Increasing demands for natural, organic, and/or preservative-free foods have resulted in the consumer availability of uncured, no-nitrate/nitrite-added processed meat and poultry products. A comprehensive understanding about the quality and sensory attributes of commercially available uncured products is unclear. The objective of this study was to determine if quality and sensory differences exist between uncured and cured meat products. Five different commercial brands (Brands A to E; 4 uncured, no-nitrate/nitrite-added, and 1 nitrite-added) of 3 product types (hams, frankfurters, and bacons) were obtained from retail supermarkets. The samples were evaluated for color, pigment content, pH, lipid oxidation, residual nitrate and nitrite content, and consumer acceptance. All brands from all product types evaluated, except for 1 bacon (Brand B), had cured color, aroma, and flavor attributes similar to the nitrite-added control (Brand E). All product types and brands contained residual nitrate and residual nitrite except for Brands B and D bacons (< 1 ppm nitrite). Lipid oxidation as measured by 2-thiobarbituric acid reactive substances revealed a large variation in the occurrence of lipid oxidation both between and within product types, with frankfurters reporting the highest levels. Color measurements indicated the majority of the brands within each product type were similar to the control. Consumer sensory ratings for surface/lean color, aroma, flavor, texture, and overall acceptance determined that variation existed. Brand E (nitrite-added control) and 1 uncured, no-nitrate/nitrite-added brand for each product type were not different (P > 0.05) for overall acceptance and received higher scores (P < 0.05) than all other brands within each product type.

ABSTRACT: Fully‐cooked salmon and catfish fillets were treated by ionizing radiation (0, 3, or 6 kGy), high hydrostatic pressure (HHP) (0, 414, or 690 MPa), 2 different temperatures during pressurization (ambient‐HHP approximately equal to 21 °C, or heated‐HHP = 70 °C), and combinations of the treatments. Kramer shear values increased for salmon and catfish fillets treated by HHP, heated‐HHP, and a combination treatment. Tenderness and juiciness scores of salmon and catfish fillets were lower with HHP, heated‐HHP, and a combination treatment. Irradiation decreased CIE a* values of salmon, and CIE b* values of salmon and catfish. Irradiation increased tenderness and juiciness scores of salmon and increased flavor intensity of catfish.

Effects of irradiation (2 kGy) of ground beef patties from trimmings stored aerobically for 0 or 6 days on lean color, odor, and sensory attributes were investigated. Beef trimings were coarse ground and split into 2 groups. Group one was fine ground, pattied, and packaged immediately; group-two was stored 6 days then fine ground, pattied, and packaged. Irradiated beef patties had greater (P<0.05) off-odors, and off-flavors, lower (P<0.05) CIE L(∗), a(∗) and b(∗) and saturation indexes values (P<0.05) after four days of storage at 0±1 °C. Irradiation of patties produced from trimmings aged an extra 6 days resulted in increased (P<0.05) saturation indexes and b(∗) values, but not off-odors when compared to non-aged and irradiated patties. Thus, the production of irradiated beef patties should utilize beef trimmings with the shortest postmortem aging time and a dose of less than 2 kGy to minimize discoloration and off-odors.

Ground beef was irradiated to 0, 2, or 4 kGy and then inoculated with a mixed culture of four serotypes of salmonellae or five strains of Escherichia coli O157:H7. The ground beef was stored at either 15 or 25 degrees C, and the growth of the inoculated bacteria was monitored over time. Growth parameters were determined for both the salmonellae and the E. coli O157:H7 using the Gompertz equation. There was no significant difference in lag phase duration or generation time, irrespective of the dose to which the ground beef had previously been exposed. Furthermore, the lag phase durations and generation times determined in this study did not differ significantly from previously published values. This suggests that, although irradiation eliminates a significant portion of the spoilage microflora in ground beef, the absence of this microflora provides no competitive advantage to the growth of salmonellae or E. coli O157:H7 in ground beef.

ABSTRACT: Two varieties of oat fiber, each at 3 levels, were studied to determine effects of the oat fiber on quality characteristics of light bologna and fat‐free frankfurters. Seven treatments were formulated for each meat product: Control (0% oat fiber), 1% bleached oat fiber (BL), 2% BL, 3% BL, 1% high‐absorption oat fiber (HA), 2% HA, and 3% HA. Results indicated that addition of both types of oat fiber produced greater yields, and lighter, less red color. Purge was reduced with oat fiber at 3%. Product hardness increased for bologna with both fiber types. The extent of product change, however, was different for the 2 oat fiber varieties. Keywords: oat fiber, bologna, frankfurters, yield, color

ABSTRACT Effects of irradiation (2 kGy) of ground beef from trimmings aged 3, 6, or 9 days postmortem (PM) and packaged aerobically or anaerobically on lean color and aroma were investigated. Irradiation increased off‐odors and reduced color scores and Hunter a* (redness) and b* (yellowness) values (P < 0.05). Aerobic packaging increased (P < 0.05) off‐odors and Hunter L* (lightness) and b* values while reducing color scores and a* values. Irradiated patties made from trimmings of the shortest aged meat, 3‐days, had higher color scores and a* values, compared to irradiated samples aged 6‐ and 9‐days PM (P < 0.05). Irradiated patties packaged aerobically had more (P < 0.05) off‐odors, hue angle and L* and b* values and lower color scores and a* values when compared to irradiated anaerobic patties. Thus, irradiated beef patties should be made of short aged trimmings and anaerobically packaged to prevent discoloration and off‐odors.

Differences in product quality resulting from use of irradiation or thermal processing for control of pathogens in pepperoni were investigated. Treatments consisted of irradiation doses of 1.25 kGy or 3.0 kGy, a heat treatment, and a control without heat or irradiation. Results showed that irradiating meat prior to production of dry, fermented sausage such as pepperoni, can yield pro ducts with quality indicators closely resembling those of traditional dry sausage, while still providing the required 5-log reduction of E. coli O157:H7.

Patties were made from pork loin, individually vacuum- or aerobic-packaged and stored either at 4 or -40°C. Refrigerated patties were irradiated at 0, 1.5, 3.0 or 4.5 kGy absorbed dose, and frozen ones were irradiated at 0, 2.5, 5.0, or 7.5 kGy. Samples were analyzed for lipid oxidation, volatile production and odor characteristics. Refrigerated samples were analyzed at 0, 1 and 2 weeks, and frozen ones after 0, 1.5 and 3 months of storage. With vacuum packaging, the lipid oxidation (TBARS) of both refrigerated and frozen patties was not influenced by irradiation and storage time except for the patties irradiated and refrigerated at 7.5 kGy. With refrigerated storage, panelists could detect irradiation odor at day 0, but not after 1 week at 4°C. With frozen storage, however, irradiation odor was detected even after 3 months of storage. With aerobic packaging, the TBARS of refrigerated pork patties increased with storage time. The TBARS of pork patties increased as irradiation dose increased at day 0, but the effect disappeared after 1 week at 4°C. Nonirradiated patties were preferred to the irradiated ones at day 0 because of the significant irradiation odor in the irradiated ones, but the off-odor disappeared after 1 week at 4°C. With frozen storage, patties irradiated at 7.5 kGy had higher TBARS than those irradiated at lower doses. Nonirradiated patties had higher preference scores than the irradiated ones for 1.5 months in frozen storage. Sulfur-containing compounds were responsible for most of the irradiation off-odor, but these volatilized quickly during storage under aerobic conditions. Overall, vacuum packaging was better than aerobic packaging for irradiation and subsequent storage of meat because it minimized oxidative changes in patties and produced minimal amounts of volatile compounds that might be responsible for irradiation off-odor during storage.

Longissimus dorsi muscle strips, approximately 20 mm long, 40 mm wide, and 5 mm thick (4 g), of pig were randomly placed in a single layer into labeled bags (four strips per bag) and packaged either aerobically or under vacuum. Samples in the bags were irradiated at 0, 5, or 10 kGy and stored at 4°C for 5 days. Lipid oxidation, the amount and identity of volatile components and sensory characteristics of raw pork strips were determined at 0 and 5 days of storage. Irradiated muscle strips produced more 2-thiobarbituric acid reactive substances (TBARS) than nonirradiated only in aerobic packaging during storage. Irradiation had no effect on the production of volatiles related to lipid oxidation, but produced a few sulfur-containing compounds not found in nonirradiated meat. This indicates that the major contributor of off-odor in irradiated meat is not lipid oxidation, but radiolytic breakdown of sulfur-containing amino acids. Many of the irradiation-dependent volatiles reduced to 50 to 25% levels during the 5-days storage under aerobic conditions. Irradiated muscle strips produced stronger irradiation odor than nonirradiated, but no irradiation dose or storage effect was found. Irradiation had no negative effect on the acceptance of meat, and approximately 70% of sensory panels characterized irradiation odor as barbecued-corn-like odor.

Irradiation dose affected production of volatiles in vacuum- and aerobic-packaged cooked pork sausage, but its effect on TBARS was minor. Storage increased production of volatiles and changed their composition only in aerobic-pack aged sausage. Among volatile components, 1-heptene and 1-nonene were influenced most by irradiation dose, and aldehydes by packaging type, TBARS and volatiles of vacuum-packaged irradiated cooked sausage did not correlate well, However, TBARS had very high correlation with amount of aldehydes, total volatiles, ketones and alcohols with long retention times in aerobic-packaged pork sausage. Heptene and 1-nonene could be indicators for irradiation; and propanal, pentanal, and hexanal for oxygen-dependent changes of cooked meat.

ABSTRACTEffects of purge temperature and sample holding time on volatile profiles were determined using a purge‐and‐trap/gas chromatography unit with autosampler. Purge temperature and sample holding time before purge influenced the profile of volatiles in raw and cooked meat. The most notable changes were observed when the purge temperature was increased from 60°C to 80°C. Many of the changes in volatiles were related to oxidation of lipids. We recommend that meat should be purged at 40°C or 50°C (temperature at sensory analysis) to minimize heat‐induced production of volatiles and sample purge should be done within 3h after sampling to reduce oxidative changes during sample holding time.

ABSTRACTColor changes in irradiated meat were species‐dependent. Irradiated pork and beef became less red as a result of irradiation and display time. The redness values of turkey increased after irradiation but decreased during display time. The yellowness of the irradiated samples, for all species, increased as a result of irradiation and display. Visual evaluation of irradiated pork and beef indicated an increase in brownness, whereas turkey increased in redness as dose increased. The surface color of irradiated pork became less uniform than unirradiated pork. Reflectance spectra indicated that irradiation induced a metmyoglobin‐like pigment in pork and beef, whereas the pigment in turkey was unchanged.

The optimal conditions of pressure, time, and processing temperature required to eliminate Listeria monocytogenes Scott A and Salmonella typhimurium ATCC 13311 in fresh pork loin and the effect of these optimal conditions on quality and shelf life were determined. Twenty-five grams of fresh pork loin were inoculated with either of the two organisms and were subjected to pressures between 414 and 827 MPa at either 2 or 25 degrees C for 30 min. The D414MPa(25 degrees C) was determined to be 2.17 min for L. monocytogenes and the D414 MPa (2 degrees C) was determined to be 1.48 min for S. typhimurium. Samples subjected to a 6D process were evaluated by sensory and objective tests as well as for shelf life. These samples were found to be different (P < 0.05) from controls when evaluated after cooking by a triangle test of difference, but only when the pressure was applied at 2 degrees C and not at 25 degrees C. The descriptive analysis test showed that cooked samples treated at 25 degrees C were not different (P > 0.05) from controls in flavor, juiciness, and firmness. Color, peak load, water-holding capacity, and moisture were not found to be different (P > 0.05) between samples treated at 25 degrees C and controls when both were cooked. However, in the raw state, differences were found in the values for color parameters L and b. The level of psychrotrophs was 5.7 log CFU/g for samples treated at 25 degrees C after 33 days of storage at 4 degrees C, as compared with 7.0 log CFU/g for controls. The color and peak load (texture) did not change over the storage period (P > 0.05) in any of the samples. All samples spoiled in 5 days when stored at 25 degrees C.

During the reflight of the tethered satellite system, the electron generator assembly (EGA) emitted steady electron beams six times with the satellite deployed between 6.2 and 16.1 km. Maximum beam energies and currents were 1.65 keV and 0.4 A, respectively. Data presented here show that: (1) emissions create local electron clouds that can charge the shuttle, (2) ionization of thruster gas by beam electrons in the sheath did not reduce the shuttle potential, (3) the EGA utilizes more than half the induced potential, and (4) ionospheric density gradients and magnetic field orientations affect the circuit's potential distribution.

Effects of packaging and irradiation combinations on lipid oxidation, off-flavor, and color changes of raw patties prepared from three pork muscles were studied. Patties were prepared from each of the ground L. dorsi (L. thoracis and lumborum), psoas, and R. femoris muscles of pig, packaged either in oxygen permeable polyethylene bags or impermeable nylon/polyethylene bags, irradiated with an electron beam at 0 or 4.5 kGy dose, and then stored up to two weeks at 4 °C. Lipid 8 oxidation and color of the patties were determined after 0, 3, 7, and 14 days of storage, and volatiles 24 hr after irradiation. Irradiation and high fat content accelerated the lipid oxidation in raw meat during storage. Oxygen availability during storage, however, was more important than irradiation on the lipid oxidation and color values of raw patties. Irradiated meat produced more volatiles than nonirradiated patties, and the proportion of volatiles varied by the packaging-irradiation conditions of patties. Irradiation produced many unidentified volatiles that could be responsible for the off-odor in irradiated raw meat. No single volatile components but total volatiles, however, could be used to predict lipid oxidation status of raw meat.

Changes in color of irradiated meat were observed to be species-dependent. Irradiated pork and turkey became redder due to irradiation but irradiated beef a* values decreased and yellowness increased with dose and storage time. The extent of color change was irradiation dose-dependent and was not related to myoglobin concentration. Visual evaluation indicated pork and turkey increased in redness whereas beef decreased in redness as dose levels increased. Reflectance spectra showed that irradiation induced an oxymyoglobin-like pigment in pork and that both oxymyoglobin and metmyoglobin developed in beef as a result of irradiation.

We present environmental responses observed by the Shuttle Potential and Return Electron Experiment during 13 prolonged electron beam emissions from the Fast Pulsed Electron Generator (FPEG) during the TSS 1R deployment. As the tether lengthened from 0.18 to 2.5 km, FPEG fired nine times at a nominal current of 100 mA at 1 keV. The motional potential induced across the system increased from 24 to 225 V. With a 15 Ω resistor connecting the tether to shuttle ground, current was higher and the degree of negative shuttle charging lower when FPEG was off than when it was on. While most FPEG firings left the shuttle uncharged, two created significant potentials: one to +70 V in a nighttime, equatorial plasma depletion and one to ‐60 V, with the tether ∼ 15 km.