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Due to the particularity of origin area, the yield and price of Tibetan chicken are different from those in the plain areas, which leads to chickens from the plains being disguised as Tibetan chickens. In present study, Tibetan chicken and chicken from other four provinces in plain areas were distinguished by stable isotopes and chemometric methods. The cross-validation rate was 97.6%. Secondly, correlation between mean δ 13 C, δ 15 N, δ 2 H and δ 18 O values in chicken samples and environmentalparameters was investigated. These indicators are closely related to geographical environment. δ 13 C and δ 15 N values were positively correlated with longitude (R = 0.955) and altitude (R = 0.796), respectively. δ 18 O and δ 2 H values were negatively correlated with latitude (R = 0.903) and altitude (R = 0.938), respectively. At last, we used stable isotopes to trace Tibetan chicken from the different area of Tibet. When four stable isotope ratios were combined, we can distinguish them., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

It has been remained a challenge to detect trace formaldehyde in complex samples, such as rice flour and duck blood products. In this study, a purge-trap device was designed and used for volatile target detection, which avoided interference adsorptions on enhanced particle surfaces during subsequent surface-enhanced Raman spectroscopy (SERS) analysis. The device produced a low detection limit for formaldehyde of 1 × 10 -4  μg/mL in the concentration ranges of 4 × 10 -3 -4 μg/mL and 1 × 10 -4 -3 × 10 -3  μg/mL. In the process of the detection of duck blood and rice flour, partial least squares regression (PLSR) was adopted for sample analysis. The formaldehyde concentration was calculated and compared to the actual value from the above model with R 2 of 0.97, which indicated high accuracy and stability. These results suggested that the proposed method was reliable and suitable for rapid analysis of trace formaldehyde in real products., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

This article presents investigation of the flavor profile on 5 different regional Chinese smoked chicken samples using gas chromatography-ion mobility spectrometry analysis methods. Five batches of samples were obtained over the course of 6 mo. A total of 34 flavor substances were identified in the 5 smoked chicken samples, including 10 aldehydes, 7 alcohols, 4 ketones, 2 hydrocarbons, 3 heterocyclic compounds, 4 esters, 2 ethers, and 2 phenolic compounds. The whole spectral fingerprint visually displayed flavor differences and relations in 5 types of smoked chicken with local characteristics. Moreover, the orthogonal projections to latent structures discriminant analysis model revealed that these samples could be separately classified into 5 groups. Multivariate statistical analysis showed that 20 chemicals with higher Variable Importance for the Projection values were the key contributors to the differences of flavor in these 5 kinds of smoked chicken. N-nonanal, heptanal, n-nonanal, heptanal, furfurol, and hexanal were the main common flavor compounds in the 5 types of Chinese smoked chicken, whereas linalool, alpha-terpineol, 1,8-cineole, and anethole were the main characteristic flavor compounds of Goubangzi chicken (No. 1); gamma-butyrolactone, 2-acetylfuran, 2-methoxyphenol, 2-acetylpyrrole, and limonene were determined as the key flavor compounds of Liaocheng chicken (No. 2); the concentration of octanal and n-nonanal was higher in Tangqiao chicken (No. 3); butyl acetate was the key contributor to the flavor compounds of Jinshan chicken (No. 4). 2-Heptanone and 2-pentylfuran had a high correlation with Zhuozishan chicken (No. 5). The different raw materials and ingredients used, especially the method of preparation and cultural differences, in different regions of the country in China were the main reasons leading to the similarities and differences of volatile compounds in the 5 kinds of Chinese traditional smoked chicken., (Copyright © 2020. Published by Elsevier Inc.)

A method was developed for the determination of four protease inhibitors (saquinavir, ritonavir, nelfinavir and indinavir) in chicken using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The samples were extracted by shaking with 30% (v/v) acetonitrile aqueous solution (containing 1% (v/v) trichloroacetic acid), and purified by using mixed-mode cationic-exchanger (MCX) cartridges. The samples were separated on a Luna ® C8 column (150 mm×2 mm, 3 μm) using 0.2% (v/v) formic acid aqueous solution (containing 5 mmol/L ammonium acetate) and acetonitrile as the mobile phases with gradient elution. The determination was carried out by using an electrospray ion source in the positive and multiple-reaction monitoring (MRM) modes. The calibration curves showed good linearities in the range of 0.1-20.0 μg/L, and the correlation coefficients ( r 2 ) were greater than 0.99. The limits of quantification (LOQs, S/N =10) of the four protease inhibitors varied from 0.20 μg/kg to 0.90 μg/kg. At the spiked levels of 1.0, 2.0, and 10.0 μg/kg, the average recoveries of the four protease inhibitors were ranging from 69.0% to 106.0%. The intra-day and inter-day relative standard deviations (RSDs) were 2.2%-13.8% ( n =6) and 3.6%-14.6% ( n =3), respectively. The method is simple, efficient, sensitive and accurate, and it can be used to detect residues of saquinavir, ritonavir, nelfinavir and indinavir in chicken.

A compilation of volatile N -nitrosamine levels in processed (e.g., cured, canned, smoked) meat and poultry products is presented. Over 1800 samples of processed meat products including bacon, ham, salami, sausage, and various other processed meat and poultry products have been examined for the presence of eight volatile N -nitrosamines. The database compiled from the literature is based on 25 references published for the period of 1985 to 2018 from 14 countries. N -nitrosodimethylamine (NDMA), N -nitrosopiperidine (NPIP), and N -nitrosopyrrolidine (NPYR), are the most frequently identified volatile N -nitrosamines occurring in processed meat and poultry products. N-nitrosodiethylamine (NDEA), and N -nitrosodibutylamine (NDBA) are also frequently observed to a lesser extent. The processed meat and poultry products with the highest levels of volatile N -nitrosamines were pork (fried, fat only eaten), poultry (fried), poultry (spiced, grilled), and bacon (fried).

The detection of adulteration and mislabeling of food products, including intensively processed meat, is a challenge which needs urgent solutions to protect consumers' rights. The aim of the study was to demonstrate the feasibility of species-specific peptide-based LC-MS methods for monitoring duck, goose and chicken in processed meat products. Food commodities of various compositions, subjected to various treatments, including homogenization, cooking, roasting, drying, and sterilization during production, were examined to ensure that MS-based methods are resistant to matrix composition changes. A qualitative LC-QQQ multiple reaction monitoring (MRM) method was developed which allows high-confidence monitoring of duck, goose and chicken meat (ten specific peptides), simultaneously with beef and pork (seven peptides), in the presence of turkey meat, in highly processed food. The developed LC-MS methods can be used for food authentication, monitoring of the food composition conformity with label statements and detection of adulteration of poultry-containing food products., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

A molecularly imprinted electrochemical sensor for toltrazuril (TZR) detection based on molecularly imprinted polymers (MIPs) immobilized on reduced graphene oxide (rGO) and titanium dioxide (TiO 2 ) modified platinum (Pt) electrode surface was fabricated for the first time. The synergistic fast electron transfer ability, large electroactive surface area and high catalytic activity from rGO and TiO 2 contribute to amplify the electrochemical signal and consequently improve the sensitivity of the sensor. The cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) tests were used to evaluate the performance of the electrochemical sensor. The results showed that the electrochemical sensor possessed high sensitivity, good selectivity and anti-interference ability toward TZR. By using the DPV, the electrochemical sensor displayed a wide linear concentration range from 0.43 to 42.54 μg/L, with a limit of detection of 0.21 μg/L (S/N = 3). Moreover, the recoveries and relative standard deviations (RSD) were 85.0%-97.0% and 3.5%-6.4% at three concentration levels, respectively, implying that the established sensor is promising for the accurate detection of TZR at trace levels in chicken muscle and egg samples., (Copyright © 2018 Elsevier B.V. All rights reserved.)

A partial substitution (25 or 50%) of dietary protein with Tenebrio molitor (TM) and Hermetia illucens (HI) meals as protein sources in the diet of Barbary partridge (Alectoris barbara) has been tested in terms of raw and cooked meat quality. Twelve partridges per feeding group (control - SBM, HI25, HI50, TM25 and TM50) were slaughtered. The peeled carcasses of the HI25, HI50, TM25 and TM50 groups were heavier than those of the SBM group, both raw and cooked. The pH, color and shear force of the raw meat were not affected to any greater extent by the diet, whereas the presence of insect meal seemed to increase the yellowness index of the cooked meat. The proximate composition was unaffected by both the species and the level of insect meal, although the fatty acid profile was changed considerably. The HI and TM groups had significantly higher C18:1n-9 and lower C16:0 contents than SBM. Furthermore, Hermetia illucens, added as 50% of the dietary protein, induced a significant increase in C12:0 and C16:1n-7. As a result, the highest AI and TI were obtained for the HI50 diet (0.38 and 0.75, respectively), whereas the TM groups both had intermediate AI values (around 0.35) and the lowest TI (0.67). Finally, the cholesterol content of the birds was not affected by insect inclusion in the feeds., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Taihe black-boned silky fowl (Gallus gallus domesticus Brisson) has a history of over 2200 years of being consumed as a curative food in China. In this work, an LC/MS-based lipidomics approach was employed to investigate the characteristic lipid composition of Taihe black-boned silky fowls from different ages and genders as well as from different carcass parts. Data were processed using an orthogonal partial least squares discriminant analysis and one-way analysis of variance. A total of 1127 lipids were detected in Taihe black-boned silky fowl muscles. Among them, 88, 11 and 1 lipid species were found to have both a variable influence on a projection value >1 and a p-value smaller than 0.05 between different age, gender and part groups. These results illustrate that the influence of the 3 investigated factors on the lipid profiles of Taihe black-boned silky fowl decreased in the order of age > gender > part. Lipid profile differences will facilitate a better understanding of the curative properties of Taihe black-boned silky fowl. Taihe and crossbred black-boned silky fowls were compared in terms of their lipid compositions based on the same strategy. The results showed that the two groups were able to discriminate from each other effectively. 47 lipid compounds were determined to be potential markers for the authentication of Taihe black-boned silky fowl. This work demonstrates the successful application of lipidomics for lipid profiling in food raw materials., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Meat quality was assessed in Cobb-500 cage vs. floor-housed broilers slaughtered at 38 vs 49 days of age. Broilers (105 birds per housing system) were reared since 1 day of age in conditions of vivarium of Center for Selection and Genetics «Zagorskoye EPH». Fat content in breast meat was significantly higher (p<0.05) at both slaughter ages in cage-housed broilers (2.0 and 2.7% at slaughter age 38 and 49 days, respectively) compared to floor-housed (1.6 and 2.2%). Protein content in breast meat was higher in floor-caged broilers. Total collagen content in thigh meat of floor housed broilers (789.88 mg/100 g) was 1.5 fold higher compared to cage-housed (515.80 mg/100 g, p<0.05). Fatty acid profiles of meat were mostly affected by the type of meat (red vs white) and to a lesser extent by housing system and slaughter age. Water-holding capacity in red meat significantly differed between slaughter ages and between housing systems at slaughter age 38 days (р<0.05): at slaughter age 38 days water-holding capacity in red meat was 67.3 in cage-housed broilers vs. 70.1% in floor-housed; at slaughter age 49 days 74.9 vs. 76.0%, respectively. The five-point scores of sensory taste evaluation for the meat of floor-housed broilers (4.55 and 4.91 for breast meat at slaughter ages 38 and 49 days; 4.40 and 4.90 for thigh meat) were better compared to cage-housed (4.47 and 4.83 for breast meat at slaughter ages 38 and 49 days; 4.37 and 4.70 for thigh meat). The conclusion was made that meat quality estimated by a set of the relevant parameters was marginally better in floor housed broilers in compare to cage-housed., Competing Interests: The authors declare no overt and potential conflict of interest related to the publication of this article., (Copyright© GEOTAR-Media Publishing Group.)

Heterocyclic amines (HAs) are considered as potential mutagens and carcinogens, and are found in trace quantities (ng/g level) in food samples. Therefore, it is important to develop a selective and effective method to determine trace HAs in complex matrices. In this study, acrylamide-modified graphene (AMG) was successfully synthesised and showed good stability and permeability in aqueous and organic phases. AMG was used as an efficient adsorbent in the online micro-solid-phase extraction (μ-SPE) of trace HAs. The enrichment factors of the AMG μ-SPE column were determined as 78-166 for six HAs. An online method based on AMG μ-SPE coupled to high-performance liquid chromatography was developed. The limits of detection ranged from 0.70 to 2.5 ng/L. Trace HAs in spicy salted duck, baked fish, and fried chicken samples were determined and the concentrations of 2-amino-3-methylimidazo[4,5-f]quinoine, 2-amino-3,4-dimethylimidazo[4,5-f]quinoine, and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline in these samples were 4.7-37.3, 8.1-15.4, and 43.3-109 ng/g, respectively. The recoveries for the six HAs ranged from 65.9% to 118%, and the relative standard deviation (RSDs) were less than 10.8%. The proposed online method was sensitive, reliable, and convenient for the analysis of trace HAs in food samples., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Two sensitive and selective spectrofluorimetric methods are proposed to determine ethopabate (ETH) and amprolium hydrochloride (AMP). First derivative synchronous spectrofluorimetry determines the natively fluorescent ethopabate at 288 nm in presence of amprolium hydrochloride which is a non fluorescent quaternary compound with average recovery 100.54±0.721 over a concentration range of 0.01-0.8 μg/mL. Limits of detection (LOD) and quantification (LOQ) are 0.002 and 0.007 μg/mL, respectively. The second method is direct synchronous spectrofluorimetry for determining amprolium hydrochloride at 362 nm after a reaction with 5% NaOH and 0.08% potassium ferricyanide that is optimized by a two-level factorial design. This method is linear over a concentration range of 0.01-0.65 μg/mL with average recovery 99.4±1.28. Limits of detection (LOD) and quantification (LOQ) are 0.002 and 0.006 μg/mL, respectively. The proposed methods are found to be valid and applicable for the analysis of ETH and AMP in their veterinary formulation. They are successfully applied to determine the studied drugs in chicken plasma and their residues in chicken muscle, liver, egg and chicken-based baby food product with recoveries in the ranges of 95.71-108.73% and 97.36-111.89% and for ETH and AMP, respectively., (Copyright © 2015 Elsevier B.V. All rights reserved.)

The preparation and consumption of bone broth is being increasingly recommended to patients, for example as part of the gut and psychology syndrome (GAPS) diet for autism, attention-deficit hyperactivity disorder, dyslexia, dyspraxia, depression and schizophrenia, and as part of the paleolithic diet. However, bones are known to sequester the heavy metal lead, contamination with which is widespread throughout the modern environment. Such sequestered lead can then be mobilised from the bones. We therefore hypothesised that bone broth might carry a risk of being contaminated with lead. A small, blinded, controlled study of lead concentrations in three different types of organic chicken broth showed that such broths do indeed contain several times the lead concentration of the water with which the broth is made. In particular, broth made from skin and cartilage taken off the bone once the chicken had been cooked with the bones in situ, and chicken-bone broth, were both found to have markedly high lead concentrations, of 9.5 and 7.01 μg L(-1), respectively (compared with a control value for tap water treated in the same way of 0.89 μg L(-1)). In view of the dangers of lead consumption to the human body, we recommend that doctors and nutritionists take the risk of lead contamination into consideration when advising patients about bone broth diets., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

The aim of this study was to develop an optical biosensor inhibition immunoassay, based on the surface plasmon resonance (SPR) principle, for use as a screening test for 13 (fluoro)quinolones, including flumequine, used as veterinary drugs in food-producing animals. For this, we immobilised various quinolone derivatives on the sensor chip and tested binding of a range of different antibodies (polyclonal and one engineered antibody) in the presence and absence of free (fluoro)quinolones. The main challenge was to detect flumequine in an assay giving good results for the other compounds. One antigen-antibody combination proved satisfactory: polyclonal antibodies raised against a dual immunogen and, on the sensor chip, a fluoroquinolone derivative. It was the first time that this concept of the bi-active antibody was described in the literature. The assay, optimised for detection in three matrices (poultry muscle, fish, and egg), was tested on incurred samples prepared by liquid extraction followed by two washing steps. This rapid, simple method proved adequate for detecting at least 13 (fluoro)quinolones at concentrations below established maximum residue levels (MRLs). The reference molecule norfloxacin could be detected in the range of 0.1-10 microg kg(-1) in extracts of egg and poultry meat and in the range of 0.1-100 microg kg(-1) in extracts of fish. The determined midpoints of these calibration curves were about 1, 1.5 and 3 microg kg(-1) in poultry meat, egg and fish, respectively.

One of the most convenient methods for the identification of animal species in processed meat products is the examination of DNA sequences. Real-time polymerase chain reaction (qPCR) techniques are particularly suitable because even small fragments of DNA formed during heat processing of the meat can be amplified and identified. A real-time PCR method has been developed and evaluated for the identification of processed meat products. In test mixtures containing beef, pork, horse, mutton, chicken and turkey, it was possible to identify these species down to a level of 0.05%. By adjusting the number of cycles, it was possible to detect levels as low as 0.01% of these species. Cross-reactivity between these species was not found, except for pure horsemeat (250 ng DNA) in the assay for turkey meat. Cross-reactivity of deer, roe, ostrich, kangaroo, goat, domestic duck, mallard, goose, pigeon, guinea fowl, quail and pheasant was also investigated and it was found that amounts as high as 250 ng DNA of these species in the reaction vial did not result in (false) positive signals except for amounts higher than 125 ng deer DNA and higher than 50 ng pigeon DNA in the determination of chicken and beef, respectively. More than 150 meat samples were examined using DNA hybridization and real-time PCR. A comparison of the results showed a better performance of the real-time procedure compared to DNA hybridization.

Between 1997 and 1999, several cases of dioxin contaminations in foodstuffs of animal origin occurred in Europe due to feed contaminated by several independent sources: citrus pulp pellets, fat containing polychlorinated biphenyls (PCB), and kaolinitic clay as anti-caking agent in feedingstuffs. As a consequence of the latter, a survey on polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) in food of animal origin was initiated by the Swiss authorities to assess the extent of PCDD/F contamination and to document the efficiency of the measures taken to ensure the decontamination of the food supply. Investigation of a total of 128 samples of cow's milk, poultry, eggs, and meat revealed several cases of residue levels distinctly above the background exposure limit of approximately 2.5 ng of I-TEQ/kg (fat basis). Particularly, elevated concentrations were found in eggs (maximum 13 ng of I-TEQ/kg), poultry (maximum 3.9 ng of I-TEQ/kg), and pork (maximum 7.5 ng of I-TEQ/kg). On the basis of the observed PCDD/F congener pattern, the contamination could be attributed to PCDD/F-contaminated kaolin that was used as an anti-caking agent in particular feedstuffs.

The 2-alkylcyclobutanone method was adopted as a European Standard (EN1785) and MAFF Validated Method (MAFF V37) in 1996 for the detection of irradiated food containing fat. As the method requires a relatively long period (ca 2 days) of time for extraction of the 2-alkylcyclobutanones from a foodstuff, a means was sought to increase the speed at which these irradiation markers could be isolated while at the same time decreasing the amount of organic solvents required. Thus, the technique of supercritical fluid extraction (SFE) was investigated. Results showed that SFE can be used for the rapid extraction (60 min) of lipid from irradiated foods such as chicken, pork, liquid whole egg, ground beef, and from the seeds of irradiated mango and papaya with only 10 mL n-hexane being necessary for collection of the extracted sample. A method was also developed whereby the 2-alkylcyclobutanones can be selectively extracted from irradiated foods without prior extraction of the lipid. The sample extract, in 10 mL n-hexane, is purified through a Florisil SPE cartridge which is washed with 10 mL n-hexane and the 2-alkylcyclobutanones eluted with 10 mL 2% diethyl ether in n-hexane before analysis by gas chromatography/mass spectrometry. 2-Dodecylcyclobutanone and 2-tetradecylcyclobutanone were selectively extracted from irradiated chicken meat, liquid whole egg, ground beef, and mango as well as from beef burgers and baked products containing irradiated ground beef and liquid whole egg, respectively. Using this method, samples can be analyzed for irradiation treatment within 6 h as opposed to the 2-day period required for the EN1785/MAFF V37 validated method.

Near-infrared reflectance spectroscopy (NIRS) calibrations were developed to enable the accurate and fast prediction of the total contents of methionine, cystine, lysine, threonine, tryptophan, and other essential amino acids, protein, and moisture in the most important protein-rich feed ingredients. More than 1000 samples of global origin collected over four years were analyzed on amino acids following the official methods of the United States and the European Union. Detailed data and graphics are given to characterize the obtained calibration equations. NIRS was validated with independent samples for soy and meat meal products and compared to the amino acid predictions using linear crude protein regressions. With a few exceptions, validation showed that 85-98% of the amino acid variance in the samples could be explained using NIRS. NIRS predictions compared to reference results agree excellently, with relative mean deviations below 5%. Especially for meat and poultry meals, NIRS can predict amino acids much better than crude protein regressions. By enabling the amino acid analysis of many samples to be completed in a short time, NIRS can improve the accuracy of feed formulation and thus the quality and production costs of mixed feeds.

Arachidonic acid (AA) is an extremely important fatty acid involved in cell regulation. When provided in the diet, it is cogently incorporated in membrane phospholipids and enhances eicosanoid biosynthesis in vivo and in vitro; however, controversy exists as to the levels of AA in food and in the diet. This study determined the amount of AA in cooked and raw portions of beef (rib eye), chicken (breast and thigh), eggs, pork (loin), turkey (breast), and tuna; it compared these results to values published in Agriculture Handbook No. 8 (HB-8). The cooked portions were prepared as described in HB-8. With the exception of chicken thigh and tuna, the levels of AA (w/w) in the selected foods analyzed were significantly higher, in general, than those values published in HB-8. The greatest differences were observed in beef (raw and cooked), turkey breast (raw and cooked), and pork (cooked) where AA levels were twice that of the values in HB-8. In contrast, the AA and n-3 fatty acid contents in tuna were almost half the HB-8 values. The present data indicate that HB-8 tends to underreport the amounts of AA in a number of foods commonly consumed in the American diet, and new initiatives should be considered to validate and update the current database for fatty acid composition of foods.

Research was conducted to develop a more accurate and less time-consuming method of determining expressible moisture in poultry meat. Two modifications of wrapping meat in netting (fold wrap or basket wrap) were compared to a conventional method that did not include wrapping meat. Ground, dark poultry meat, with and without 2.0% added NaCl, was wrapped in netting and analyzed for expressible moisture. The fold wrap method was determined to be more accurate and easier to use, as less expressed meat adhered to the surrounding filter papers. Thus, actual expressed moisture absorbed by filter papers was measured.

The mutagenic activities of the alkaline fractions derived from various heat-processed, ready-made meat, fish and poultry foods were studied using the Salmonella mutagenicity assay with strain TA98 and S-9 mix to provide information about the mutagenicity of everyday Finnish foods. The majority of the food samples tested were mutagenic. The mutagenic activities of various commercial ready-made products. Mutagenicity varied remarkably between different samples. The cooking temperature clearly affected the mutagenicities of fried or reheated food samples, mutagenicity increasing with increasing temperature. The results indicate that the main sources of cooked-food mutagens in everyday Finnish foods are grilled and broiled products and foods fried at restaurants and at home. By comparison, commercial ready-made fried foods are only a minor source of mutagenicity. Variations between equivalent food samples indicated that heat processing has a marked effect on the mutagenic activity of the product, which might therefore be reduced by modifying the cooking process.

Four composite diets from three cities, each representing the daily per capita consumption of foods in Canada, contained on analysis 191, 220, 113, and 150 mug selenium. Cereals provided the most selenium (62-112 mug) followed by meat, poultry, and fish (25-90 mug) and dairy products (5-25 mug). The average daily intake of selenium in Canada was also calculated from published analytical data and the per capita disappearance of unprepared foods. The total intake was 197 mug/day, and the major sources were wheat flour (98 mug), pork (21 mug), poultry products (24 mug), and fish (17 mug). Because the average diet is rich in selenium, the possibility of a deficiency in the adult is considered to be remote. Milk is relatively low in selenium, and thus the greatest deprivation in humans would occur during infancy.

Since 1964 the Food and Drug Administration Total Diet study has reported residues of pesticides and other chemicals ingested in the diet of a young adult male, statisically the Nation's largest eater. During the tenth year of the study, pesticide residues remained at the relatively low levels previously reported. Thirty market baskets were collected in 30 cites which ranged in population from less than 50,000 to 1,000,000 or more. Averages and ranges of residues are reported from August 1973 through July 1974 by food class. Individual items in the dairy and meat composites in four market baskets were analyzed for pesticides; results are included. Data for lead, cadmium, selenium, mercury, arsenic, and zinc are also included. Results of recovery studies within various classes of residues are also presented.

A critical and exhaustive review of published and unpublished data on the zinc content of foods showed that, with few exceptions, the major dietary sources of zinc were foods of animal origin. Oysters, which contained more than 5 mg. zinc per 3-oz. cooked portion, were an outstanding source of zinc. Lean beef and beef liver were also among the foods highest in zinc and ground beef was a good source. Dark meat of poultry contained more zinc than light meat, and turkey was higher in zinc than chicken. Egg yolk, but not egg white, was relatively high in zinc, as were nonfat dry milk and Cheddar cheese. Foods of plant origin, like those of animal origin, varied widely in zinc content. Cocoa and the milling fractions of bran and germ of wheat were high in zinc. Seeds of plants, such as muture dry legumes and peanuts, were better sources of zinc than were leaves, stalks, fruits, or roots. Vegetables, fruits, oils, fats, tea, coffee, and carbonated beverages contained little zinc. Factors influencing the zinc content of foods were evaluated. Provisional tables, giving representative values for zinc in more than two hundred foods, both in 100-gm. portions and in common household units, based on this research, are presented.

A method is described for the determination of polycyclic aromatic hydrocarbons (PAHs) with 3-7 rings in (I) meat, poultry, fish, and yeast; and (II) oils and fats. The extraction of PAHs from group I is incomplete, and, therefore, group I samples must be dissolved homogeneously by saponification in 2N methanolic potassium hydroxide. The PAHs are concentrated by liquid-liquid extraction (methanol-water-cyclohexane, N,N - dimethylformamide - water-cyclohexane) and by column chromatography on Sephadex LH 20. The PAHs are separated by high-performance gas-liquid chromatography (GLC) with columns containing 5% OV-101 on Gas-Chrom Q and estimated by integration of the flame ionization detector signals in relation to an internal standard (3,6-dimethylphenanthrene and/or benzo(b)chrysene). The sensitivity is significantly higher than that obtained with ultraviolet spectroscopic methods. The reproducibility and margin of error were tested with meat samples fortified with 11 PAHs and with samples of sunflower oil. The method was further applied to meat, smoked fish, yeast, and unrefined sunflower oil. All samples investigated contained more than 100 PAHs (characterized by mass spectrometry) of which only the main components were determined: phenanthrene, anthracene, fluorene, fluoranthene, pyrene, benzo(a)anthracene, chrysene, benzo(b)fluoranthene + benzo (j)fluoranthene + benzo(k) fluoranthene, benzo(e)pyrene, benzo(a)pyrene, perylene, dibenz(a,j)anthracene, dibenz(a,h)anthracene + indeno(1,2,3,-cd)pyrene, benzo(ghi)perylene, anthanthrene, and coronene. In contrast to other methods, the GLC profile analysis allows the recording of known and unknown PAH peaks simultaneously and also allows a compilation of all PAHs.

During the ninth year of the Total Diet Study, pesticide residues remained at the relatively low levels reported previously. Thirty market baskets were collected in 30 cities which ranged in population from less than 50,000 to 1,000,000 or more. Averages and ranges of residues found are reported for the period August 1972 through July 1973 by food class. Lead, selenium, and zinc data are included for the first time. During this period, the individual items used in making up the dairy and meat composites in four market baskets were analyzed for pesticides and the results are included. Results of recovery studies within various classes of residues are also presented.

Six types of salted fish and 10 other sorts of salted food products traditionally consumed by southern Chinese were analysed by GC-MS for the presence of volatile nitrosamines. The detection limit in the original raw food was 1 microg/kg for each nitrosamine. Only NDMA, in the range of 1-35 microg/kg, could be detected, in four of the six types of salted fish samples examined; and no nitrosamines were found in the other salted food products.

Representative values for folacin in 299 foods have been developed, based on an extensive literature review. A provisional table of these folacin values has been prepared for foods in 100-gm. portions and for specified weights, representing common household units. The data reflect newer methodology than that used for a prior USDA publication, namely, protection of folacin by ascorbic acid. L. casei is the preferred assay organism. The table includes values for both free and total folacin; however, the authors recommend that, in calculating routine hospital diets, total rather than free folacin be used; this would allow easy and direct comparison with the Recommended Dietary Allowances.

The mercury contents in samples of flour, sugar, nonfat dry milk, potatoes, hamburger, chicken breast, shrimp, liver, eggs, and whole milk were determined by neutron activation analysis. The mercury was separated by anion exchange chromatography and precipitated as the sulfide. The mercury concentrations for all these foods were below 50 parts per billion.