Influence of Beef Hot Carcass Weight on Sensory Characteristics of Strip Loin, Eye of Round, and Denver Cut Steaks.

The objective of this research was to investigate the influence of beef hot carcass weight (HCW) on consumer sensory attributes. Beef carcasses (n = 116) were selected based on the USDA quality grade and HCW. Lightweight (LW; 296-341 kg), middleweight (MW; 386-432 kg), or heavyweight (HW; 466-524 kg) carcasses with USDA Choice (LC) or USDA Select (SEL) quality grades were used in this study. Carcasses were tracked through fabrication and the semitendinosus, chuck roll, and strip loin were collected and fabricated into eye of round, Denver cut, and strip loin steaks, respectively, for consumer sensory evaluation. USDA Select MW Denver cut steaks had increased overall liking and texture liking scores and were more tender and juicier than the SEL LW steaks (p ≤ 0.02). USDA Select MW strip loin steaks had increased overall and flavor liking scores and were more tender than the SEL LW steaks (p ≤ 0.02). USDA Choice MW eye of round steaks had increased overall, flavor, and texture liking scores and were juicier than the LW eye of round steaks (p ≤ 0.04). The steaks evaluated in this study were differentially impacted by HCW and little to no clear pattern of effects could be determined across cut or quality grade. Additional research is needed to determine the most acceptable HCW from a consumer perspective.

Effect of inclusion of distillers grains with solubles and crude glycerin in beef cattle finishing diets on ruminal fermentation and fatty acid biohydrogenation.

An experiment was conducted to evaluate the impact of feeding bio-fuel co-products on ruminal fermentation characteristics and composition of omasal digesta flow. Four ruminally cannulated Holstein steers (371 ± 5 kg) were used in a 4 × 4 Latin Square design. Omasal sample collection and triple marker technique was used to quantify fatty acid omasal flow. Treatments were applied as a 2 × 2 factorial where a steam flaked corn (SFC) basal diet (DGS-N CG-N) was replaced with 40% of diet DM as corn distillers grains (DGS; DGS-Y CG-N) or 10% of diet DM as crude glycerin (DGS-N CG-Y) or 40% of diet DM distillers grains and 10% of diet DM as crude glycerin (DGS-Y CG-Y). No effects were observed for the interaction of DGS and glycerin on measured rumen characteristics. Dietary inclusion of glycerin decreased (P = 0.05) ruminal content 4-h post feeding on a DM basis but did not influence DMI (P = 0.64). Feeding DGS had no effect (P = 0.34) on particulate passage to the omasum (kg/d) in spite of greater (P = 0.04) DMI. Feeding DGS reduced flow rate (% of rumen volume/h) (P = 0.05) but did not affect total VFA concentration (P = 0.46) or average ruminal pH (P = 0.72). No differences (P > 0.05) were observed in ruminal parameters when feeding glycerin, besides ruminal particulate content (kg) on DM basis (P = 0.05). An interaction of DGS and glycerin affected intake of stearic (P < 0.01), linoleic (P < 0.01), and linolenic acid (P < 0.01). An interaction of DGS and glycerin did not affect individual fatty acid flow with respect to intake for stearic (P = 0.17), linoleic (P = 0.18), or linolenic acid (P = 0.66). Dietary inclusion of glycerin had no impact on g of linolenic (P = 0.16) or linoleic (P = 0.32) acid transformed. A trend was identified for cattle fed diets with glycerin to have increased (P = 0.07) grams of conjugated linoleic acid (CLA; C18:2 cis-9, trans-11) per gram of linoleic acid intake, with no impact on the percent of saturated fat (P = 0.44) or unsaturated fat (P = 0.43) in omasal flow. For cattle fed diets with DGS, fewer grams of linoleic (P < 0.01) and linolenic (P < 0.01) were present in digesta flow per gram of intake. Inclusion of DGS in the treatment diets also increased (P < 0.01) stearic acid flow (g) and CLA flow (g) per gram of stearic and linoleic acid intake, respectively. Observed differences in CLA proportion post fermentation may indicate interrupted biohydrogenation when glycerin is fed.

Inclusion of corn grain in cattle diets increases the dietary concentration of unsaturated fatty acids like linoleic acid. Ethanol co-products are most often made from corn grain in the United States and contain concentrated amounts of unsaturated fatty acids. Concerns with feeding ethanol co-products could arise for cattle producers because the increased unsaturated fat concentration of meat products can lead to shorter meat shelf life. Co-products from bio-diesel production, such as crude glycerin, can be used to replace grain and reduce total unsaturated fat without affecting dietary energy. This study evaluated the effect of ruminal microbes to transform unsaturated fatty acids to saturated fatty acids in diets where steam-flaked corn was replaced by co-products such as distillers grains and crude glycerin. When steam-flaked corn is replaced with distillers grains in beef cattle diets, the fat composition was shifted to a higher proportion of saturated fatty acids due to increased biohydrogenation by ruminal microbes. However, feeding crude glycerin in place of steam-flaked corn increased conjugated linoleic acid, an intermediate product of the fatty acid transformation pathway. Increased conjugated linoleic acid indicates glycerin may impact the ability of microbes to transform linoleic acid to a saturated form.

Effect of caprylic acid alone or in combination with peracetic acid against multidrug-resistant Salmonella Heidelberg on chicken drumsticks in a soft scalding temperature-time setup.

The antimicrobial efficacy of caprylic acid (CA), a medium-chain fatty acid, against multidrug-resistant Salmonella Heidelberg (MDR SH) on chicken drumsticks in a soft-scalding temperature-time setup was investigated. Based on the standardization experiments in nutrient media and on chicken breast fillet portions, intact chicken drumsticks were spot inoculated with MDR SH and immersed in water with or without antimicrobial treatments at 54°C for 2 min. The treatments included 0.5% CA, 1% CA, 0.05% peracetic acid (PAA), 0.5% CA + 0.05% PAA, and 1.0% CA + 0.05% PAA. Additionally, the efficacy of the potential scald treatments against MDR SH survival on drumsticks for a storage period of 48 h at 4°C was determined. Furthermore, the effect of these treatments on the surface color of the drumsticks was also evaluated. Appropriate controls were included for statistical comparisons. The antimicrobial treatments resulted in a significant reduction of MDR SH on drumsticks. For the lower inoculum (∼2.5 log10 CFU/g) experiments, 0.5% CA, 1% CA, 0.05% PAA, 0.5% CA + 0.05% PAA, and 1.0% CA + 0.05% PAA resulted in 0.7-, 1.0-, 2.5-, 1.4-, and 1.5- log10 CFU/g reduction of MDR SH on drumsticks, respectively (P < 0.05). The same treatments resulted in 0.9-, 1.3-, 2.5-, 2.2-, and 2.6- log10 CFU/g reduction of MDR SH when the drumsticks were contaminated with a higher inoculum (∼4.5 log10 CFU/g) level (P < 0.05). Moreover, the antimicrobial treatments inactivated MDR SH in the treatment water to undetectable levels, whereas 2.0- to 4.0- log10 CFU/mL MDR SH survived in the positive controls (P < 0.05). Also, the treatments were effective in inhibiting MDR SH on the drumsticks compared to the respective controls during a storage period of 48 h at 4°C; however, the magnitude of reduction remained the same as observed during the treatment (P < 0.05). Additionally, none of the treatments affected the color of the drumsticks (P > 0.05). Results indicate that CA could be an effective natural processing aid against MDR SH on chicken products.

Application of plant extracts to improve the shelf-life, nutritional and health-related properties of ready-to-eat meat products.

Plant extracts are increasingly becoming important additives in food industry due to their antimicrobial and antioxidant abilities that delay the development of off-flavors and improve the color stability in ready-to-eat (RTE) meat products. Due to their natural origin, they are excellent candidates to replace synthetic molecules, which are generally considered to have toxicological and carcinogenic effects. The efficient extraction of these antioxidant molecules from their natural sources, along with the determination of their activity in the commercialized products, have been a great challenge for researchers and food chain contributors. The objective of this review is to highlight the application of plant extracts to improve the shelf-life, nutritional and health-related properties of RTE meat products. The sensory effects of these extracts on RTE meat products as well as the possible synergistic effects of a combination of extracts are discussed.

Survival of porcine reproductive and respiratory syndrome virus in fresh pork.

Porcine reproductive and respiratory syndrome virus (PRRSV) remains one of the most economically important diseases of pigs. Transmission of PRRS virus has been reported through many routes, with aerosol route being the most predominant. There may also be a potential risk of transmission through contami-nated pork, but this has never been investigated. The purpose of this study was to experimentally contaminate fresh pork with three different concentrations of PRRSV and to study virus survival at ambient (25 °C), refrigerated (4 °C), and frozen (-20 °C) temperatures. Concentrations of virus representing natural infectivity level and 'worst case scenario' were studied. The virus was detected in fresh pork at all three virus concentrations for up to 48 h at ambient temperature. At 4 °C, the virus survived for 6 days in pork inoculated with the higher virus concentration and for 3 days in pork inoculated at the lower concentration. At frozen temperature, PRRSV was detected for up to 60 days in pork inoculated at the higher concentration and for 7 days in pork inoculated at the lower concentration. These results suggest that fresh pork has the potential to be a vehicle for virus dissemination depending upon temperature and time of storage.

Survival of Porcine Reproductive and Respiratory Syndrome Virus in Pork Products.

There is a risk of virus transmission through contaminated pork, and many viruses are considered potential hazards for both humans and livestock. The risk of transmission may be elevated with importation/exportation of meat between countries globally. Survival of porcine reproductive and respiratory syndrome virus (PRRSV) in different pork products has not been studied. The present study evaluated PRRSV survival in four different products: fresh sausage, ham, bacon, and acidified sausage prepared with experimentally contaminated pork. These products were prepared according to standard methods used by the manufacturers of pork products, and then stored at room temperature, 4 °C and -20 °C. PRRSV was detected only in fresh sausage for up to 15 days at 4 °C and for 30 days at -20 °C. No PRRSV was detected at any temperature in any of the other three products. These preliminary data provide valuable information for the pork processing industry, as well as in planning for import/export of these products among different countries.

Effect of temperature on the survival of porcine circovirus type 2b in fresh pork.

Porcine circovirus type 2b (PCV2b) causes PCV-associated disease in pigs. This study was conducted to investigate the effect of temperature on the survival of PCV2b in fresh pork. Several pieces of longissimus dorsi muscle were injected with 100 µL of a suspension containing 10(5.2) TCID50 (50% tissue culture infective doses) of the virus. Virus-inoculated pieces of pork were stored at 25 °C, 4 °C and -20 °C and tested for the presence of infectious virus after different times of storage. PCV2b was found to survive in fresh pork for up to 2 days post inoculation (dpi) at room temperature, for 6 dpi at 4 °C and for up to 30 dpi at -20 °C indicating that the survival of PCV2b in fresh pork depends on temperature of storage.

Impact of management practices and distillers' grains feeding on the prevalence of Escherichia coli O157 in feedlot cattle in Minnesota.

Escherichia coli O157 is a foodborne pathogen that can be transmitted by contaminated ground beef and is shed naturally in cattle feces. Recent reports indicated that feeding distillers' grains (DG) to cattle increased fecal shedding and prevalence of E. coli O157. In Minnesota, feeding DG with solubles (DGS) to livestock became widespread within the last 10 years, but there is no report about the prevalence of E. coli O157 in beef cattle in this state. This study was undertaken to survey the fecal prevalence of E. coli O157 in cattle fed diets containing DG and its association with environmental conditions and management practices. Fecal samples were collected from three feedlots during a 1-year period. All animals in those feedlots were fed different DGS levels. E. coli O157 presence was determined using a combination of enrichment, immunomagnetic separation, plating onto sorbitol MacConkey agar, and confirmation of isolates by immunoassay and multiplex virulence genes polymerase chain reaction analysis. Overall, E. coli O157 was confirmed in 9.7% of samples. Prevalence during summer was 30% and declined to less than 10% the rest of the year. In animals grouped by dietary DGS concentration, no significant difference in prevalence (12.0 and 5.5%) was detected between the low and the high average groups (less and more than 20%). Previous feeding of DGS before arriving to the feedlot also had no influence on fecal prevalence. The presence of several interacting variables, uncontrolled in a real-life feedlot environment, was the likely reason for our observation and suggested that at the levels studied, DGS had no effect on the STEC O157 prevalence in cattle populations.

Effects of oregano oil brine enhancement on quality attributes of beef longissimus dorsi and semimembranosus muscles from various age animals.

UNLABELLED: The study reports whether or not oregano oil can reduce lipid oxidation and evaluate palatability variations in beef longissimus dorsi and semimembranosus muscles from various age animals (approximately 18 mo; 18 M, 30 to 60 mo; 30 M, and >60 mo; 60 M). Six muscles of each age group were halved and enhanced with a control brine containing no antioxidants (CN) or a brine containing oregano oil (OR), cut into steaks, and stored in modified atmosphere packaging for 0, 4, 7, and 11 d. Each sampling day, surface color (Minolta L, a, b), lipid oxidation (TBARS), cook yield, sensory analysis, and Warner-Bratzler shear force (WBSF) were measured. OR enhancement decreased TBARS values and slowed the rate of decline in a values (P < 0.05), but had no effect on WBSF, or sensory tenderness and juiciness scores (P > 0.05) compared to CN steaks. OR steaks had less rancidity detection, more off-flavor, lower overall acceptability in sensory analysis (P < 0.05). This indicated oregano oil can effectively reduce lipid oxidation and extend shelf-life of meat products, but further investigation would be needed to avoid off-flavor and acceptability of product quality. PRACTICAL APPLICATION: Decreases in meat consumption have led the meat industry to become more innovative in product development. Reducing lipid oxidation is a viable method to reduce rancidity, and improving product acceptability. Our research indicated that although oregano oil did reduce lipid oxidation, the adverse effects of flavor were too great, and thus would not be tolerable in fresh meat products at this concentration. However, there is potential to use oregano oil at lower concentrations and in a variety of processed products which could be beneficial to further the use of natural antioxidants.