A Study on Mineral Oil Hydrocarbons (MOH) Contamination in Pig Diets and Its Transfer to Back Fat and Loin Tissues.

This study assessed saturated mineral oil hydrocarbons (MOSH) and aromatic mineral oil hydrocarbons (MOAH) levels in grower-finisher feeds for pigs supplemented with 5% crude palm oil (CP), crude olive pomace oil (COP), olive pomace acid oil (OPA), or a blend of CP and OPA (50:50, w/w); the contribution of the lipid source to that contamination; and the ability of pigs to accumulate MOH in back fat and loin tissues after 60 days of trial. MOSH and MOAH were analyzed with liquid chromatography (LC)-gas chromatography (GC)-flame ionization detection (FID) after sample preparation. Among the lipid sources, CP had the lowest MOH levels, but CP feeds showed the highest contamination. This, along with the different MOSH profiles, indicated the presence of more significant contamination sources in the feeds than the lipid source. The higher MOH contamination in CP feeds was reflected in the highest MOSH levels in pig back fat, whereas MOAH were not detected in animal tissues. Also, MOSH bioaccumulation in pig tissues was influenced by the carbon chain length. In conclusion, feed manufacturing processes can determine the MOSH contamination present in animal adipose tissues that can be included in human diets.

Endogenous n-Alkanes in Vegetable Oils: Validation of a Rapid Offline SPE-GC-FID Method, Comparison with Online LC-GC-FID and Potential for Olive Oil Quality Control.

The potential of endogenous n-alkane profiling for the assessment of extra virgin olive oils (EVOO) adulteration (blends with cheaper vegetable oils) has been studied by relatively few authors. Analytical methods used for this purpose often involve tedious and solvent-intensive sample preparation prior to analytical determination, making them unattractive. A rapid and solvent-sparing offline solid phase extraction (SPE) gas chromatography (GC) flame ionization detection (FID) method for the determination of endogenous n-alkanes in vegetable oils was, therefore, optimized and validated. The optimized method demonstrated good performance characteristics in terms of linearity (R2 > 0.999), recovery (on average 94%), and repeatability (residual standard deviation, RSD < 11.9%). The results were comparable to those obtained with online high-performance liquid chromatography (HPLC)-GC- FID ( RSD < 5.1%). As an example of an application to prove the potentiality of endogenous n-alkanes in revealing frauds, the data set obtained from 16 EVOO, 9 avocado oils (AVO), and 13 sunflower oils (SFO), purchased from the market, was subjected to statistical analysis and principal component analysis. Two powerful indices, namely (n-C29 + n-C31)/(n-C25 + n-C26) and n-C29/n-C25, were found to reveal the addition of 2% SFO in EVOO and 5% AVO in EVOO, respectively. Further studies are needed to confirm the validity of these promising indices.

A study on the impact of harvesting operations on the mineral oil contamination of olive oils.

During the 2020-21 olive oil campaign, the contribution of harvesting operations to mineral oil saturated (MOSH) and aromatic hydrocarbon (MOAH) contamination was studied. Oils extracted from hand-picked olives (15 different olive groves) generally had background MOSH (<2.7 mg/kg), and no quantifiable MOAH. In 40% of the cases, an important contamination increase was observed after harvesting operations. Except for one sample (325.8 and 111.0 mg/kg of MOSH and MOAH, respectively), other samples reached 4.3-33.7 mg/kg of MOSH and 1.1-11.3 mg/kg of MOAH. Accidental leaks of lubricants and/or contact with lubricated mechanical parts, were identified as important sources of contamination. Chromatographic traces obtained by on-line high-performance liquid chromatography (HPLC)-gas chromatography (GC)-flame ionization detection (FID) allowed for source identification. A comprehensive two-dimensional gas chromatographic platform (GC × GC) with parallel FID/MS detection was implemented for confirmation and to attempt the characterization of the contaminations. Good harvesting practices are suggested to minimize contamination risks.

Quantification and characterization of mineral oil in fish feed by liquid chromatography-gas chromatography-flame ionization detector and liquid chromatography-comprehensive multidimensional gas chromatography-time-of-flight mass spectrometer/flame ionization detector.

Mineral oil is an ubiquitous food contaminant potentially toxic. It is generally divided into aromatic hydrocarbons (MOAH) and saturated hydrocarbons (MOSH). These compounds are currently under investigation by the European Union to determine their occurrence and their toxicity before legislating on the matter. Although the discussion mainly focuses on food, animal feed can indirectly contribute to human exposure to such a contaminant. In this study, seven commercial feeds were analyzed. The analyses were carried out in two different Universities (Udine-IT and Liège-BE), performing the same sample preparation protocol: microwave-assisted saponification and extraction followed by epoxidation for the MOAH fraction. The final determination was performed by hyphenated liquid-gas chromatography (LC-GC) and LC coupled to comprehensive multidimensional gas chromatography (LC-GC × GC) with parallel detection, namely flame ionization detector (FID) and time-of-flight mass spectrometer (ToFMS). The results obtained by the two laboratories were generally in good agreement. The results obtained by LC-GC × GC-ToFMS/FID platform provided consistent results, with the advantages of more robust data interpretation that can compensate for problems occurring during purification. Moreover, the coupling of enhanced separation obtained by GC × GC and the MS information allowed for a more in-depth characterization of the contamination.

Optimization and validation of microwave assisted saponification (MAS) followed by epoxidation for high-sensitivity determination of mineral oil aromatic hydrocarbons (MOAH) in extra virgin olive oil.

A rapid and solvent-saving method, based on microwave-assisted saponification (MAS) followed by epoxidation and on-line liquid chromatography (LC) - gas chromatography (GC) - flame ionization detection (FID), was optimized and validated for high-sensitivity MOAH determination in extra virgin olive oils. Quantitative recoveries and good repeatability were obtained even at concentrations of added mineral oils close to the LOQ (0.5 mg/kg for the total hump, 0.2 mg/kg for each single C-fraction). The validated method, also applied for MOSH determination (C-fraction LOQ: 0.5 mg/kg), was used to analyse 18 extra virgin olive oils from the Italian market or oil mills, and 10 additional samples extracted in the laboratory (with an Abencor apparatus) from hand-picked olives. The former resulted contaminated with variable amounts of MOSH and MOAH (on average 19.0 mg/kg and 2.5 mg/kg, respectively), while the latter showed no detectable MOAH, and low and rather constant MOSH (generally below 2.0 mg/kg).

A Review on the Occurrence and Analytical Determination of PAHs in Olive Oils.

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental and processing contaminants, which may contaminate vegetable oils due to atmospheric fall-out or bad production practices. Due to their carcinogenic and toxic effects, surveillance schemes and mitigation strategies are needed to monitor human exposure to PAHs. In particular, due to the lipophilic nature of these substances, edible oils may present unsafe levels of these compounds. Among these, olive oil, and in particular extra virgin olive oil, is a high-value commodity, also known for its health benefits. Therefore, the occurrence of contaminants in this product is not only of health concern but also causes economic and image damage. In this review, an overview of the occurrence of PAHs in all categories of olive oil is provided, as well as a description of the official methods available and the analytical developments in the last 10 years.

On-Line HP(LC)-GC-FID Determination of Hydrocarbon Contaminants in Fresh and Packaged Fish and Fish Products.

BACKGROUND: Fish products can be contaminated with mineral oil hydrocarbons (MOH), mainly as a result of environmental contamination (wild fish) or contaminated feeds (farmed fish). Packaged products may also be contaminated with polyolefin oligomeric hydrocarbons (POH), which, depending on the packaging, storage condition, matrix composition, and fat content, may migrate relatively easily from the packaging to the food. OBJECTIVE: A rapid, solvent-sparing method for determining hydrocarbon contaminants in fish products was developed, validated, and applied to farmed and wild fish products (both fresh and packaged samples, stored under different conditions). METHOD: Microwave-assisted saponification (MAS) was used in combination with on-line LC-GC-flame ionization detection (FID). RESULTS: The proposed method showed quantitative recovery, good repeatability, and high sensitivity. Farmed salmon had variable mineral oil saturated hydrocarbon contamination (from 0.5 to 4.3 mg/kg), accompanied by mineral oil aromatic hydrocarbons (maximum 1.4 mg/kg), while wild salmons had no detectable contamination. Samples of one farmed salmon and a swordfish, both sliced and packed under vacuum, resulted contaminated with POH migrated from the packaging. POH migration was also evident in a ready-to-eat meal. CONCLUSIONS: The proposed method showed good performance characteristics in terms of recovery, repeatability, and LOQ. Fatty fish products are more prone to contamination with hydrocarbon contaminants. HIGHLIGHTS: MAS allows for rapid and efficient sample preparation. An LC-GC-FID method for MOH/POH determination in fish products was validated. Fish products may be contaminated with variable amounts of hydrocarbon contaminants.

Occurrence of n-Alkanes in Vegetable Oils and Their Analytical Determination.

Vegetable oils contain endogenous linear hydrocarbons, namely n-alkanes, ranging from n-C21 to n-C35, with odd chain lengths prevalent. Different vegetable oils, as well as oils of the same type, but of different variety and provenience, show typical n-alkane patterns, which could be used as a fingerprint to characterize them. In the first part of this review, data on the occurrence of n-alkanes in different vegetable oils (total and predominant n-alkanes) are given, with a focus on obtaining information regarding variety and geographical origin. The second part aims to provide the state of the art on available analytical methods for their determination. In particular, a detailed description of the sample preparation protocols and analytical determination is reported, pointing out the main drawbacks of traditional sample preparation and possible solutions to implement the analysis with the aim to shift toward rapid and solvent-sparing methods.

Molecularly Imprinted Polymer as Selective Sorbent for the Extraction of Zearalenone in Edible Vegetable Oils.

A method based on the selective extraction of zearalenone (ZON) from edible vegetable oils using molecularly imprinted polymer (MIP) has been developed and validated. Ultra-high-pressure liquid chromatography coupled with a fluorescence detection system was employed for the detection of zearalenone. The method was applied to the analysis of zearalenone in maize oil samples spiked at four concentration levels within the maximum permitted amount specified by the European Commission Regulation (EC) No. 1126/2007. As a result, the proposed methodology provided high recoveries (>72%) with good linearity (R2 > 0.999) in the range of 10-2000 µg/kg and a repeatability relative standard deviation below 1.8%. These findings meet the analytical performance criteria specified by the European Commission Regulation No. 401/2006 and reveal that the proposed methodology can be successfully applied for monitoring zearalenone at trace levels in different edible vegetable oils. A comparison of MIP behavior with the ones of QuEChERS and liquid-liquid extraction was also performed, showing higher extraction rates and precision of MIP. Finally, the evolution of ZON contamination during the maize oil refining process was also investigated, demonstrating how the process is unable to completely remove (60%) ZON from oil samples.

Migration of Polypropylene Oligomers into Ready-to-Eat Vegetable Soups.

Polyolefin oligomeric hydrocarbons (POH) are non-intentionally added substances (NIAS) which mainly reside in the polymer (PE, PP) as a consequence of the polymerization process, and that under favorable conditions (high fat content, high temperature, and long contact time) may migrate at high amount from the packaging into the food. The food industry offers a wide range of ready-to-eat products, among these, vegetable soups designed to be stored at refrigeration temperature (for times around 6 weeks), and in most cases to be heated for a few minutes in a microwave oven (into the original container, mostly of PP) before consumption. The present work aimed to study for the first-time migration of POH during the shelf life of these products, including storage at refrigeration temperature and after microwave heating. On-line high-performance liquid chromatography (HPLC)-gas chromatography (GC), followed by flame ionization detection (FID), was applied for POH analysis in a number of ready-to-eat products purchased from the Italian market. Microwave heating determined a variable POH increase ranging from 0.1 to 6.2 mg/kg. Parameters possibly affecting migration such as fat content and heating time were also studied.

Microwave-Based Technique for Fast and Reliable Extraction of Organic Contaminants from Food, with a Special Focus on Hydrocarbon Contaminants.

Due to food complexity and the low amount at which contaminants are usually present in food, their analytical determination can be particularly challenging. Conventional sample preparation methods making use of large solvent volumes and involving intensive sample manipulation can lead to sample contamination or losses of analytes. To overcome the disadvantages of conventional sample preparation, many researchers put their efforts toward the development of rapid and environmental-friendly methods, minimizing solvent consumption. In this context, microwave-assisted-extraction (MAE) has obtained, over the last years, increasing attention from analytical chemists and it has been successfully utilized for the extraction of various contaminants from different foods. In the first part of this review, an updated overview of the microwave-based extraction technique used for rapid and efficient extraction of organic contaminants from food is given. The principle of the technique, a description of available instrumentation, optimization of parameters affecting the extraction yield, as well as integrated techniques for further purification/enrichment prior to the analytical determination, are illustrated. In the second part of the review, the latest applications concerning the use of microwave energy for the determination of hydrocarbon contaminants-namely polycyclic aromatic hydrocarbons (PAHs) and mineral oil hydrocarbons (MOH)-are reported and critically overviewed and future trends are delineated.

Solid-phase microextraction with gas chromatography and mass spectrometry determination of benzo(a)pyrene in microcrystalline waxes used as food additives.

Microcrystalline waxes are mixtures of solid, saturated hydrocarbons mainly branched and characterized by a carbon number over C60. They are used as food additives for the surface treatment of confectionery and some fruit varieties, in chewing gum base, protective coatings, defoaming agents, and surface finishing agents. Commission Regulation No 231/2012 established physical and chemical specifications for microcrystalline waxes to use in food, and posed a limit of 50 µg/kg for benzo(a)pyrene. Due to the low solubility of microcrystalline waxes in organic solvents and matrix interferences, analytical determination of benzo(a)pyrene represents a difficult task. The official method for indirect determination of total polycyclic aromatic hydrocarbons uses unspecific spectrophotometric detection and a quite laborious, time- and solvent-consuming extraction method. A liquid-liquid partition method followed by solid-phase microextraction was developed to isolate benzo(a)pyrene from the bulk of saturated hydrocarbons in microcrystalline waxes, with the aim to have a simple and effective method to verify compliance with the legal limit. The final determination was carried out by gas chromatography coupled to mass spectrometry. Good linearity was obtained, along with a recovery of about 80% from the liquid-liquid partitions. The repeatability of the entire method was <6% and accuracy was <3%.