Dissolved Copper, Nickel and Lead in Tampamachoco Lagoon and Tuxpan River Estuary in the SW Gulf of Mexico.

In order to estimate the effects of a thermal power plant, physicochemical parameters and the concentrations of copper, nickel and lead were evaluated in water from both Tampamachoco Lagoon and the estuary of the Tuxpan River. Average salinities were 33.66 ups in the lagoon area, 32.77 ups in the channel that joins the lagoon and the river, and 24.74 ups in the river estuary. Total average metal concentrations were 21.95 for Cu, 29.67 for Ni and 4.31 µ/L for Pb. Sampling point 1 and samples from the bottom water of the lagoon present the highest salinities and concentrations of suspended matter, TOC, Cu, Ni and Pb.These high values may be associated with the infiltration of sea water either from plant operation or from the channel that connects the lagoon with the sea.

Tcf4 transgenic female mice display delayed adaptation in an auditory latent inhibition paradigm.

Schizophrenia (SZ) is a severe mental disorder affecting about 1 % of the human population. Patients show severe deficits in cognitive processing often characterized by an improper filtering of environmental stimuli. Independent genome-wide association studies confirmed a number of risk variants for SZ including several associated with the gene encoding the transcription factor 4 (TCF4). TCF4 is widely expressed in the central nervous system of mice and humans and seems to be important for brain development. Transgenic mice overexpressing murine Tcf4 (Tcf4tg) in the adult brain display cognitive impairments and sensorimotor gating disturbances. To address the question of whether increased Tcf4 gene dosage may affect cognitive flexibility in an auditory associative task, we tested latent inhibition (LI) in female Tcf4tg mice. LI is a widely accepted translational endophenotype of SZ and results from a maladaptive delay in switching a response to a previously unconditioned stimulus when this becomes conditioned. Using an Audiobox, we pre-exposed Tcf4tg mice and their wild-type littermates to either a 3- or a 12-kHz tone before conditioning them to a 12-kHz tone. Tcf4tg animals pre-exposed to a 12-kHz tone showed significantly delayed conditioning when the previously unconditioned tone became associated with an air puff. These results support findings that associate TCF4 dysfunction with cognitive inflexibility and improper filtering of sensory stimuli observed in SZ patients.

Dry-cured ham restructured with fibrin.

The viability of a fibrinogen-thrombin system (FT) to bind fresh deboned hams for incorporation in the salting and ripening processes, to produce cured ham, was studied. The effects of the different processing variables (pH, NaCl concentration, temperature and gelation time) on FT, a meat emulsion mixed with FT, fresh pork portions and deboned hams restructured with FT were analyzed. The most stable and firmest fibrin gels were obtained after 6h of adding the FT, with less than 2% NaCl and pH 7-8.4. Scanning electron microscopy of the fibrin gel showed fibrillar structures with a high degree of cross-linking and a high density. Two structures were found in the binding area of restructured meat; one in the central part with similar characteristics to fibrin gels and, another in the area of contact between the meat surfaces, where a filamentous structure connected the fibrin gels with the muscle bundles.

Effect of E-beam treatment on the safety and shelf life of mayonnaise potato salad.

The radioresistance of Listeria monocytogenes, Salmonella enterica serovar Enteritidis, and S. enterica serovar Typhimurium has been studied in a complex matrix like mayonnaise potato salad. D(10)-values of 0.56, 0.32-0.35, and 0.41-0.42 kGy were calculated for each organism, respectively. Keeping in mind these values, the microbiological criteria, the characteristics of the microorganisms, and a shelf life of the products of 20 days stored at 4°C, an irradiation treatment of 1 kGy was calculated to reach the food safety objectives. A duplication of the shelf life is also achieved with a dose of 1 kGy. Mayonnaise potato salad radiated with doses of up to 2 kGy showed negligible off-sensory characteristics.

Lack of growth of Listeria monocytogenes and Staphylococcus aureus in temperature abuse of E-beam treated ready-to-eat (RTE) cooked ham.

The behaviour of Listeria monocytogenes and Staphylococcus aureus in vacuum-packed cooked ham slices treated with an electron beam and stored at 4, 7 and 10 degrees C was investigated. Cooked ham slices were inoculated with L. monocytogenes and S. aureus and electron beam treated at 2 and 3 kGy. After treatment, a long temperature-dependent death phase was observed, followed by growth at a slower rate than in untreated samples. Assuming a hypothetical load of 10 cells/g or cm(2) of L. monocytogenes and S. aureus as an original contamination in an industrial situation, an E-beam treatment of vacuum-packed cooked ham slices at 2 kGy guarantees the microbiological safety of the product along its shelf life, even if a noticeable temperature (10 degrees C) abuse occur during its storage period. Likewise, the E-beam treatment gave rise to a substantial increase of the RTE cooked ham shelf life off-sensory features associated to the spoilage only were detected in non-treated samples (controls) after 8 and 18 days of storage at 10 degrees C and 7 degrees C, respectively.

Microbial transglutaminase for cold-set binding of unsalted/salted pork models and restructured dry ham.

The viability of using microbial transglutaminase (MTGase) as a cold-set binder for restructuring and manufacturing deboned dry ham (RDH) was evaluated. The influence of meat pre-treatment, preparation of the MTGase, packing system and set temperature on the binding rate and force was tested using pork models and deboned legs. The best binding parameters were obtained when meat surfaces were evenly distributed with salts (NaCl, KNO(3), NaNO(2)) and then washed with a saline solution (W), afterwards powder (P) or liquid (L) MTGase was applied, and simultaneous salting and vacuum packing (S) set at 7 degrees C were performed. The RDH manufactured following these procedures (WPS and WLS) was stable during drying and could resist the handling and production process. Binding force increased (p<0.05) during 8 weeks of drying. Scanning electron microscopy analysis showed an increase of cross-links during the drying period of RDH related to the increase in binding force.

Distribution of dissolved trace metals around the Sacrificos coral reef island, in the southwestern Gulf of Mexico.

A reef system in the southwestern Gulf of Mexico is affected by anthropogenic activities, sourced by urban, fluvial, and sewage waters. Dissolved metals have higher concentrations during the rainy season. V and Pb, were derived from an industrial source and transported to the study area by rain water. On the other hand, Jamapa River is the main source for Cu and Ni, which carries dissolved elements from adjacent volcanic rocks. Principal Component Analysis shows a common source for dissolved nitrogen, phosphates, TOC, and suspended matters probably derived from a sewage treatment plant, which is situated near to the study area.

A comparison between E-beam irradiation and high pressure treatment for cold-smoked salmon sanitation: microbiological aspects.

The effectiveness of electron beam irradiation and high pressure treatment for the sanitation of cold-smoked salmon from two points of view, microbial safety and shelf-life extension, was compared. From the response of L. monocytogenes INIA H66a to irradiation, a D value of 0.51 kGy was calculated. For samples stored at 5 degrees C, 1.5 kGy would be sufficient to attain a Food Safety Objective (FSO) of 2 log(10)cfu/g L. monocytogenes for a 35-day shelf-life, whereas 3 kGy would be needed in the case of a temperature abuse (5 degrees C + 8 degrees C). Pressurization at 450 MPa for 5 min was considered to be an insufficient treatment, since the FSO of 2 log(10)cfu/g L. monocytogenes was only attained for a shelf-life of 21 days at 5 degrees C. However, treatment at 450 MPa for 10 min achieved this FSO for samples held during 35 days at 5 degrees C, or during 21 days under temperature abuse (5 degrees C+8 degrees C) conditions. Irradiation at 2 kGy kept the microbial population of smoked salmon below 6 log(10)cfu/g after 35 days at 5 degrees C, with negligible or very light changes in its odor. Pressurization at 450 MPa for 5 min also kept the microbial population below 6 log(10)cfu/g after 35 days at 5 degrees C and did not alter odor, but affected negatively the visual aspect of smoked salmon.

Safety and quality of ready-to-eat dry fermented sausages subjected to E-beam radiation.

The inactivation kinetics in the death of Listeriainnocua NTC 11288 (more radioresistant than five different strains of Listeriamonocytogenes) and Salmonella Enterica serovar Enteritidis and S. enterica serovar Typhimurium by E-beam irradiation has been studied in two types of vacuum-packed RTE dry fermented sausages ("salchichon" and "chorizo") in order to optimize the sanitation treatment of these products. A treatment of 1.29kGy was calculated to reach the food safety objective (FSO) according to the "zero tolerance" criterion for the three strains. No irradiation treatment was necessary to meet the 10(2)c.f.u./g microbiological criterion for L. monocytogenes. Dry fermented sausages treated with ⩽2kGy had negligible sensory (appearance, odour and taste) modifications. Therefore, this treatment produces safe dry fermented sausages with similar sensory properties to the non-irradiated product.

Elimination of Listeria monocytogenes from vacuum-packed dry-cured ham by E-beam radiation.

The inactivation kinetics for Listeria monocytogenes Scott A (CIP 103575, serotype 4b) and Listeria innocua (NTC 11288) after E-beam radiation were studied in vacuum-packed ready-to-eat dry-cured ham to optimize the sanitation treatment of this product. A treatment of 1.12 kGy was calculated to reach the food safety objective according to the U.S. Department of Agriculture criterion. No irradiation treatment is necessary to meet the European Union microbiological criterion for this bacterium. No changes (at doses < or =4 kGy) in the 2-thiobarbituric acid reactive substances values and texture were observed. Dry-cured hams treated with 1 and 2 kGy had negligible sensory modifications (appearance, odor, and flavor). However, the application of 3 and 4 kGy resulted in an increase in the intensity of off-odors and off-flavors. Despite these effects, all irradiated vacuum-packed dry-cured hams treated at < or =4 kGy were deemed acceptable for trading.

Raman spectroscopy study of the structural effect of microbial transglutaminase on meat systems and its relationship with textural characteristics.

Raman spectroscopy and texture analysis (TPA) studies were carried out to determine the effect of adding different levels of microbial transglutaminase (MTGase) to meat systems. This addition produced a significant (p<0.05) increase in hardness, springiness and cohesiveness in the meat systems. Raman spectroscopy analysis revealed the occurrence of secondary structural changes in meat proteins due to MTGase. Modifications in the amide I (1650-1680cm(-1)) and amide III (1200-1300cm(-1)) regions indicated a significant (p<0.05) decrease in α-helix content, accompanied by a significant (p<0.05) increase in ß-sheets and turns due to the addition of the enzyme to meat systems. Significant (p<0.05) correlations were found between these secondary structural changes in meat proteins and the textural properties (hardness, adhesiveness, springiness and cohesiveness) of meat systems.

Impact of feeding and rearing systems of Iberian pigs on volatile profile and sensory characteristics of dry-cured loin.

The effect of growing pigs on free-range (FR) or in confinement with three different diets [acorn (A), acorn and grass (A-G) and formulated diet (FD)] on composition, volatile profile and sensory characteristics of dry-cured loin was studied. The FR, A and A-G diets, in comparison with FD, induce a higher α- and γ-tocopherol concentration, which limits the TBARs values at 24h of air exposure. Sixty volatile compounds were identified in the headspace, including 14 aldehydes, 10 hydrocarbons, eight alcohols, five ketones, four furans, four pyrazines, four sulphur compounds, three acids, three esters, three phenols, one pyridine and one pyrrole. Volatiles from amino acid catabolism stressed the difference among batches FR being the batch with the highest level of these compounds. Products from FD showed the lowest fat content and L(∗) value. FR loins obtained the highest scores for appearance, odour and flavour in the rank order test sensory analysis.

Enrichment of dry-cured ham with α-linolenic acid and α-tocopherol by the use of linseed oil and α-tocopheryl acetate in pig diets.

The use of α-linolenic acid and α-tocopherol enriched pork on the fatty acids and the sensory characteristics of Spanish dry-cured hams have been studied. Five batches of hams were manufactured using the posterior legs of pigs fed on diets with the same ingredients except for the oil source: sunflower (C), linseed (L) or linseed and olive (1/1, w/w, LO). Two different α-tocopheryl acetate concentrations [20 (C, L and LO) or 220 (LOE and LE)mg/kg diet] were used. Biceps femoris and Semitendinosus/Semimembranosus muscles from hams with low polyunsaturated fatty acid n-6/n-3 ratio (less than 3) were obtained from animals fed on linseed and linseed/olive oil enriched diets. However, hams from animals fed on diets added with linseed and α-tocopheryl acetate (20mg/kg diet) (batch L) were rejected by consumers because of less acceptable sensory characteristics and higher TBARs. The remaining hams had satisfactory sensory and nutritional characteristics.

Tensile properties of cooked meat sausages and their correlation with texture profile analysis (TPA) parameters and physico-chemical characteristics.

The possibilities of using breaking strength (BS) and energy to fracture (EF) for monitoring textural properties of some cooked meat sausages (chopped, mortadella and galantines) were studied. Texture profile analysis (TPA), folding test and physico-chemical measurements were also performed. Principal component analysis enabled these meat products to be grouped into three textural profiles which showed significant (p<0.05) differences mainly for BS, hardness, adhesiveness and cohesiveness. Multivariate analysis indicated that BS, EF and TPA parameters were correlated (p<0.05) for every individual meat product (chopped, mortadella and galantines) and all products together. On the basis of these results, TPA parameters could be used for constructing regression models to predict BS. The resulting regression model for all cooked meat products was BS=-0.160+6.600∗cohesiveness-1.255∗adhesiveness+0.048∗hardness-506.31∗springiness (R(2)=0.745, p<0.00005). Simple linear regression analysis showed significant coefficients of determination between BS (R(2)=0.586, p<0.0001) versus folding test grade (FG) and EF versus FG (R(2)=0.564, p<0.0001).

Magnetic resonance imaging, rheological properties, and physicochemical characteristics of meat systems with fibrinogen and thrombin.

Magnetic resonance imaging (MRI) and textural and physicochemical analyses were carried out to evaluate the effect of fibrinogen and thrombin (Fibrimex) addition to meat systems formulated with and without NaCl. For this purpose, different model systems were elaborated: fibrinogen and thrombin (FT), meat emulsion (ME), and meat emulsion with fibrinogen and thrombin (MEFT), with 0, 1, and 2% of NaCl. The addition of fibrinogen-thrombin to meat emulsions results in a gel network with modified physicochemical and textural characteristics, increasing the hardness and springiness. The addition of NaCl at 2% to FT and MEFT systems reduced the gel hardness. MRI parameters (T2, T1, and apparent diffusion coefficient) indicated that systems with fibrinogen and thrombin (FT and MEFT) presented a structure with many and large pores, bulk water, and higher translational motion of water. Significant correlations were found between MRI, texture, and physicochemical parameters.

Breaking strength of dry fermented sausages and their correlation with texture profile analysis (TPA) and physico-chemical characteristics.

In order to assess its usefulness for monitoring textural properties of dry fermented sausages (chorizo, salchichon, salami, fuet and mini-fuet) the determination of breaking strength (BS) was evaluated. Texture profile analysis (TPA) and physico-chemical measurements (pH, aw, dry matter, fat content) were also performed. The BS determined by tensile test and TPA analysis produced complementary information that allowed these meat products to be grouped according to four different textural profiles. These profiles were characterized (p<0.05) by the values of BS, hardness, adhesiveness, cohesiveness and springiness. Multivariate analysis confirmed that BS and TPA parameters were correlated significantly (p<0.00005). On basis of these results, TPA parameters could be used to construct regression models to predict BS and therefore, to obtain a more complete textural property description of the dry fermented sausages. The resulting regression model was BS=-0.777+0.728∗adhesiveness-16881∗cohesiveness+1884.61∗springiness+0.042∗hardness (R(2)=0.634, p<0.00005).

Use of bacterial extracts to enhance amino acid breakdown in dry fermented sausages.

The effect of the intracellular cell-free extracts (ICFEs) of two bacterial strains (Lactobacillus sakei GO and Bacillus pumilus) on the amino acid catabolism and the sensory properties of dry fermented sausages, was investigated. Extracts were added to sausages alone or in combination with a protease, papain. Amino acid breakdown was monitored by the changes in free amino acids, ammonia and amine content during the ripening process. A 15% decrease in the content of free amino acids was observed in sausages added with the ICFE from L. sakei GO. Furthermore, the extract of L. sakei GO significantly reduced (54-68%) the content of the amino acids considered as precursors of the typical ripened flavour, i.e., valine, leucine and isoleucine. Chemical changes were not reflected in a significant improvement of the sensory quality of sausages added with the ICFEs. The potential use of the bacterial ICFEs studied in the present work for the manufacture of dry fermented sausages, and its comparison with the use of fungal extracts, are discussed.

Destruction of Salmonella Senftenberg on the shells of intact eggs by thermoultrasonication.

The combined effect of ultrasonic waves and heat treatment applied simultaneously was evaluated on the survival of strains of Salmonella Senftenberg on shells of intact eggs. This combined process has a higher killing effect than heat treatment alone. The decimal reduction times (D-values) were decreased by 65.2 to 11.1% in the temperature range studied (57.8 to 67 degrees C). In contrast to the effect on Salmonella enterica serovar Enteritidis in a previous study, thermoultrasonication had no important advantage for elimination of Salmonella Senftenberg. However, because 52 degrees C is a nonlethal temperature for Salmonella Senftenberg, the conditions used for the elimination of Salmonella Enteritidis (52 degrees C for 12 min) in the previous study would be equivalent to ultrasonic treatment alone in the present study. This thermoultrasonication treatment may result in a 100-fold greater reduction of Salmonella Senftenberg than that achieved by common in-shell egg pasteurization (60 degrees C for 3.5 min).