific migration into a food simulant under certain temperature/time conditions. Sixteen preliminary candidate CRMs were defined and produced. The most important polymers (low- and high-density polyethylene (LDPE and HDPE), polypropylene (PP), polystyrene (PS), polyethylene terephtalate (PET), plasticized polyvinyl chloride (PVC), rigid PVC, polyamides (PA)) and additives as well as monomers representing different physicochemical properties as target substances for migration were chosen. The stability and homogeneity of the migrants in the materials were tested and methods for the determination of the certification parameters were developed and validated. From the 16 materials produced, the six most suitable CRM candidates (LDPE//Irganox 1076/Irgafos 168, LDPE//1,4-diphenyl-1,3-butadiene (DPBD), HDPE//Chimassorb 81/Uvitex OB, PP homo//Irganox 1076/Irgafos 168, HIPS, 1% mineral oil//styrene, PA 6//caprolactam) were selected. The feasibility of CRM production for the six candidate materials was demonstrated and a trial certification exercise was performed with participation of all four partner laboratories. All six materials showed suitable properties for future production as certified reference materials.     

Liquid chromatography-tandem mass spectrometry determination of N-nitrosamines released from rubber or elastomer teats and soothers

A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method as an alternative to a gas chromatography-thermal energy analyser (GC-TEA) method recommended by the European Committee on Standardization (CEN) was validated for the simultaneous determination of eight N-nitrosamines released into artificial saliva from rubber or elastomer teats and soothers. N-nitroso-dipropylamine-d₁₄ (NDPA-d₁₄) was used as internal standard for accurate quantification. The method was validated with relatively good analytical results, including sufficiently low limits of detection (0.1–2?µg?kg^?1 of sample) and good linearity (r ^2?>?0.99) throughout the studied concentration ranges. Intra- and inter-day precisions expressed with the relative standard deviation (RSD, %) were 3.4–8.0% and 4.4–11.3%, which were below the performance criteria based on one-half of the value derived from the Horwitz value. It was also found that the LC-MS/MS method is sufficiently rugged and successfully applicable to its routine analysis for the compliance test of Commission Directive 93/11/EEC.     

Determination of microbial transglutaminase in meat and meat products

Transglutaminase is an enzyme that can be used to cross-link pieces of meat, fish or meat products. The resulting product gives the optical impression of an intact chunk of meat. The usage of transglutaminase as a food additive is permitted in some countries. However, its utilisation has to be declared to ensure transparency for consumers. This paper describes two orthogonal analytical methods suited for the detection of technological relevant transglutaminase concentrations (around 25?mg pure enzyme in 1?kg of product) in meat and meat products. The mass spectrometry-based approach relies on a previous digestion with Achromobacter lyticus protease and LC-MS/MS separation and detection. Sufficient selectivity was obtained by monitoring four different peptides. The orthogonal (complementary and independent), ELISA-based approach relies on two commercially available bacterial transglutaminase-specific antibodies, combined to a sandwich ELISA. The two methods were tested by analysing some 60 samples obtained from the market.     

Review of the use of phytosterols as a detection tool for adulteration of olive oil with hazelnut oil

Adulteration of virgin olive oil with less expensive oils such as hazelnut oil is a serious problem for quality control of olive oil. Detection of the presence of hazelnut oil in olive oil at low percentages (<20%) is limited with current official standard methods. In this review, various classes of phytosterols in these two oils are assessed as possible markers to detect adulterated olive oil. The composition of 4-desmethyl- and 4-monomethylsterols is similar in both oils, but the 4,4′-dimethylsterols differ. Lupeol and an unknown (lupane skeleton) compound from 4,4′-dimethylsterols are exclusively present in hazelnut oil and can be used as markers via GC–MS monitoring to detect adulteration at levels as low as 2%. The phytosterol classes need to be separated and enriched by a preparative method prior to analysis by GC or GC/MS; these SPE and TLC methods are also described in this review.