Vitamin (B1, B2, B3 and B6) content and oxidative stability of Gastrocnemius muscle from dry-cured hams elaborated with different nitrifying salt contents and by two ageing times.

The effect of the amount of added nitrate and nitrate plus nitrite to dry-cured hams on the vitamin (B1, B2, B3, B6) content, the antioxidant enzyme superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSHPx) activities and the thiobarbituric acid reactive substances (TBARS) was assessed in Gastrocnemius muscle at the end of two ripening processes. Five different curing mixtures (Hi-N: 600 KNO3; Lo-N: 150 KNO3; Hi-Mix: 600 KNO3+600 NaNO2; Lo-Mix: 150 KNO3+150 NaNO2; Hi-Mix/Asc: 600 KNO3+600 NaNO2+500 sodium ascorbate, expressed as mg of salts added on surface per kg of fresh ham) were evaluated in dry-cured hams aged for 11.5months (standard process, SP) and 22months (long process, LP). Minor differences in target parameters between the hams due to the process were found. The amount of nitrate when it was added alone or as a mixture of nitrate and nitrite, as well as the ascorbate addition to dry-cured hams did not affect vitamin B1, B2 and B3 contents. The level of vitamin B6 was affected by both the amount and the mixture of salts; the addition of nitrite reduced around 40% the content of vitamin B6, but it was not affected by nitrate or ascorbate. The activity of SOD and CAT decreased with the amount of nitrate and nitrite, while GSHPx and TBARS resulted unaffected.

Effect of pH(24h), curing salts and muscle types on the oxidative stability, free amino acids profile and vitamin B2, B3 and B6 content of dry-cured ham.

The effects of a curing salt composition (with and without nitrifying salts), and the pH at 24h postmortem (pH24>6.0, 5.5

Analysis of vitamin B1 in dry-cured sausages by hydrophilic interaction liquid chromatography (HILIC) and diode array detection.

A method based on hydrophilic interaction liquid chromatography (HILIC) and diode array detection (DAD) was developed to quantify thiamine (vitamin B1) concentration in Spanish dry-cured sausages ("chorizo," "fuet," and "salchichón"). Samples were extracted with diluted acid (HCl 0.1M) followed by an enzymatic hydrolysis to release vitamin B1 vitamers from food matrix. Crude extracts were purified on a weak cation exchange SPE cartridge and total thiamine concentration was determined by LC-HILIC-DAD with a limit of detection better than 0.01 mg/100g. The proposed conditions, that do not require the derivatization of the extracts nor the use of fluorescence or MS detectors, are suitable to provide chromatographic separation and identification of vitamin B1 within 8 min. Selectivity, repeatability and accuracy of the method were evaluated with both spiked samples and the reference material Pig Liver BCR® 487. Quantification of vitamin B1 was also carried out for different kinds of commercial samples of Spanish dry-cured products.

Analysis of seven purines and pyrimidines in pork meat products by ultra high performance liquid chromatography-tandem mass spectrometry.

An ultra high performance liquid chromatography-tandem mass spectrometry method (UPLC-MS/MS) is proposed for the simultaneous quantification of inosine, adenosine, guanosine, uridine, hypoxanthine, xanthine and uric acid in pork meat, dry-cured and cooked ham. Samples were added with (15)N(2)-xanthine (internal standard) and extracted with boiling water for 30 min. Supernatants were washed with hexane, added with formic acid 10% in water, methanol:acetone (1:1, v/v), evaporated to dryness under N(2), and finally re-dissolved in water prior to injection. Chromatographic separation was carried out with a HSS T3 column with a total time of analysis of 15 min. Two specific transitions for each compound were used for identification and quantification (with matrix matched calibration curves). Linearity, limit of detection, repeatability and accuracy were evaluated. The method was used to quantify the seven purines and pyrimidines in 15 commercial samples.

Detection of tetracycline and oxytetracycline residues in pig and calf hair by ultra-high-performance liquid chromatography tandem mass spectrometry.

An ultra-high-performance liquid chromatography tandem mass spectrometry method to detect residues of tetracycline (TC), epi-tetracycline (eTC) and oxytetracycline (OTC) in animal hair was developed. Hair samples were washed with water, extracted with NH(4)OH 0.1M, purified by SPE-C(18) cartridge and analyzed by tandem mass spectrometry (ESI(+), MRM mode) with satisfactory results. For the first time, accumulation of TC, eTC and OTC was confirmed in livestock hairs after a therapeutic treatment with TC and OTC, respectively. Administered drug residues were detectable in hair samples up to 2 months after the last treatment, providing a retrospective evidence of TC and OTC administration. Hair analysis seems to offer a wider window of detection than edible tissues.

Effects of tetracycline administration on the proteomic profile of pig muscle samples (L. dorsi).

Effect of tetracycline (TC) administration on the proteomic profile of pig muscle was evaluated by 2D electrophoresis and MALDI-TOF mass spectrometry. The TC content at slaughter was determined in L. dorsi samples by HPLC-DAD. Mean residual concentration of TC in the muscle of treated animals, calculated as the sum of TC and epi-TC was 126.3 microg/kg, indicating a rapid elimination of TC in this tissue. Several differential spots (n = 54, p < 0.05) were observed in protein profiles from control and treated animals. MALDI-TOF identification gave a positive match for 5 differential spots, that is, glycerol-3-phosphate dehydrogenase 1 (G3PD1), phosphoglycerate kinase 1, novelprotein (0610037L13Rik), leucine aminopeptidase 3 (LAP), and hypothetical protein isoform 2. Results show that proteomics could be a useful tool to reveal pharmacological treatments with TC, even if the possible uses of differential spots as biomarkers to detect illegal administration of TC require further studies. Different spot patterns as a consequence of TC treatments seem to be another interesting issue for the consequences on tissue metabolism and meat quality.

Determination of changes in protein conformation caused by pH and temperature.

Protein denaturation has a major impact on meat quality parameters such as water holding capacity, tenderness and color. Specific information about structural changes of the individual muscle proteins post-mortem could help understand the factors affecting meat quality. An aromatic dye, 4,4'-dianilino-1,1'-binaphthyl-5,5'-disulfonic acid (bisANS) that binds to the hydrophobic patches of proteins was used to monitor changes in the conformation of individual sarcoplasmic proteins caused by pH. The bisANS reagent was covalently linked to the proteins with UV-light and the proteins were separated and identified using gel electrophoresis and mass spectrometry. The results showed that the sarcoplasmic proteins creatine kinase M, aldolase A and lactate dehydrogenase showed increased hydrophobicity whereas carbonic anhydrase III showed decreased hydrophobicity with increasing pH. Temperature only had a marked effect on the results at around 40°C, there being no change between 25 and 35°C.

Novel approach to control sulfamethazine misuse in food-producing animals by hair analysis.

The presence of sulfamethazine residues in pig and calf hair was compared with the residual levels encountered in the corresponding edible tissues (liver and muscle) as a consequence of drug administration. Sulfamethazine up to 84.7 mg kg-1 was found in calf hair samples after a pharmacological treatment, with a significant effect of hair pigmentation. High concentrations of the parent drug were detected in calf hair for 4 weeks after administration, when sulfamethazine residues were no longer detectable in the corresponding edible tissues. In a similar way, pig hair also accumulated sulfamethazine residues up to 40.5 mg kg-1, which was more than the amount detected in the corresponding muscle and liver samples at slaughter. Hair analysis seems a suitable tool to improve the efficacy of regulatory controls, and thus the safety of the food chain and to discourage the improper use of sulfamethazine in animal farming.

A simplified LC-DAD method with an RP-C12 column for routine monitoring of three sulfonamides in edible calf and pig tissue.

Use of an RP-C(12) analytical column with a mobile phase at pH 4.5 enabled excellent chromatographic separation and quantification of sulfadiazine (SDZ), sulfamerazine (SMR), and sulfamethazine (SMZ) in edible calf and pig tissue (muscle and liver). Tissue samples were extracted with acetonitrile, centrifuged without further clean-up, and analyzed by LC-DAD. The proposed conditions are useful for a rapid and reliable screening of the SDZ, SMR, and SMZ content of calf and pig tissue at concentrations lower than the maximum residue level (MRL) (LOQ between 27 and 55 ppb). Separation of some possible SMZ metabolites should be further investigated.

Hair analysis for veterinary drug monitoring in livestock production.

This review summarizes the basic information and applications concerning the use of hair analysis for the detection of misuse of therapeutic and anabolic agents in livestock animals. Hair biology, hair-shaft structure and the mechanisms of drug incorporation are described, considering the different factors which can affect the deposition. Sampling and extraction methods are reviewed with special attention to the particularities of this matrix, while the use of different analytical techniques is discussed, taking into account the concentration and the sensitivity required for drug detection. Advantages, drawbacks, promising prospects and possible applications of this technique in the future are also discussed.

Detection of sulphamethazine residues in cattle and pig hair by HPLC-DAD.

An HPLC method with diode array detection (DAD) is proposed for the detection of sulphamethazine (SMZ) residues in pig and cattle hair. Hair samples were extracted under alkaline conditions (NH4OH 0.2M for calf samples and NaOH 0.1M for piglet samples) and purified with a dual solid-phase extraction (SPE) cartridge system (reverse phase/strong-cation exchange). Recovery of SMZ in fortified samples varied from 70 to 85%, with a limit of quantification of 0.155 ng/mg. Residues of SMZ (7.2-59.2 ng/mg) were detected both in calf and piglet hairs after a therapeutic treatment with SMZ, while no interfering peak was observed in samples from untreated animals.