Bacteriological Safety of Swine Carcasses Treated with Reconditioned Water

Swine carcass microflora were evaluated for selected foodborne pathogens after exposure to reconditioned water during scalding, dehairing, and polishing operations. Reused water had been reconditioned and chlorinated. Rodac plates applied to hams were used to assess carcass microflora. Water samples were enumerated using membrane filtration or spiral plating. Sampling was at mid-week throughout the year. Total aerobic plate counts on hams were unaffected by treating with potable or reconditioned waters. No differences were observed for staphylococci, enterics, fecal streptococci, Listeria monocytogenes, coliforms, and Aeromonas levels. A preevisceration potable water carcass wash reduced the bacterial load, regardless of initial treatment. Bacterial counts on carcasses paralleled those in water. Reuse is an alternative to potable water for initial slaughter operations without diminishing bacteriologic safety.     

Climate change and viticulture: A European perspective on climatology, carbon dioxide and UV-B effects

Predicted changes in the climate of European viticultural regions over coming decades may alter significantly both the spectrum and the distribution of grape varieties currently used. Changes observed over recent years confirm those predictions. In particular, shifts in precipitation patterns will affect most European regions, with increased risk of drought, and given this scenario, the consequences would be most dramatic for the Iberian peninsula. Soil practices may have to be adapted to account for changes in soil moisture and decay rates of organic matter. Rising CO₂ concentration alone may increase grape production and water use efficiency, but more comprehensive studies predict decreases in yield when increasing temperature and changes in solar radiation are considered simultaneously. As part of those changes in solar radiation, levels of UV-B radiation will probably continue to rise, and will have a direct impact on grape composition and thus flavour development via alteration of secondary metabolites such as flavonoids, amino acids and carotenoids.     

Flame pyrolysis – a preparation route for ultrafine pure γ-Fe2O3 powders and the control of their particle size and properties

Highly dispersed γ-Fe2O3 powders with particle sizes down to 5 nm were directly synthesized by combustion of solutions of iron pentacarbonyl or iron(III) acetylacetonate in toluene in an oxyhydrogen flame. The particle size as well as other properties of the obtained powders can be controlled simply by varying the iron concentration in the starting solutions. Phase composition, morphological and magnetic properties of the powders were studied. The reasons for the formation of γ-Fe2O3 are discussed by means of structure–chemical/kinetic considerations. The materials are interesting as recording materials, or ferrofluids, or for colour imaging and bioprocessing. This revised version was published online in November 2006 with corrections to the Cover Date.     

FIELD PROCESSING OF TOMATOES 2. Product Quality and Composition

SUMMARY— Mechanically harvested tomatoes were macerated, heated by steam injection to several constant temperatures from 170–240°F and held in a treatment pot from 0-4.6 min at pH levels (adjusted with cont. HCI) ranging from natural down to pH 2.0. Treated macerates were neutralized to original pH with cone NaOH, put through a finisher screen and pumped through a deaerator and chiller. The optimum processing conditions based on highest consistency (efflux-pipet flow time) in seven series of samples were 212°F breaking temperature and a macerate treatment time of 3.3 min at pH 2.75. With the optimum conditions, juice solids yield from VF-145 tomatoes was 4.3% greater and consistency 90% higher than from the natural pH juice. The neutralized acid products could contain 13% less tomato solids and still have a consistency equal to that of the products extracted at natural pH. Dry waste decreased 33% and total wet waste 47%. A 1-day delay before processing caused 9.5% loss in recovered juice solids. Ascorbic acid, reflectance and lycopene data showed no trends due to acid extraction. Water soluble color increased slightly in the acid extractions.     

A SPACE–TIME FINITE ELEMENT MODEL TO STUDY THE INFLUENCE OF INTERFACIAL KINETICS AND DIFFUSION ON CRYSTALLIZATION KINETICS

We present a space–time finite element formulation to study the cooperative growth of adjacent needle-like crystals in a two-dimensional, binary melt. It is assumed that the system is isothermal and that the compositions of the melt and the crystals are different. The growth rate of the crystals is taken to be a function of the melt composition in front of the growing crystals, and the composition of the melt as a function of space and time is determined by the diffusion equation. The positions of the growth fronts of each crystal are tracked. Good agreement is found between the numerical solution of an approximated one-dimensional problem and an analytical solution. Numerical results of the simulation of the growth of isolated and adjacent crystals are presented. © 1997 John Wiley & Sons, Ltd.     

EFFECT OF WATER ACTIVITY ON THE GROWTH OF STAPHYLOCOCCUS AUREUS AT MEAT-CHEESE INTERFACES

There is increased marketing of ready-to-eat nonrefrigerated snack foods which consist of meat or sausage products with low or intermediate moisture levels combined with high moisture food products, i.e., cheese products. Packaging the intermediate moisture meat in direct contact with a high moisture food might change the water activity (a_w) of the products sufficiently to support growth of Staphylococcus aureus at contaminated interfaces. To evaluate this possibility, sterile sausage slices (a_w= 0.60 to 0.82) were surface inoculated with log 2-3 CFU/g of S. aureus, interfaced with processed cheese slices (a_w= 0.94), vacuum packaged, and incubated at 19, 28, 37C and at cyclic temperature of 19–37–19C. S. aureus levels and water activities were determined weekly for 0 to 9 weeks. The a_w at the interface changed rapidly and reached an a_w that supported S. aureus growth. Growth of S. aureus occurred under all test conditions when the samples were stored at 28 and 37C. At 19C storage S. aureus remained viable for the length of the study.     

Optical Absorption of the Transition Elements in Vitreous Silica

The optical absorption of 3d transition elements in fused silica was studied. A series of high-quality silica glasses doped with 0.01 to 0.1 wt% of each transition element (V through Cu) was prepared by a vapor hydrolysis technique. Their optical spectra were measured, and their practical absorptivities were calculated between 200 and 2000 nm. In the proposed waveguide use range (∼ 850 nm), V and Cr appear to absorb most (a_pract= 2.6 and 1.2 dB/km ppbw⁻¹ (metal), respectively) and Cu the least (a_pract≃0). Comparisons are made with data for conventional glasses.