Trans fatty acids in the Portuguese food market

Consistent evidence exist on the harmful health effects of industrial trans fatty acids (TFA). In order to have accurate data on TFA intake and implement adequate measures to reduce their intake, each country should have updated estimates of TFA content in the diet. The objective of the present study was to provide data on the TFA content in food commercialized in the Portuguese market. The results on the TFA content of 268 samples acquired between October and December 2013 are reported. Samples were categorized as margarines and shortenings (n = 16), spreadable chocolate fats (n = 6), fried potatoes and chips (n = 25), industrial bakery (n = 4), breakfast cereals (n = 3), pastry products (n = 120), seasonings (n = 5), instant soups (n = 5), instant desserts (n = 6), chocolate snacks (n = 4), microwave popcorn (n = 4), cookies, biscuits and wafers (n = 53), and fast-food (n = 13), with butter (n = 4) included for comparison purposes. TFA were quantified by gas chromatography. Total TFA content in the fat ranged from 0.06% to 30.2% (average 1.9%), with the highest average values in the “biscuits, wafers and cookies” group (3.4% TFA), followed by the pastry group (2.0%). Fifty samples (19%) had TFA superior to 2% in the fat. These findings highlight there is still much need for improvement in terms of the TFA content in Portuguese foods, particularly in traditional pastry.     

Assessment of trans fatty acids in edible oils in China

Trans fatty acid (TFA) is commonly present in edible oils. TFA has been proven to have adverse effects on blood lipids, including increasing the LDL-cholesterol concentration and decreasing the HDL-cholesterol concentration. The aim of our study was to determine the levels of TFA in edible oil samples consumed in Harbin, China. In this study, 93 samples of soybean oil (SBO) (n = 29), rapeseed oil (RSO) (n = 23), sunflower oil (SFO) (n = 22), and corn oil (CO) (n = 19) were analyzed between October 2010 and January 2011, using a gas chromatograph (GC) with a flame ionization detector (FID). TFA (>2%) was detected in 17 (18%) samples, ranging from 0.14% to 4.76%. The overall TFA content was 1.15 ± 0.12% for SBO, 1.37 ± 0.23% for RSO, 1.41 ± 0.10% for SFO, and 2.01 ± 0.24% for CO. Trans C18:2 and C18:3 fatty acids were normally predominant in the investigated edible oils. The variance in the percentage of TFA in the edible oils probably resulted from differences in the quality, processing technique, and storage condition of the edible oils. The results indicated that, in China, TFA is widely present in edible oils at low levels. Therefore, it is important to assess the content of TFA in edible oils in China.     

Fast screening method for the analysis of trans fatty acids in processed food by CZE-UV with direct detection

In the present work, an alternative method for trans fatty acids (TFA) analysis with direct UV detection using capillary zone electrophoresis (CZE-UV) is proposed. The background electrolyte used consisted of 12.0 mmol L⁻¹ of tetraborate buffer, 12.0 mmol L⁻¹ of Brij 35, 33% methanol and 17% acetonitrile. Trans fatty acids in different samples such as butter toffee, cake mix, stuffed wafers, chocolate and a mix for Brazilian cheese bread were successfully quantified within an analysis time of 13 min, taking into account the statistical approach based on response factor calculation using C19:1 (nonadecaenoic acid) as internal standard. The statistical comparison between CZE-UV and the classical GC method for the analyzed samples did not present significant differences within the 95% confidence interval.     

Species determination of pine nuts in commercial samples causing pine nut syndrome

Consumption of pine nuts from the species of Pinus armandii has been reported to cause dysgeusia, commonly known as pine mouth, or pine nut syndrome (PNS). However, the number of reports on pine nut consumptions of the different species and PNS is limited. This leaves open the possibility that other pine species than P. armandii could be involved in PNS as well. This study investigated 18 samples involved in PNS and received at the Danish Veterinary and Food Administration in 2011 through 2012. Samples were subjected to gas chromatographic analysis of fatty acids. The content of 11 individual fatty acids was used together with the diagnostic index and the sum of Δ5-fatty acids as diagnostic parameters. Diagnostic parameters from samples were then compared to reference material and literature data to determine the species. In a limited number of samples, the diagnostic parameters matched neither our reference materials nor literature data. However, the morphology, the fatty acid analysis, and externally obtained DNA sequencing data suggest a P. armandii subspecies or a variety. With these possible P. armandii subspecies, P. armandii was identified in all analyzed samples. The application of principal component analysis (PCA) to the data set showed a satisfactory separation of the majority of the 13 pine species included in the study.     

Effects of gamma irradiation on trans fatty acid composition in ground beef

The present study was conducted to evaluate the combined effects of irradiation (0, 1, 3, 5 and 7 kGy) of ground beef on fatty and trans fatty acids. Irradiation of ground beef was performed by gamma rays from a ⁶⁰Co source. Irradiated ground beef samples had higher concentrations of total trans fatty acids than the control samples. Irradiated ground beef samples with 7 kGy had the highest total trans fatty acids, total monounsaturated and total unsaturated fatty acids than the other samples. In this study results showed an increase in trans fatty acids related to the increase on irradiation dose in ground beef and irradiation dose changed fatty acids composition especially trans fatty acids in ground beef.     

Limited survey of deoxynivalenol in wheat from different crop rotation fields in Yangtze-Huaihe river basin region of China

The food toxin, deoxynivalenol (DON) is frequently present in cereals such as wheat, barley and maize, which are infected by Fusarium asiaticum and Fusarium graminearium. Crop rotation and climatic conditions play a major role in the Fusarium infection in wheat. In this present study, a minor survey was conducted to find out the impact of crop rotation affecting the Fusarium infection leading to DON contamination in wheat samples from selected infected regions of Jiang su and An hui provinces, China, especially during harvest period in 2012. A total of 84 wheat samples from the highly Fusarium infected region were collected, of which 30, 8, 39 and 7 samples were from the fields where cotton, corn, rice, and soya bean was a rotation crop, respectively. DON concentration in wheat sample was analyzed by high performance liquid chromatography (HPLC) combined with ultraviolet detection. DON contamination in the wheat samples was 95% with the mean DON concentration of 3881.2 μg/kg from both the regions. Average DON contamination in wheat samples from cotton, soya beans, corn, and rice rotation fields were 2067.5, 2853.6, 3517.5, and 4899.3 μg/kg, respectively. Nearly 34% of the wheat samples from the cotton rotation fields were below the DON maximum tolerable limits of EU (1750.0 μg/kg) and only 3% samples were above 4000.0 μg/kg DON concentration. However, the average DON contamination level was the highest in wheat samples (4899.3 μg/kg) where rice was a rotation crop, with 64% of the samples were above 4000.0 μg/kg. The present study shows cotton could be a promising rotation crop in the regions where wheat is more prone to the infection of Fusarium sp, which may minimize the economic loss to the farmers in wheat.     

Quality assessment of Scomber colias japonicus under modified atmosphere and vacuum packaging

The effect of initial head-spaces of atmospheric air, vacuum and modified atmospheres packaging (50% CO₂/50% N₂) on microbiological, physicochemical and sensory changes of chub mackerel (Scomber colias japonicus) was studied at 3 and 6 °C. The microbial flora of chub mackerel comprised mainly lactic acid bacteria, Brochothrix thermosphacta (Gram-positive flora) and secondly pseudomonads, Shewanella putrefaciens, Enterobacteriaceae (Gram-negative bacteria). The spoilage of chub mackerel stored under modified atmosphere was delayed compared with those samples stored under vacuum or air. The concentrations of moisture, ash, protein, fat and polyunsaturated fatty acids were not affected during the storage period compared to the pH values and the concentrations of lactate and ammonia that showed significant differences.     

A rapid method for monitoring total trans fatty acids (TTFA) during industrial manufacturing of Brazilian spreadable processed cheese by capillary zone electrophoresis

An alternative method for monitoring total trans fatty acids (TTFA) in hydrogenated vegetable fat (HVF) and spreadable processed cheese (SPC) using capillary zone electrophoresis (CZE) and indirect UV detection is proposed. This method is a simple, efficient and rapid way to monitor both raw materials and the final SPC product. The importance of printing nutritional tables on product labels, to provide more accurate information to consumers, and incorporation of stricter quality controls during food processing is emphasised. Following calculation of the response factor (R_f), the CE method was applied to TTFA analysis in SPC samples, and compared with the accepted AOCS gas chromatography (GC) method. According to a paired sample t test, no significant difference was found between the CE and GC methods within the 95% confidence interval for five different brands analysed in genuine duplicate (p-value > 0.05). The optimised CE method was applied to analyse the TTFA content of the hydrogenated vegetable fat raw material and the SPC final product. Based on our results, this optimised CE method can be successfully used for routine analysis of TTFA in SPC samples with a run time of 7.5 min.     

Mycotoxin contamination in corn smut (Ustilago maydis) galls in the field and in the commercial food products

Corn infected with Ustilago maydis, causal agent of common smut disease, produces galls that are used as food in certain cultures, but may be contaminated with mycotoxins. The objective of this study was to determine mycotoxin levels in common smut galls (CSGs) collected from the field at corn ear reproductive stages R1 through R5 and in commercial CSGs products. The study was conducted in 2012 and 2013. A simple extraction method for five mycotoxins was devised and the results showed the presence of these compounds in CSGs in corn during ear development at various physiological stages. Fumonisin was the major mycotoxin in CSG samples in both 2012 (63%, ≤150.7 μg g⁻¹) and 2013 (46.9%, ≤20.9 μg g⁻¹); followed by aflatoxin (2012: 2%, ≤14.7 ng g⁻¹; 2013: 30.6%, ≤10.8 ng g⁻¹) and zearalenone (2012: ≤41.70 ng g⁻¹; 2013: ≤12.40 ng g⁻¹). Deoxynivalenol (DON) was only detected in 2012 (≤1.6 μg g⁻¹), and cyclopiazonic acid was only detected in 2013 (≤3.18 μg g⁻¹). Commercial canned and fresh CSG samples also contained detectable amounts of mycotoxins including aflatoxin, fumonisin, CPA, and DON. Aspergillus flavus was isolated from selected 2013 CSG field samples at R2 or older (0–1.6 × 10⁶ cfu/g), whereas Fusarium spp were isolated at R1 or older (0–7.5 × 10⁷ cfu/g). These results indicate that CSGs can be infected with mycotoxigenic fungi and contaminated with mycotoxins. The incidence of mycotoxins in commercially available CSG products was highly variable and warrants further study.     

Histamine production by Raoultella ornithinolytica in canned tuna meat at various storage temperatures

Canned tuna meat was inoculated with Raoultella ornithinolytica at a level of 2.0 log CFU/g (low) or 5.0 log CFU/g (high) and stored at 4, 15, 25, or 37 °C to investigate bacterial growth and formation of total volatile base nitrogen (TVBN) and histamine in canned tuna meat. R. ornithinolytica grew rapidly in all samples stored at temperature above 15 °C regardless of the inoculation levels. The histamine contents quickly increased to higher than 50 mg/100 g within 12 h in the low inoculated samples and stored at 37 °C as well as in those inoculated with the high level and stored at 25 °C or higher. However, growth of R. ornithinolytica and its histamine production were inhibited when samples were stored at 4 °C. The TVBN contents in all samples were all below 30 mg/100 g during storage even when the levels of histamine in some samples increased to greater than 50 mg/100 g. Therefore, canned tuna meat was a good substrate for histamine formation by bacterial histidine decarboxylation at elevated temperatures (> 15 °C) when it is contaminated with R. ornithinolytica.     

A minor survey of deoxynivalenol in Fusarium infected wheat from Yangtze–Huaihe river basin region in China

Deoxynivalenol (DON) is frequently present in infected cereals such as wheat, barley and maize. Fusarium asiaticum and Fusarium graminearium are the key fungal species which produces DON, when they infect wheat in China. Our present study is to do a minor survey on the presence of DON in the highly infected wheat regions from Jiang su and An hui province, China, harvested during the year 2010. A total of 56 wheat samples which are naturally infected by Fusarium sp., of which 35 samples from Jiang su province and 21 samples from An hui province were taken up for the study. The samples were analyzed for the presence of DON by using high performance liquid chromatography (HPLC) combined with ultraviolet detection. The recoveries of DON from the spiked samples (500–15,000 μg/kg) were obtained in the range of 85.7–90.2%, with the average relative standard deviation of 2.7%. The average percentage of contamination in all the samples was 89.3%, with the DON concentration ranging between 259 and 4975 μg/kg, and with the mean of 1962 μg/kg. According to the Chinese standard limits for DON, nearly 70% of the samples were above the maximum tolerable level of 1000 μg/kg. However, only 44% of the samples exceeded the European commission limits for unprocessed wheat of 1750 μg/kg. Regions where there was higher level of Fusarium sp. contamination due to climatic changes like heavy rainfall with high humidity, showed the presence of higher levels of DON in the samples. Cropping of Fusarium resistant wheat cultivars like Sumai 3 in the regions where the wheat is highly susceptible for the Fusarium contamination could help in the reduction of contamination in wheat.     

Effects of oil types and pH on carcinogenic polycyclic aromatic hydrocarbons (PAHs) in grilled chicken

The effects of oil types and the pH of marinade were investigated on the formation of carcinogenic polycyclic aromatic hydrocarbons (EPA priority 16 PAHs) in grilled chicken. The formation of PAHs in grilled chicken breast with different marinades after charcoal-grilling for 3 min/side was evaluated using high performance liquid chromatography with a photodiode array detector (HPLC-DAD). Compared with the control marinade treatment (without vegetable oil), the addition of commercial palm oil and sunflower oil that contained significantly different amounts of polyunsaturated and saturated fatty acids led to a significant (p < 0.05) increase in the PAH levels in grilled chicken from 190.1 μg/kg to 457.6 μg/kg and 376.6 μg/kg, respectively and there was only a slight difference between both oil marinade treatments due to the presence of antioxidant compounds in the commercial vegetable oils. The pH values of the marinade treatments for both acidic and alkali marinades using citric acid and sodium bicarbonate, respectively, produced the highest pH value (7.51, alkali marinade) which resulted in a major increase of more than 70% in the PAH levels in grilled chicken. The results of this study suggested that the addition of oil and/or alkali ingredients in the marinade could be important in increasing the levels of PAHs in grilled meat products.     

Mineral and fatty acid profile of high intensity pulsed electric fields or thermally treated fruit juice-milk beverages stored under refrigeration

The influence of High Intensity Pulsed Electric Fields (HIPEF) or Thermal Treatment (TT) on minerals and fatty acids of fruit juice-whole (FJ-WM) or skimmed milk (FJ-SM) beverages was assessed after processing and during chilled storage. Mineral profile of both beverages was characterized by Ca, Zn, Fe, Mg, Cu, and Mn; being Ca the macroelement detected at the highest concentration (3.06–3.17mg/100 mL). Neither HIPEF nor TT significantly affected mineral concentration of the beverages, except Fe, which augmented after HIPEF (300%) or TT (43%). During storage (56 days), mineral content in both bevearges remained highly stable, regardless of the treatment applied. 11 fatty acids were identified in untreated and processed FJ-WM beverages. Palmitic acid was detected at highest concentration (21.83–24.37 mg/100 g of fat). Immediately after HIPEF or TT, most fatty acids remained with no significant changes, only linoleic acid increased (20%) in HIPEF treated beverage. Fatty acid content of HIPEF treated FJ-WM beverages was kept constant along storage; only palmitic, linoleic and linolenic acids showed lower concentrations (12–20%) at day 56. Conversely, the concentration of most fatty acids in the heated beverage underwent a significant reduction (7–19%) with time, except palmitic acid, which remained constant. HIPEF can be considered as a potential alternative to conventional pasteurization to obtain stable mixed beverages with significant concentrations of health-related compounds.     

Natural occurrence of aflatoxin B1, ochratoxin A and citrinin in Croatian fermented meat products

When domestic animals are exposed to mycotoxins, significant amounts of the latter shall be carried over into animal products such as milk, eggs and meat. This study was carried out in order to determine the possible presence of aflatoxin B₁ (AFB₁), ochratoxin A (OTA) and citrinin (CIT) in game sausages (n = 15), semi-dry sausages (n = 25) and fermented dry-meat products (n = 50), randomly taken from individual producers and the Croatian market. AFB₁ and OTA were quantified using ELISA, while CIT was quantified using HPLC-fluorescence detector. Out of 90 samples, the fungi most frequently isolated from dry-cured meat products were of Penicillium species, while Aspergillus was isolated from only one sample. As much as 68.88% of the samples were positive for mycotoxins. Finally, the analysis of different types of meat products resulted in OTA identification in 64.44%, CIT identification in 4.44% and AFB₁ identification in 10% of the samples. The maximum OTA concentrations established in the commercial sausage samples equalled to 7.83 μg/kg, while that of AFB₁ amounted to 3.0 μg/kg. Generally, although OTA was detected in all three types of products in different percentage shares, mutual differences were not statistically significant (P > 0.05).     

Fat removal with hydrolyzed corn starch for real-time qPCR detection of Salmonella enterica in ground beef in 4.5 hours without enrichment

The rapid detection of low number of Salmonella in ground beef ideally requires an effective and economic molecular assay. The molecular analysis for the detection of Salmonella in ground beef by the polymerase chain reaction requires efficient methodology for extraction of targeted cells and effective removal of PCR inhibitors from the sample. The efficacy of hydrolyzed corn starch for the removal of fat along with the use of activated charcoal coated with milk proteins to remove PCR inhibitors were assessed. Salmonella enterica ser. Enteritidis was detected by real-time quantitative PCR at a level of 1 CFU/g of ground beef in 25 g samples containing 7%, 15% or 27% fat without enrichment. This study documents that partially hydrolyzed corn starch functions as effectively as beta-cyclodextrin for selective removal of fat.     

Histamine content and histamine-forming bacteria in mahi-mahi (Coryphaena hippurus) fillets and dried products

Forty-two mahi-mahi fillets and 17 dried products sold in retail markets in Taiwan were tested for histamine and histamine-forming bacteria. The levels of pH, salt content, water content, Aw, TVBN, APC, TC and Escherichia coli in mahi-mahi fillet samples ranged from 5.6 to 6.5, 0.05 to 2.44%, 70.9 to 82.8%, 0.95 to 0.99, 5.9 to 23.5 mg/100 g, 3.1 to 7.0 log CFU/g, <3 to 1650 MPN/g and <3 to 45 MPN/g, respectively. The levels of pH, salt content, water content, Aw, TVBN, APC, TC and E. coli in dried mahi-mahi samples ranged from 5.7 to 6.4, 0.63 to 20.13%, 7.1 to 42.9%, 0.51 to 0.85, 21.4 to 133.9 mg/100 g, 3.6 to 8.7 log CFU/g, <3 to 5900 MPN/g and <3 to 2500 MPN/g, respectively. The average content of various biogenic amines in fillets samples was less than 0.3 mg/100 g. Four of the 17 dried samples (23.4%) had histamine levels greater than the FDA guideline of 5 mg/100 g for scombroid fish and/or product with one of them containing 68.15 mg/100 g of histamine, which is greater than the 50 mg/100 g hazard action level. Eight histamine-producing bacterial isolates, capable of producing 12.6 ppm–562 ppm of histamine in trypticase soy broth supplemented with 1.0% l-histidine (TSBH), were identified as Raoultella ornithinolytica (three isolates), Pantoea agglomerans (two isolates), Proteus vulgaris (two isolates) and Enterobacter amnigenus (one isolate), by 16S rDNA sequencing with PCR amplification.     

Degradation in soybean oil,sunflower oil and partially hydrogenated fats after food frying,monitored by conventional and unconventional methods

This paper aims to study discontinuous deep frying of potatoes, milanesas (breaded bovine Semimembranosus muscle) and churros (flour, water, milk, lemon and salt) in soybean oil, sunflower oil and partially hydrogenated fats, monitored by conventional and unconventional methods. With the exception of partially hydrogenated fat after 80.5 h of deep-frying churros, all the oils exceeded 25% of total polar compounds (TPC) and the content of polymeric and dimerized triacylglycerols were higher than 10%, prevailing thermal alterations. For none of the samples the percentage of free fatty acids exceeded 2% of oleic acid. The losses of tocopherols during frying reached 76.0%. Little significant alterations occurred in the fatty acids composition, iodine index calculated, saponification index and formation of trans isomers after frying. The rapid tests used to determine TPC, malondialdehyde and alkenals have proved to be viable alternatives to monitor the quality of frying oils.     

Evaluation of carbonyl species in fish oil: An improved LC–MS/MS method

Fish oil, a common source of omega-3 fatty acids, can be easily oxidized to generate carbonyl species, thus, the measurement of these compounds in fish oil are significant for food safety. Here, a comprehensive and sensitive method to quantify forty-four carbonyl species including toxic substances such as acrolein, glyoxal, methylglyoxal and trans-4-hydroxy-2-hexenal in fish oil has been developed and validated. The samples were derivatized with 2,4-dinitrophenylhydrazine, cleaned using C18 solid phase extraction, and analyzed by liquid chromatography coupled with tandem mass spectrometry. The calibration curves represented satisfactory linearity (r² > 0.998) and the quality control samples showed favorable precisions within an acceptable range (RSD < 10%). The accuracies ranged from 96 to 109%. The detection and quantification limits ranged from 1.5 to 30 ng/mL and 5–90 ng/mL, respectively. The method was successfully applied to determine carbonyl species in ten fish oil products. The proposed method is suitable for high throughput analysis of carbonyl species in fish oil.     

Prevalence of foodborne pathogens in Turkish Van otlu (Herb) cheese

The survey was conducted on 50 unripened Van otlu cheese samples obtained in Van and Hakkari markets at retail level to determine the microbial characteristics with special emphasis on Staphylococcus aureus, Escherichia coli, E. coli O157:H7 and Salmonella spp. The results revealed that S. aureus and E. coli were present in extremely high numbers, with a mean 6.10 and 3.68 log CFU/g, respectively. S. aureus was found in all samples ranging from 2.48 to 7.15 log CFU/g and was present in more than 5.0 × 10⁵ CFU/g in 54% of the samples whereas E. coli was found in 62% of the samples. None of the samples contained E. coli O157:H7; but 3 of the 50 samples had Salmonella spp. The results indicate that Van otlu cheese presents a potential hazard for public health; and the necessary precaution will have to be taken to improve the sanitary practices and cheese manufacturing technique.     

Influence of partial replacement of NaCl with KCl,CaCl2 and MgCl2 on proteolysis,lipolysis and sensory properties during the manufacture of dry-cured lacón

The influence of three salting treatments (treatment II: 50% NaCl–50% KCl; treatment III: 45% NaCl, 25% KCl, 20% CaCl₂ and 10% MgCl₂ and treatment IV: 30% NaCl, 50% KCl, 15% CaCl₂ and 5% MgCl₂) on the proteolysis and lipolysis through the dry-ripening process was evaluated and compared to those of control lacón (treatment I: 100% NaCl). Lacón elaborated with treatment III had a delayed oxidation in relation to control. Statistical analysis showed significant (P < 0.05) differences on total free amino acids and total free fatty acids among treatments at the end of process. Differences in some free amino acids and free fatty acids, generated along the processing, were detected among treatments and at the end of dry-curing. Data suggests a slight trend towards a major proteolysis during treatment III and a major lipolysis during treatment IV. Finally, sensory analysis noticed significant differences in the saltiness and bitterness attributes between the control batch and the other ones.