Emergence of fatal avian influenza in New England harbor seals.

UNLABELLED: From September to December 2011, 162 New England harbor seals died in an outbreak of pneumonia. Sequence analysis of postmortem samples revealed the presence of an avian H3N8 influenza A virus, similar to a virus circulating in North American waterfowl since at least 2002 but with mutations that indicate recent adaption to mammalian hosts. These include a D701N mutation in the viral PB2 protein, previously reported in highly pathogenic H5N1 avian influenza viruses infecting people. Lectin staining and agglutination assays indicated the presence of the avian-preferred SAα-2,3 and mammalian SAα-2,6 receptors in seal respiratory tract, and the ability of the virus to agglutinate erythrocytes bearing either the SAα-2,3 or the SAα-2,6 receptor. The emergence of this A/harbor seal/Massachusetts/1/2011 virus may herald the appearance of an H3N8 influenza clade with potential for persistence and cross-species transmission. IMPORTANCE: The emergence of new strains of influenza virus is always of great public concern, especially when the infection of a new mammalian host has the potential to result in a widespread outbreak of disease. Here we report the emergence of an avian influenza virus (H3N8) in New England harbor seals which caused an outbreak of pneumonia and contributed to a U.S. federally recognized unusual mortality event (UME). This outbreak is particularly significant, not only because of the disease it caused in seals but also because the virus has naturally acquired mutations that are known to increase transmissibility and virulence in mammals. Monitoring the spillover and adaptation of avian viruses in mammalian species is critically important if we are to understand the factors that lead to both epizootic and zoonotic emergence.

Immunological aspects of polymer microsphere vaccine delivery systems.

In vitro studies using dendritic cells have identified that microencapsulated antigens are taken up and processed differently as compared with soluble proteins, and these findings have been reviewed. Similarly, in vivo, it is evident that microencapsulated materials have different properties in terms of uptake and trafficking. Intranasal (IN) instillation of encapsulated protective antigen resulted in a significant increase in the percentage of activated CD4+ and B-cells in the spleens of immunised mice, whereas IN instillation of soluble antigen failed to do so. This corroborates earlier findings concerning the uptake and trafficking of microparticles following bronchopulmonary administration. These data support the tenet that microencapsulation serves to modify the uptake, trafficking and processing of antigens.

Efectos de la suspensión no convencional de las canales en la palatabilidad de la carne de toretes / Effect of non-conventional of carcass suspension in the palatabilidad of bullock beek

La utilización de un método no convencional de suspender la canal vacuna mejoró significativamente las notas de terneza, y de satisfacción total aumentó el largo de los sarcomeros y disminuyó los valores de fuerza de corte o de cizalla en muestras provenientes de canales de los cuatro grupos de beneficio conciderados. La suspensión por el agujero obturador no mejoró significativamente las notas de terneza o de satisfacción total de las muestras de canales britanicas o sus cruzamientos en los grupos de 9-, 12- ó 18- meses de edad. La suspensión no convencional mejoró todas las notas de terneza y de satisfacción total de muestras provenientes de canales Brahman o sus cruzamientos en los cuatro grupos de edad al beneficio. En algunos casos, el mejoramiento alcanzó hasta 37.9 por ciento. Sin embargo, el mejoramiento mostró la tendencia de disminuir con avances en la edad. La suspensión por el agujero obturador disminuyó significativamente los valores de fuerza de corte o cizalla y aumentó significativamente el largo del sarcomero en tres de los cuatro grupos de edad al beneficio. De acuerdo con los resultados obtenidos, pueden inferirse que la suspensión de la cual por el agujero abjurador mejora significativamente la palatabilidad de la carne de toretes, dentro del rango aquí estudiado (9-18 meses). El mayor efecto de la suspensión no-convencional en mejorar la terneza se logró en aquellas canales que fueron las menos tiernas y menos satisfactorias en palatabilidad total . Además, la suspensión por el agujero obturador tendió a reducir la variabilidad en terneza existente entre los cuatro grupos ..

Tenderness of major muscles from three breed-types of cattle at different times-on-feed.

Seventy-five steers (9 to 12 months of age) of Angus (n = 25), Brahman (n = 25) and Brahman × Angus (n = 25) breed-types of known history were fed a high-energy diet and five steers from each breed-type were slaughtered after 0, 56, 112, 168 and 224 days on test. At seven days post mortem, the left side of each carcass was fabricated and eight major primals or subprimals were obtained. Steaks were removed from the shoulder clod, strip loin, tenderloin, top sirloin, knuckle, top round, bottom round and eye of round for Warner-Bratzler shear (WBS) determinations and from the strip loin and bottom round for sensory panel evaluations. Steaks from Angus and Brahman × Angus steers were generally more tender than steaks from Brahman steers. Tenderness of steaks from steers of the three breed-types responded to time-on-feed differently: (a) steaks from Brahman steers improved (P < 0·05) in tenderness with increasing time-on-feed for all muscles except the M. psoas major (tenderloin); (b) with the exception of the M. longissimus muscle (strip loin), the tenderness of steaks from Angus steers did not change (P > 0·05) as time-on-feed increased and (c) for the Brahman × Angus steers, five of the ten muscles studied improved (P < 0·05) in tenderness with increasing time-on-feed. 'Acceptable' tenderness (WBS values of less than 4·5 kg) for most of the muscles was achieved at feeding periods from 112 to 224 days for Brahman, from 0 to 56 days for Angus and from 56 to 168 days for Brahman × Angus.

Carcass characteristics and composition of Brahman, angus and Brahman x Angus steers fed for different times-on-feed.

Twenty-five steers of each of three breedtypes (Angus, Brahman and F(1) Brahman x Angus) were sorted by frame size and muscle thickness, assigned to groups (five steers of each breedtype) to be fed for 0, 56, 112, 168 or 224 days, slaughtered and compared for various carcass traits. Steers of each breedtype had similar dressing percentages. Carcasses from all three breedtypes merited similar USDA quality and yield grades; breedtypes differences in quality grade were slight. Differences were found in the fat deposition patterns exhibited by the three breedtypes. Brahman steers tended to deposit more of their total fat as subcutaneous fat early in the feeding period. Angus steers had more (P < 0·05) seam fat as a percentage of carcass weight at all five feeding periods and more (P < 0·05) kidney, pelvic and heart fat at two of the five feeding periods than Brahman steers. Brahman steers had a higher percentage of their separable lean in the muscles of the round than did steers of the other breedtypes.

USDA yield grades and various carcass traits as predictors of carcass composition.

Twenty-five carcasses from each of three breedtypes (Brahman, Angus and Brahman × Angus) were physically separated into fat, lean and bone. Several muscles from the round and the femur were used to derive equations to predict carcass composition and muscle-to-bone ratio. The femur (as a percentage of the carcass) was shown to predict percentage carcass bone with 90% accuracy. All of the muscles studied were highly related to total carcass lean but the percentage of carcass as M. biceps femoris was the best single muscle indicator of carcass lean of the muscles studied. More variation in carcass lean could be accounted for by a multiple regression equation, involving all four muscles studied, than by any single muscle. M. biceps femoris-to-femur ratio was found to predict carcass muscle-to-bone ratio with a high degree of accuracy. The USDA yield grades were found to be reliable indicators of carcass composition. A two-variable equation involving adjusted fat thickness and biceps femoris accounted for 88·6% of the variation (RSD = 1/·64) in percentage of carcass as separable lean.

Physical, chemical, histological and palatability characteristics of muscles from three breed-types of cattle at different times-on-feed.

Forty-five steers (9-12 months of age) of Angus (n =15), Brahman (n = 15) and Brahman × Angus (n = 15) breed-types were fed a high-energy diet and then slaughtered after 0, 112 or 224 days of feeding. At 7 days post mortem, the M. longissimus and M. biceps femoris were removed from the left side of each carcass and steaks were obtained for determination of sensory panel ratings, Warner-Bratzler shear force, sarcomere length, collagen content and collagen solubility. Tenderness ratings of steaks from the M. longissimus and M. biceps femoris from Angus were generally higher than ratings for steaks from Brahman or Brahman × Angus steers. Steaks from Brahman × Angus received higher tenderness ratings than steaks from Brahman steers in only a few comparisons. The three breed-types of cattle responded to time-on-feed differently; Brahman cattle needed to have been fed longer than Angus cattle to produce equally tender beef. With increased time-on-feed, M. longissimus tenderness increased for all breed-types, but M. biceps femoris tenderness was not related to time-on-feed. Few significant differences were observed among breed-types and among time-on-feed periods for collagen content or collagen solubility. Tenderness differences were closely correlated with the contractile state of the muscle which, in turn, was associated with weight, subcutaneous fat thickness and temperature decline of the carcass.

Effect of temperature and pH on the post-mortem degradation of myofibrillar proteins.

Incubation of bovine muscle at 37°C promoted a more drastic proteolytic change in myofibrillar proteins, as determined from sodium dodecyl sulphate polyacrylamide gels of isolated myofibrils, than incubation at 4°C. Degradation of myosin and troponin-T were the most noticeable changes at 37°C. Loss of α-actinin was observed in the 4°C incubated muscle. Ground bovine muscle incubated at pH 5·4 and 7 revealed that alterations in myosin and troponin-T were the most noticeable changes at ph 5·4 while troponin-T and α-actinin were altered at pH7. More troponin-T degradation occurred at pH 5·4 and 37°C than at pH7 and 4°C (similar to the degradation of myosin), indicating that troponin-T degradation in post-mortem muscle may be an indicator of overall myofibrillar proteolysis and not responsible for post-mortem tenderisation per se. Myosin degradation in the ground samples incubated at pH 5·4 and in whole samples incubated at 37°C was compared with the digestion of myofibrillar myosin by papain. Both pyrophosphate and Guba-Straub extracts of the 37°C and pH 5·4 treated samples confirmed that myosin degradation did occur to a much greater extent at this temperature and pH than at 4°C and pH7, and, in addition, at pH 5·4 frequent cleavage occurred near the papain sensitive site of myosin.

Muscle: Bone ratios in beef rib sections.

Thirty-eight steers and thirty heifers (14 to 17 months of age, from F(1) Hereford × Brahman cows bred to Angus or Hereford bulls), were either forage-fed for 123 days on millet-bermudagrass pasture or grain-fed for 90 days on a high-concentrate diet and were then commercially slaughtered. Warm carcass weights ranged from 167·8 kg to 324·3 kg. At 24 h post mortem, Texas Agricultural Experiment Station personnel (1) assigned scores or took measurements on each carcass for all factors used in yield grading and quality grading, (2) measured the length of hind leg (HL) and carcass length (CL) and (3) assigned a score for carcass muscling (MS) and, as appropriate, made an adjusted longissimus muscle area (ALA) evaluation. The 9th-10th-11th rib section from one side of each carcass was physically separated into longissimus muscle, fat, 'other soft tissue' and bone and ether extract determinations of the longissimus muscle and 'other soft tissue' components were made and used to adjust the yields of each of these components to a fat-free basis. Muscle to bone ratios ranged from 2·38 to 4·37. With both age and carcass weight held constant, diet, breed and sex explained only 35·8% of the variation in muscle to bone ratio. The best simple correlation with muscle to bone ratio was ALA/CL (r = ·59). Other measures significantly correlated with muscle to bone ratio included ALA (r = 0·55), MS (r = 0·50) and carcass weight (r = 0·49). Multiple regression analyses identified a three-variable subset comprised of ALA, carcass weight and CL which was related (P < 0·01) to muscle to bone ratio R(2) = 0·41). Data suggest that muscle to bone ratios differ widely among beef carcasses of similar genetic-management history and that there are carcass measures useful for predicting muscle to bone ratio.

Singular and combined effects of electrical stimulation, post-mortem ageing and blade tenderisation on the palatability attributes of beef from young bulls.

Thirty Santa Gertrudis bulls (approximately 15-18 months old) were slaughtered, dressed and split into siides. The right side of each carcass was electrically stimulated (ES) with seventeen impulses (1·8s impulse duration; 1·8s interval between impulses) of 550 V (AC) and 5 A while the left side served as a non-stimulated control (not-ES). At 24h post morten, USDA quality and yield grade data were obtained from each side. On the second day post mortem, all sides were fabricated and strip loins, top sirloin butts and ribeyes were obtained from each side for post-mortem ageing and blade tenderisation studies. Steaks were removed after a post-mortem ageing period of 4 or 18 days and before (not-BT) or after blade tenderisation (BT) for sensory panel evaluations or shear force determinations. ES sides had more youthful lean maturity (P < 0·0001), higher marbling (P < 0.·002), higher USDA quality grades (P < 0·0.0001) and finer-textured lean (P < 0·002) than did not-stimulated (not-ES) sides. ES significantly improved (P < 0·05) palatability traits in two of twenty-four comparisons; BT significantly improved palatability traits in twelve of twenty-four comparisons and 18-day post-mortem ageing significantly improved palatability traits in seven of twelve comparisons. No significant reductions (P < 0·05) in shear force values were observed for steaks from ES versus not-ES sides while significant reductions (P < 0·05) were observed for steaks from BT versus non-BT cuts (four of six comparisons) and for steaks from cuts aged for 18 versus 4 days (ten of twelve comparisons). BT and 18-day post-mortem ageing were more effective for increasing palatability or for decreasing shear force requirements than was ES; however, ES greatly improved lean colour of meat from bulls.

Feeder cattle frame size, muscle thickness and subsequent beef carcass characteristics.

Sixty feeder steers were assigned scores for frame size (small, medium or large) and muscle thickness (No. 1, No. 2 or No. 3), fed for 112 days and slaughtered. Grade data were collected for all 60 carcasses; 12 sides (four from each muscle thickness group) were fabricated into boneless, closely trimmed retail cuts and the 12 rounds from each of these sides were also physically separated into muscle, fat and bone. Marbling score and USDA quality grade varied inversely (P < 0·05) with frame size. Carcass quality grades were: 33·3% Choice; 67·7% Good and 0·0% Standard for small-framed cattle; 30·3% Choice, 42·4% Good and 27·3% Standard for medium-framed cattle and 5·5% Choice, 66·7% Good and 27·8% Standard for large-framed cattle. Analysis of variance showed significant (P < 0·05) differences among all muscle thickness groups in the longissimus muscle area and carcass weight but no difference in yield grade between the No. 1 and No. 3 muscle thickness groups; the larger mean longissimus muscle area of carcasses from steers in the No. 1 muscle thickness group was offset by their heavier carcass weight and their greater thickness of fat over the longissimus muscle. However, when analysis of covariance was used to hold fatness or fatness and frame size constant, the difference in yield grade between muscle thickness groups No. 1 and No. 3 was significant (P < 0·05). Also, carcasses from cattle assigned muscle thickness scores of No. 1, as feeders, had the highest (P < 0·05) muscle to bone ratio of the round (4·1 to 1) while carcasses from cattle assigned thickness scores of No. 3, as feeders, had the lowest (P < 0·05) muscle to bone ratio of the round (3·4 to 1).

Performance, carcass and palatability characteristics of Longhorn and other types of cattle.

Performance, carcass and palatability characteristics of Longhorn steers were compared with those of cattle currently popular in the United States-Hereford, Angus, Brahman, Holstein, two-breed crossbred (British beef breed crosses) and three-breed crossbred (1 4 dairy , 1 4 British beef and 1 2 European beef ) steers. Steers were fed roughage, then a growing diet (42 days), then a high energy (89% concentrate) diet (153 to 179 days by breed group) and slaughtered, individually, at USDA Choice finish or, failing that, after 186 days on the finishing diet. Data suggest that Longhorns, compared with types of cattle currently used: (1) are less desirable in physical appearance; (2) gain weight less rapidly, reaching the desired finish and slaughter weight as older animals; (3) convert feed to liveweight less efficiently; (4) deposit less subcutaneous fat, more internal fat, but essentially the same amount of intramuscular fat; (5) are as muscular (longissimus muscle area, estimated percentage of carcass muscle, muscle to bone ratio, muscle to fat ratio); (6) are as desirable in USDA quality grade and yield grade and (7) produce beef that is a palatable.

Effect of post-mortem time and temperature on bovine intramuscular collagen.

A section of longissimus muscle was excised from six steers within 1 h post mortem. Half of the muscle section from each animal was held at 37°C (HT) and the other half was maintained at 1°C (C). Samples were collected from each muscle section in each treatment at 12 and 24 h to study the effect of conditioning temperature and incubation time on collagen properties by comparing the per cent soluble collagen and the relative distribution of collagen components. More of each collagen component (α(1), α(2), ß(11) and ß(12)) was present on SDS gels of samples incubated for 24 h versus 12 h. Although the collagen solubility did not increase to a great extent in the HT conditioned samples when compared with C samples, the HT treatment increased the effect of post-mortem ageing (i.e. more collagen molecules were solubilised and entered the gel during electrophoresis). Each collagen component, expressed as a percentage of total collagen, remained relatively constant when comparing different temperatures or post-mortem times. This indicates that the increase in collagen components being absorbed on the gels of 24 h post-mortem samples is mainly caused by an increase in the release of total collagen from the connective tissue matrix and not by the specific release of any one component. It was also found that some breakage of collagen crosslinks occurred during high temperature conditioning. No change in type III collagen of intramuscular connective tissue was found in this study.

Effects of Sodium Nitrite, Sodium Acid Pyrophosphate and Meat Formulation on Properties of Irradiated Frankfurters.

Frankfurters of twelve treatment combinations were made using a conventional manufacturing procedure. Manufacturing treatments included formulations of either 60% pork/40% beef, 100% mechanically deboned chicken (MDC) or 100% mechanically deboned turkey (MDT); sodium nitrite levels of 0 or 50 ppm; and sodium acid pyrophosphate (SAPP) levels of 0 or 3,750 ppm. Finished frankfurters were either not irradiated or irradiated at temperatures of either -34.4 or -51.1°C and at a dose level of 0.8 or 3.2 Mrad. Addition of SAPP did not significantly affect external or internal color, off-flavor incidence or overall palatability of any of the frankfurters but significantly increased processing shrinkage for pork/beef and chicken franks, decreased frankfurter pH values for pork/beef and chicken franks and improved texture of pork/beef, chicken and turkey franks. Addition of 50 ppm nitrite, as compared to use of no nitrite, significantly decreased processing shrinkage of turkey franks, increased batter and frankfurter pH of pork/beef franks, increased consumer cooking loss of chicken franks but decreased consumer cooking loss of turkey franks, decreased off-flavor of pork/beef, chicken and turkey franks, and improved internal color of pork/beef, chicken and turkey franks. An irradiation temperature of -51.1°C as compared with -34.4°C, decreased off-flavor intensity and increased palatability of pork/beef franks but did not affect other properties of pork/beef franks or any of the properties of chicken or turkey franks. Franks irradiated with 0.8 Mrad differed (P<0.05) from those that were not irradiated in only 3 of 18 sensory traits (including overall palatability of pork/beef franks); franks irradiated with 3.2 Mrad differed (P<0.05) from those which were not irradiated in 8 of 18 sensory traits (including overall palatability of pork/beef, chicken and turkey franks).

Cooked Product Temperature and Curing Ingredients Affect Properties of Irradiated Frankfurters.

Frankfurters (9.07-kg batches) were conventionally made in which three replications of the following treatment combinations were used (a) curing ingredients: 0 or 50 ppm of sodium nitrite, 75 ppm of sodium nitrite-25 ppm of sodium nitrate, or 50 ppm of sodium nitrite-25 ppm of sodium nitrate, (b) seasoning: dry soluble or equivalent ground spice, (c) cooked product temperatures of 65.5 or 76.6 C and (d) radiation processing levels of either 0, 0.8 or 3.2 megarads. Regardless of curing ingredient combinations or levels of irradiation, lowering internal cooked product temperatures (65.5 vs. 76.6 C) improved internal color, off-odor, off-flavor, moistness and overall desirability scores of frankfurters. Use of a dry soluble seasoning in comparison to an equivalent natural ground spice seasoning had no effect on sensory, chemical or palatability traits of irradiated frankfurters. Although not significant, frankfurters made without nitrite (0-NO2) compared to those made with 75 NO2-25 NO3, had greater process shrinkage values and were significantly less desirable in visual color, off-flavor and overall palatability. External and internal color scores of frankfurters made with NO2 and NO3 combinations were less intensely pink, with an increase in irradiation from 0 to 0.8 to 3.2 megarads. Sensory traits (off-flavor, off-odor, texture and overall palatability) were less desirable in those frankfurters irradiated at 3.2 megarads as compared to those irradiated at 0.8 megarads. Both levels of irradiation produced less desirable frankfurters than the non-irradiated controls (0 megarads). Improvements in sensory properties of irradiated frankfurters may be accomplished by use of at least 50 ppm of NO2 and cooking to a final internal product temperature of 65.5 C.

Effects of Sodium Nitrite, Sodium Nitrate and DL, Alpha-Tocopherol on Properties of Irradiated Frankfurters.

Frankfurters were manufactured to contain certain combinations of curing ingredients (sodium nitrite, sodium nitrate and DL alpha-tocopherol). Some frankfurters were made to contain in the finished product 0% added moisture, others were made to contain 10% added moisture, some frankfurters were not irradiated (0-megarad), others were irradiated with either 0.8 or 3.2 megarads (Cobalt-60 radiation source). Use of DL, alpha-tocopherol (at a level of 206 ppm) was associated with greater processing shrinkage, more off-flavor and less overall palatability (P<0.05). The most desirable external and internal cured color and firmest texture was in frankfurters made with 50 ppm of NO2 or with 100 ppm of NO2, irrespective of irradiation level. Use of irradiation (0.8 or 3.2 megarads) on frankfurters made without nitrite or nitrate did not improve visually determined cured color but did improve this color when determined spectrophotometrically; nevertheless, cured color of irradiated frankfurters made without use of nitrite or nitrate was not comparable to that of non-irradiated or irradiated frankfurters made with 100 ppm NO2. Irrespective of added moisture or curing ingredient combinations, significant differences (P<0.05) in palatability traits were associated with increasing irradiation levels (0, 0.8 or 3.2 megarads). Off-flavor increased, texture was less firm and overall palatability was less desirable as irradiation level increased. Low-dose irradiation (⩽1 megarad) may be feasible for enhancing the palatability traits of frankfurters containing lower levels of nitrite (lower than 156 ppm) but it appears that the correct irradiation level would be lower than the 0.8 megarad used in this study.

Cooking at variable microwave power levels. Effects on energy use and quality of top round beef roasts.

Beef top round roasts weighing approximately 2.3 lb. each were cooked from the thawed and frozen states in a countertop microwave oven (115v; 2,450 mHz) at the cooking power levels of "high" (553 watts) and "simmer" (237 watts) and also in a conventional oven at 163 degrees C (325 degrees F). Cooking times, energy consumption, cooking losses, and palatability of cooked products were compared. In general, no notable advantages were found in cooking at microwave "simmer" vs. "high".

A comparison of heat-induced gel strengths of bovine plasma and egg albumen proteins.

The heat-induced gel strength in suspensions of two types of plasma protein isolates and egg albumen were compared to investigate the use of bovine blood plasma in food systems as a replacement for egg albumen and other proteins. A viscosity index, based on a counter-flow back-extrusion model, was used to measure gel strength. The optimum pH for gel formation was 7.0 for phosphated and nonphosphated plasma protein suspensions and 9.0 for egg albumen. The protein gel strengths were compared at 8% protein concentrations and at their respective pH optima. The gel strength of heated bovine plasma protein suspensions was greater (P < .01) than that of egg albumen, indicating that blood plasma exhibited a binding ability superior to that of egg albumen. The addition of controlled low levels of sodium and calcium increased (P < .05) the binding ability of both plasma protein isolates, while egg albumen showed no changes (P > .05). Greater concentrations substantially decreased (P < .01) the gel strength in both types of heated plasma protein suspensions and egg albumen, revealing that all three protein types exhibited an ionic strength dependency.

Influence of Certain Processing Steps on Attachment of Microorganisms to Pork Skin 1.

Pseudomonas putrefaciens and lactobacillus counts of inoculated pork skin obtained with the maceration method usually were higher than were those obtained with the rinse method. Scalding and dehairing and shaving caused extensive destruction of the test organisms when placed on the skin before these slaughter-dressing steps. Smaller decreases in count occurred during singeing and washing and during evisceration and washing. Increases in S value (log count by maceration method minus log count by rinse method) for P. putrefaciens and a Lactobacillus sp. after freezing-thawing of inoculated pork skin may be related to a higher death rate of bacteria in the water film than for those entrapped in skin crevices. P. putrefaciens and the Lactobacillus sp. that were attached to pork skin exhibited greater heat resistance than did those bacteria which were not attached to skin. During storage of inoculated pork skin, S values of P. putrefaciens and the Lactobacillus sp. increased; this increase probably reflects increased strength of attachment of bacteria to the skin. Scanning electron microscopy of inoculated pork skin showed the formation of extracellular structures which may play a role in attachment of bacteria to skin or meat surfaces.