The assessment of carcass composition of Awassi male lambs by real-time ultrasound at two different live weights

The accuracy of ultrasonography to measure fat thickness (FT) and longissimus dorsi muscle (LM) traits (area, depth and width) in live Awassi male lambs and predict carcass FT and LM traits was studied.Twenty six Awassi male lambs were randomly divided into light (L) (n = 13) and heavy (H) (n = 13) finishing lambs. Slaughter weight of lambs in L and H groups were 40 and 45 kg, respectively. FT and LM traits, cross-sectional area between the 12th and 13th rib were measured using real-time ultrasound in vivo and on the carcass after slaughter. All ultrasound and carcass measurements were the same except live weight (LW) (P < 0.001), cold carcass weight (CCW) (P < 0.001) and carcass LM width (P < 0.05). Overall, correlation coefficients between ultrasound and carcass FT, LM depth, width and area were 0.79, 0.82 (P < 0.001); 0.60, 0.58 (P < 0.05); 0.48, −0.17 (P > 0.05) and 0.89, 0.87 (P < 0.001), respectively, for lambs in L and H groups. The introduction of ultrasound FT and ultrasound LM area as independent variables in addition to LW in the multiple regression equations further improved the variations for carcass FT (84%, 71%), carcass LM area (79%, 79%), CCW (72%, 65%) for lambs in light and heavy groups whereas no improvement was observed for carcass yield.These results indicate that in vivo ultrasound FT and measurement of the LM area in association with LW could be used to estimate carcass FT, carcass LM area and CCW in different LW Awassi lambs.     

Detection of the frequency, antimicrobial susceptibility, and genotypic discrimination of Aeromonas strains isolated from municipally treated tap water samples by cultivation and AP-PCR

The frequency, antibiotic susceptibility, and genotypic discrimination of Aeromonas strains isolated from municipally treated drinking tap water distribution systems were investigated in this study. We have analyzed 148 tap water samples collected from 8 different locations by bacterial cultivation and arbitrarily primed polymerase chain reaction (AP-PCR). Gram negative, hemolytic, oxidase (+) and catalase (+) bacterial colonies were applied to the study. Identification of bacterial colonies was done by conventional biochemical method and API ID 20E panel (BioMerieux-France). Molecular epidemiological discrimination of the isolates was done by AP-PCR. Aeromonas spp. was detected in 6 of 148 (4%) tap water samples from 8 different locations. Five isolates were identified as Aeromonas hydrophila and one isolate was identified as Vibrio fluvialis by conventional biochemical method. These data were also confirmed by API 20E panel. One of 6 isolates was resistant to gentamicin, 2 of 6 isolates were resistant to trimethoprim/sulfamethoxazole, 4 of 6 isolates were resistant to ampicillin and ampicillin-sulbactam and all of 6 isolates were resistant to cephalothin. All isolates were found to be susceptible to amikacin, aztreonam, ceftazidime, ceftriaxone, ciprofloxacin. All 6 strains of Aeromonas were discriminated by AP-PCR and were determined that all isolates were from different genotypic sources. Although the frequency of the isolates was under the standard limits, the results indicate that hemolytic A. hydrophila are present in municipally treated tap water samples in Mersin City. While all strains were genotypically distinct, all of them were resistant to first generation beta lactam antibiotics tested in this study.     

Strategies to prevent mycotoxin contamination of food and animal feed: a review

Mycotoxins are fungal secondary metabolites that have been associated with severe toxic effects to vertebrates produced by many important phytopathogenic and food spoilage fungi including Aspergillus, Penicillium, Fusarium, and Alternaria species. The contamination of foods and animal feeds with mycotoxins is a worldwide problem. We reviewed various control strategies to prevent the growth of mycotoxigenic fungi as well as to inhibit mycotoxin biosynthesis including pre-harvest (resistance varieties, field management and the use of biological and chemical agents), harvest management, and post-harvest (improving of drying and storage conditions, the use of natural and chemical agents, and irradiation) applications. While much work in this area has been performed on the most economically important mycotoxins, aflatoxin B(1) and ochratoxin A much less information is available on other mycotoxins such as trichothecenes, fumonisin B(1), zearalenone, citrinin, and patulin. In addition, physical, chemical, and biological detoxification methods used to prevent exposure to the toxic and carcinogenic effect of mycotoxins are discussed. Finally, dietary strategies, which are one of the most recent approaches to counteract the mycotoxin problem with special emphasis on in vivo and in vitro efficacy of several of binding agents (activated carbons, hydrated sodium calcium aluminosilicate, bentonite, zeolites, and lactic acid bacteria) have also been reviewed.     

Effect of vanillin, ethyl vanillin, and vanillic acid on the growth and heat resistance of Cronobacter species

Preservatives could be part of an effective intervention strategy for the control of Cronobacter species in foods, but few compounds with the desired antimicrobial properties have been identified to date. We examined the antibacterial activity of vanillin, ethyl vanillin, and vanillic acid against seven Cronobacter spp. in quarter-strength tryptic soy broth with 5 g/liter yeast extract (TSBYE) adjusted to pH 5.0, 6.0, and 7.0 at 10, 21, and 37°C. All compounds exhibited pH- and temperature-dependant bacteriostatic and bactericidal activity. MICs of vanillin and ethyl vanillin consistently increased with decreasing pH and temperature, but vanillic acid had little activity at pH values of 6.0 and 7.0. The MICs for all temperatures, pH values, and bacterial strains tested were 2 mg/ml ethyl vanillin, 3 mg/ml vanillin, and >8 mg/ml vanillic acid. MBCs also were influenced by pH, although significantly higher concentrations were needed to inactivate the bacteria at 21°C than at 10 or 37°C. Survivor curves for Cronobacter sakazakii strains at the MBCs of each compound revealed that all treatments resulted in immediate loss of cell viability at 37°C. Measurements of propidium iodide uptake indicated that the cell membranes were damaged by exposure to all three compounds. The thermal resistance of C. sakazakii was examined at 58°C in TSBYE supplemented with MBCs of each compound at pH 5.0 and 6.0. D-values at pH 5.0 were reduced from 14.56 ± 0.60 min to 0.93 ± 0.01, 0.63 ± 0.01, and 0.98 ± 0.02 min for vanillin, ethyl vanillin, and vanillic acid, respectively. These results suggest that vanillin, ethyl vanillin, and vanillic acid may be useful for the control of Cronobacter spp. in food during preparation and storage.     

The effects of rosemary extract combination with vacuum packing on the quality changes of Atlantic mackerel fish burgers

The effects of the use of antioxidant technology on the quality of mackerel burgers stored at 4 °C were investigated in terms of sensory, biochemical [thiobarbituric acid (TBA), total volatile basic nitrogen (TVB‐N), peroxide value (PV) and free fatty acids (FFA)] and microbiological analyses [total viable count (TVC)]. Fish meat was divided into three groups; the control (C) without rosemary extract, the second group with 0.4% rosemary extracts (Group A) and the third with 0.8% rosemary extracts (Group B). Results showed that the TVB‐N level did not exceed acceptability limit (30–35 mg 100 g^?1) for all groups. TBA value for the control significantly increased from 1.47 to 4.80 MA kg^?1 whereas it slightly increased in treatment groups as the storage time increased. Significantly higher PV and FFA (P < 0.05) were obtained from the control group. Rosemary extract, in combination with vacuum pack was effective in controlling the growth of bacteria and biochemical indices.     

Fast and simple extraction of pesticide residues in selected fruits and vegetables using tetrafluoroethane and toluene followed by ultrahigh-performance liquid chromatography/tandem mass spectrometry

An extraction and analytical method for the determination of pesticide residues in fruits and vegetables has been developed. The method includes extraction with a pressurised liquid solvent containing a mixture of 1,1,1,2-tetrafluoroethane and toluene, and identification/quantification of pesticides using ultrahigh-performance liquid chromatography coupled to tandem mass spectrometry (UPLC/MS/MS). Validation studies were carried out to evaluate the performance of the method for the determination of 71 different pesticides and metabolites in tomato, cucumber, pepper, spinach, zucchini, grape, cherry, peach and apricot. Matrix-matched calibration curves were applied and correlation coefficients (r(2)) came out to be greater than 0.99. Limit of quantification (LOQ) values of the active substances were found to be lower than the maximum residue limits (MRL) according to regulations in Turkey. The recovery values were found to be between 70% and 120% with relative standard deviations less than 20%. Based on these results, the proposed method is fast, cheaper, rugged and gives quantitative results with no additional clean-up steps.     

A Kinetic Study on the Heat-Induced Changes of Whey Proteins Concentrate at Two pH Values

Whey protein concentrate (WPC) is used as food ingredients due to their commercially important functional properties. The effects of heat treatment on the components of milk are very important for the final product character, since they undergo modifications that affect sensorial and nutritional quality of milk. The heat-induced changes on dispersions of whey proteins concentrate were monitored by measurement of thiol availability, protein solubility, and turbidity at pH 6.6 and 7.5. The fractional conversion model was used to quantitatively describe the effect of different temperature–time combination on denaturation mechanism. The results demonstrate that heat-induced changes of WPC greatly influence their solubility, expressed as degree of denaturation at pH 4.6 and were related to the heating conditions. The denaturation mechanism involved a number of consecutive conformational changes in the molecules. A curvature in Arrhenius plots was observed around 75 °C, indicating changes in the reaction mechanism. The deflection of Arrhenius plot reflects the generally accepted two-step denaturation/aggregation process of whey proteins.     

Combination of freeze drying and molecular inclusion techniques improves the bioaccessibility of microencapsulated anthocyanins from black rice (Oryza sativa L.) and lavender (Lavandula angustifolia L.) essential oils in a model food system

Black rice and lavender are promising sources of bioactives, in terms of anthocyanins and essential oils. Their bioaccessibility were improved by microencapsulation, followed by mixing in order to benefit both from colour and flavour, along with radical scavenging and biological properties. The mixed powder showed a satisfactory anthocyanins of 2.55 mg g⁻¹ DW, leading to a radical scavenging activity of 65.14 mmol g⁻¹ DW. The powder displayed an inhibitory effect against α-glucosidase (~49%) and α-amylase (39%), respectively, with a controlled release in intestinal environment. To further examine the functional properties, the powder was added to a food model system. During storage, a release in anthocyanins and flavonoids were found, leading to an increase in radical scavenging activity. The sensorial analysis showed that supplemented biscuits were appreciated for colour and lavender aroma. The obtained results were promising in tailoring the health benefits of secondary metabolites, underutilised in human’s nutrition due to their low stability and bioavailability.