Effects of Low-dose Electron Beam Irradiation on Respiration, Microbiology, Texture, Color, and Sensory Characteristics of Fresh-cut Cantaloupe Stored in Modified-atmosphere Packages

Fresh‐cut cantaloupe was placed in modified‐atmosphere packages (4% oxygen, 10% carbon dioxide) and irradiated at 0 (control), 0.5, and 1.0 kGy. Irradiated samples had a lower and more stable rate of respiration than non‐irradiated samples over about 20 d. Total plate counts were higher (P < 0.05) in non‐irradiated control samples through day 11 (Trial 1) and for all dates tested (Trial 2). Color and texture remained stable for the duration of each study as measured by instruments and trained sensory panels. Sensory evaluation rated the 1.0‐kGy sample highest in “sweetness” and “cantaloupe flavor intensity” and lowest in “off‐flavor” after 17 (±3) d of storage. Low‐dose electron beam irradiation of fresh‐cut cantaloupe with modified‐atmosphere packaging offers promise as a method of extending shelf life.     

MR relaxation times in human brain: measurement at 4 T

PURPOSE: To determine the values for relaxation times in human brain for magnetic resonance (MR) imaging at 4 T. MATERIALS AND METHODS: T1 measurements were made with a progressive saturation sequence, an implementation of the Look-Locker sequence, and an inversion-recovery (IR) interleaved echo-planar imaging (IEPI) sequence. T2 measurements were made with a standard spin-echo (SE) sequence and an SE IEPI sequence. RESULTS: The T1 measurements yielded values of 1,724 msec +/- 51 for gray matter, 1,043 msec +/- 27 for white matter, and 4,550 msec +/- 800 msec for cerebrospinal fluid. The deep gray matter regions had T1 values of 1,458 +/- 38 (caudate nucleus) and 1,372 +/- 60 (putamen). The T2 measurements yielded results of 63 msec +/- 6.2 for gray matter and 49.8 msec +/- 2.2 for white matter. CONCLUSION: The T1 values measured at 4 T show a higher value than predicted from extrapolation at lower field strengths. The T2 measurements showed a slight decrease in values over those measured at lower-field strength. The gain in signal-to-noise ratio from the higher field strength may be substantially offset by these altered relaxation time values to a degree that is sequence dependent.     

Isolation and properties of extracellular alkaline phosphatase from Bacillus intermedius

Patients with chronic disease may be excluded from capitated managed care plans due to higher than average expected costs. In an attempt to remedy this inequity, one type of risk adjustment technique proposes to set separate capitation rates for certain chronic illnesses, including coronary artery disease (CAD). Cardiologists, who increasingly are requested to accept capitation, will benefit from understanding the impact of using clinical factors as opposed to using demographic factors to set capitation rates. Using a 5% national random sample of the 1992 Medicare population, we determined mean annual expenditures and variation in expenditures of individuals with CAD. We compared the use of 2 demographic factors currently used for capitation rate adjustment (age and gender) with 2 factors not currently used--3-digit International Classification of Disease (ICD-9) code (a measure for severity) and Charlson index (a measure for comorbidity). Mean annual expenditures for individuals with CAD were more than double mean annual expenditures for the general Medicare population ($6,944 vs $3,247). Among individuals with CAD, mean expenditures of subgroups defined by both age and gender ranged from $6,205 to $7,724. In comparison, stratifying by measures of severity and comorbidity identified subgroups with lower and higher mean expenditures, producing a range of $1,702 to $19,959. Substantial variation of expenditures for individuals within subgroups defined by severity and comorbidity remained, with few patients having substantially higher expenditures than the rest. When capitation rates are set with the use of demographic factors alone, patients may be subjected to risk selection and physicians to financial loss. Using clinical measures may decrease the incentive for patient risk selection, but substantial financial risk to physicians would remain, because of a relatively few patients with high expenditures (or costs).     

Staphylococcal enterotoxins

Staphylococcus aureus is a major human pathogen that produces a wide array of toxins, thus causing various types of disease symptoms. Staphylococcal enterotoxins (SEs), a family of nine major serological types of heat stable enterotoxins, are a leading cause of gastroenteritis resulting from consumption of contaminated food. In addition, SEs are powerful superantigens that stimulate non-specific T-cell proliferation. SEs share close phylogenetic relationships, with similar structures and activities. Here we review the structure and function of each known enterotoxin.     

Method to Measure the Force to Pull and to Break Pin Bones of Fish

A texture measurement device was modified to measure the force required to pull pin bones from King salmon (Oncorhynchus tshawytscha), snapper (Pagrus auratus), and kahawai (Arripis trutta). Pulled bones were also subjected to tension to measure the breaking force. For all fish, the pulling force depended on the size of the fish, and on the length of the pin bone (P < 0.05). In general, larger fish required greater pulling force to remove pin bones. For example, fresh small salmon (about 1500 g whole) required 600 g on average to pull pin bones, and large fish (about 3700 g whole) required 850 g. Longer bones required greater pulling force. The breaking force followed the same trend. In general, the breaking force was greater than the pulling force. This allows the removal of the bones without breaking them. There was no statistically significant (P > 0.05) difference between the forces (both pulling and breaking) from fresh and frozen/thawed samples, although in general frozen/thawed samples required less force to pull. With the quantification of pulling and breaking forces for pin bones, it is possible to design and build better, “more intelligent” pin bone removal equipment.     

The effect of mincing method on the quality of refrigerated whiting burgers

Different mincing methods in the preparation of refrigerated whiting burgers had a significant effect on the products' quality during storage ( P  < 0.05). The burgers containing pre-cooked mince products (PCMP) had the lowest microbial load with longest sensory shelf life (10 days). Oven drying of dry ingredients with subsequent hygienic practices markedly decreased microbial load in final products, from 5.30 to <1.47 log CFU g⁻¹ for PCMP, 5.80–2.45 log CFU g⁻¹ for washed mince products (WMP), 5.65–2.14 log CFU g⁻¹ for unwashed mince products. The lowest trimethylamine and total volatile basic nitrogen (TVB-N) were observed with WMP reaching 14.7 and 42.03 mg per 100 g, respectively, at the end of storage. The differences in average surface colours of samples with different preparations and different additives were significant after mincing, but decreased after addition of ingredients, and after cooking. This study indicates the possibility of using pre-cooking as a method for formulated fish mince-based products as it had the highest consumer acceptance as well as longer sensory shelf life despite its higher values of trimethylamine and TVB-N compared with WMP.     

Measurement of High‐Pressure Carbon Dioxide Solubility in Orange Juice,Apple Juice,and Model Liquid Foods

ABSTRACT: An experimental system to measure the carbon dioxide (CO₂) solubility in liquids at different pressures was designed and tested. Pressure and temperature were controlled in the system, and the design assured an accurate measurement of solubility. Experimental measurements of CO₂ solubility were performed in pure water, model solutions (ascorbic acid–sugars–water, citric acid–sugars–water), and in commercial orange juice (OJ) and apple juice (AJ), as a function of pressure (7.58 to 15.86 MPa) at constant temperature (40 °C). Aspen simulation software was used to predict the solubility in simple cases. All experimental results and predictions from simulations were compared with literature data. Measurements of CO₂ solubility in pure water were not significantly different than the literature. CO₂ solubility (g/100 g of liquid) results in the model liquids and in the juices were lower than for pure water, due to the presence of solutes. The software simulation was able to predict the CO₂ solubility in the model systems at low pressures.     

Radiofrequency shielding of surface coils at 4.0 T

Because radiation loss associated with a radiofrequency (RF) coil increases as roughly the fourth power of the frequency, this loss mechanism may become important in high-field studies above 2.0 T. In this study, the contribution of radiation losses at 4.0 T were determined in a rectangular surface coil using an RF shield to modify the radiation losses. The effect of this shield was determined on coil Q, B1 distribution, and signal to noise as a function of distance between the coil and the shield. Phantoms and human tissue were evaluated to characterize the loss mechanisms. The results demonstrate a large radiation loss in the unshielded surface coil. However, the radiation losses in vivo were not dominant owing to a large inductive loss occurring from dielectric currents in the body at 170 MHz.     

Microbial and Sensory Assessment of Milk with an Electronic Nose

ABSTRACT: An electronic nose (e-nose) was used to assess milk odor inoculated with Pseudomonas fluorescens or Bacillus coagulans , and odors were correlated with microbial loads and sensory scores. Sterile whole, reduced-fat, and fat-free milk were inoculated, stored at 1.7, 7.2, and 12.8 °C, and evaluated at d 0, 3, 5, 7, and 10 by e-nose and sensory panel. Aerobic plate counts were performed. E-nose readings, microbial counts, and sensory data were analyzed using discriminant function analysis. The e-nose discriminated differences in odor due to microbial load and sensory data. This may lead to a rapid method for determining sensory evaluation and microbial loads of milk.