EFFECT OF RAPID COOLING OF SHELL EGGS ON MICROCRACK DEVELOPMENT, PENETRATION OF SALMONELLA ENTERITIDIS, AND EGGSHELL STRENGTH

Eggs were subjected to cryogenic cooling treatments using liquid CO₂ or liquid N_2. In order to minimize the thermal stress in eggshells due to rapid cooling, a two-stage air-cooling method was also evaluated in this study. Eggs were cooled from an initial temperature of 25C to approximately 7C. It was found that cooling produced microcracks on eggshells. However, rapid cooling did not increase the penetration of Salmonella enterica serovar Enteritidis (Salmonella enteritidis) into egg contents. When egg contents alone were sampled for Salmonella enteritidis, extending the immersion time from 24 to 48 h significantly (P < 0.01) increased the penetration of Salmonella enteritidis from 5.0 to 25.0%. When egg contents together with eggshells were sampled, Salmonella enteritidis was detected in 100% of the egg samples at the above two time intervals. There were no significant differences (P > 0.05) in the eggshell strength between control (no cooling) and cooling treatments, indicating that cooling did not weaken eggshell strength.     

Modelling Musical Perception: A Critical View

This is a study of two attempts to develop quantitative models of timing in music performance, one based on connectionism and the other involving the autocorrelation function. The former is concerned with the ‘quantization problem’ of interpreting durations of time from a musical performance as note shapes which represent duration in music notation. The latter is an attempt to represent what makes such performances ‘‘expressive ’. These models were derived by Peter Desain, but there is a paucity of validating data in the published literature. Attempts to collect additional data have revealed significant shortcomings in both models, as well as methodological flaws. The most important problem is that the attempt to solve the quantization problem lacks any representation of high-level structure. As a result, if the music itself tends to be based on relatively irregular rhythmic patterns, the connectionist model can distort even a metronome-perfect performance, rather than recognizing the correct temporal patterns. Attempts are made to explain how these shortcomings may have arisen.     

Stability of Mackerel Surimi Prepared under Lipid-Stabilizing Processing Conditions

Surimi from mackerel whole and light muscle was prepared under conditions designed to minimize oxidation and development of rancidity. The lipid-stabilizing procedure included early addition of both lipid-and water-soluble antioxidants, avoidance of added sodium chloride, and exclusion of oxygen. Surimi prepared from light muscle was stable to rancid odor development in both the raw and cooked form; gel strength was reasonably stable during frozen storage, although the color was somewhat dark. Surimi prepared from mackerel whole muscle was darker, its odor quality lower and less consistent, and its gel strength lessened more rapidly during frozen storage than surimi prepared from light muscle.     

In-line viscometry in the dairy processing industry

The viscosity of a fluid, or fluid like material, is a measure of its resistance to flow. Many foods are fluid in nature, as final products and/or during production. The viscosity of the final product is an indicator of product consistency and can determine consumer preferences. During production a suitable and reliable in-line viscometer can help monitor the process, optimize yield, increase efficiency, reduce costs, enable a degree of automated control and improve final product consistency and quality. Whether such goals can be achieved in practice depends on many factors. This paper gives an overview of these factors.     

MULTIELEMENT ANALYSIS OF FOODS STORED IN THEIR OPENED CANS1

A multielement analysis of canned foods was performed on foods stored in their opened containers. Canned fruits and fruit juices were sampled upon initial opening as well as two and five days after opening. After mineralization, the samples were analyzed for 25 elements using an inductively coupled argon plasma. The following elements were quantitated: Al, Ca, Cu, Fe, Mg, Mn, Ni, P, Sn, Ti, and Zn. The concentration of Fe and Sn increased between successive sampling days. These increases did not exceed permissible limits of Sn in canned foods and the Fe concentrations may be of nutritional interest. A decrease in the concentration of P between successive sampling days was associated with insoluble material formation. Scanning electron microscope micrographs coupled with X-ray fluorescence analysis of the can interior surfaces were used to characterize the corrosion of the interior surface of the cans.     

Interaction of ultraviolet light, chemicals and cultured mammalian cells: photobiological reactions of halogenated antiseptics, drugs and dyes

We have successfully demonstrated that cells in culture are sensitive to damage produced by a variety of phototoxic agents. Differences in the apparent sensitivity of the three cell systems employed (photohaemolysis, phototoxicity to macrophages and to Chinese hamster CHV79 cells) have been exploited to reflect the mechanism of action of the phototoxic materials. Overall four distinct patterns of phototoxic response were observed which indicate specific sites of action of the phototoxic materials within the cell. Of the two halogenated antiseptics tested 3,3',4',5-tetrachlorosalicylanilide (T₄CS) was phototoxic and 3,4,4'-trichlorocarbanilide (TCC) was not; of the drugs both 8-methoxypsoralen (8-MOP) and chlorpromazine (CP) were phototoxic; and of the three dyes rose bengal (RB) and Blankophor (FB) were phototoxic and Tinapol (EMS) was not. Phototoxic cellular damage produced by CP, RB and FB could be totally prevented by continuous gassing with O₂-free, 5% CO₂ in N₂. T₄CS and 8-MOP phototoxic cellular damage was found to proceed independently of the presence or absence of O₂.     

Source Allocation of Aliphatic and Polycyclic Aromatic Hydrocarbons in Particulate-Phase (PM10) in the City of Valdivia,Chile

The concentration and signature of n-alkanes (n-C₁₀ to n-C₃₃) and 18 PAHs were determined in air filters across a year period (2010) in an urban area of the city of Valdivia, Chile. Filter samples were extracted using sohxlet apparatus and analyzed by GC-MS techniques. Concentrations of total hydrocarbons ranged from 45–352 ng.m^?3 and total PAHs ranged from 2.93–78.01 ng.m^?3. Concentrations of hydrocarbons during the summer were high (288–352 ng.m^-3) and reduced when the autumn began (45–79 ng.m^?3) to then increase almost linearly to the next summer. The drop in concentration was attributed in part to the significant reduction of traffic when summer ends as tourists leave the city (about 9–15% of the total cars circulating). Results from the chemometric technique of Polytopic Vector Analysis (PVA) indicated three main sources for the alkanes: biogenic (terrestrial plants), signatures of oil combustion, and an unconfirmed source which is thought to come from non specific organic matter degradation. Total PAHs correlated well with total particulate matter with a R² = 0.94. Levels of PAHs in the atmosphere were higher during the winter (6.85–78.01 ng.m^?3) period than the rest of the year (2.93–36.30 ng.m^?3). PVA results indicate three key sources of PAHs and two of those sources derived from oil combustion and biomass burning.     

INSTANTANEOUS VELOCITY PROFILE MEASUREMENTS IN A TURBULENT BOUNDARY LAYER

Instantaneous wall shear stress and streamwise velocities have been measured simultaneously in a flat-plate, turbulent boundary layer at moderate Reynolds number in an effort to provide experimental support for large eddy simulations. Data were obtained using a buried-wire, wall shear gage and a hot-wire rake positioned in the log region of the flow. Fluctuations of the instantaneous U ⁺ versus Y ⁺ profiles about a mean law of the wall are shown to be significant and complex. Peak cross-correlation values between wall shear stress and the velocities are high, and reflect the passage of a large structure inclined at a small angle to the wall. Estimates of this angle are consistent with those made by other investigators. Conditional sampling techniques were used to detect the passage of various sizes and types of flow disturbances (events), and to estimate their mean frequency of occurrence. Events characterized by large and sudden streamwise accelerations were found to be highly coherent throughout the log region and were strongly correlated with large fluctuations in wall shear stress. Phase randomness between the near-wall quantities and the outer velocities was small. The results suggest that the flow events detected by conditional sampling applied to velocities in the log region may be related to the bursting process.     

An algorithm for optimal buffer placement in reliable serial lines

The optima] allocation of buffer capacity in unbalanced production lines with reliable but variable workstations is a complex and little-researched topic. Analytic formulas for the throughput of these lines do not exist, so simulation is the only practical alternative for estimating throughput. Exhaustive search over all possible buffer allocations quickly becomes impractical beyond short lines and few buffers. Thus an algorithm is needed to efficiently find optimal or near-optimal allocations. We develop a simple search algorithm for determining the optimal allocation of a fixed amount of buffer capacity in an n-station serial line. The algorithm, which is an adaptation of the Spendley-Hext and Nelder-Mead simplex search algorithms, uses simulation to estimate throughput for every allocation considered. An important feature of the algorithm is that the simulation run length is adjusted during the running of the algorithm to save simulation run time when high precision in throughput estimates is not needed, and 10 ensure adequate precision when it is needed. We describe the algorithm and show that it can reliably find the known optimal allocation in balanced lines. Then we test the ability of the algorithm to find optimal allocations in unbalanced lines, first for cases in which the optimal allocation is known, and subsequently for cases in which the optimal allocation is not known. We focus particularly on lines with multiple imbalances in means and variances. In general, our algorithm proves highly efficient in finding a near-optimal allocation with short simulation run times. It also usually finds the true optimal allocation, but it is in the nature of this problem that many buffer allocations differ in throughput by small amounts that are difficult to resolve even with long simulation runs.