EFFECT OF SODIUM LACTATE, CALCIUM LACTATE AND SODIUM ALGINATE ON BACTERIAL GROWTH AND AMINOPEPTIDASE ACTIVITY

The effects of sodium alginate (0.4 and 0.8%), calcium lactate (0.15 and 0.3%) and sodium lactate (60% solution; 1, 2, 3 and 4%) on growth and aminopeptidase activity of Pseudomonas fragi ATCC 4973 and Salmonella typhimurium in trypticase soy broth or autoclaved ground beef were studied for 5 days at 5°C. Sodium alginate and calcium lactate did not change colony counts of P. fragi or S. typhimurium; and had only slight effects on aminopeptidase activity. Sodium lactate (3 and 4%) showed inhibitory activity on growth and aminopeptidase activity of P. fragi. Sodium lactate also decreased aminopeptidase activity of S. typhimurium but had no major influence on colony counts. In general, aminopeptidase activity was inhibited more than cell multiplication by higher levels of alginate and sodium lactate .     

Optimal location of process measurements

The problem of optimally locating a given number of Bensors for observing a general linear distributed parameter system is considered. Measurements at the sensors are assumed to be available continuously in time, and the design criterion is minimization of a scalar measure of the covariance of the estimate error in the optimal linear filter. Necessary conditions for optimality are derived based on the formulation of a distributed parameter matrix minimum principle. A computational algorithm is developed for determining the optimum set of measurement locations. The algorithm is applied to the problem of optimally locating temperature sensors in a solid undergoing transient heat conduction.     

An assessment of OH airglow interference on the remote sensing of stratospheric HC1 via limb sounding in the near-I.R.

Chemiluminescent emission from the formation of vibrationally excited OH at an altitude of approximately 85 km presents a barrier to Earth limb measurements of near-infrared emissions originating in the stratosphere. High resolution measured spectra of OH airglow in the region of interest have not been reported, and thus it is difficult to assess its impact on moderately high resolution Earth limb spectroscopy capable of looking between strong OH lines. Low resolution rocket-borne spectrometer Earth limb measurements of OH airglow arc mathematically inverted to recover vibrational state populations that are used to simulate a higher resolution spectrum in the neighbourhood of 2843cm^-1, Implications for remote sensing HCI are presented.     

Hygroscopic Coatings Control Surface White Discoloration of Peeled (Minimally Processed) Carrots During Storage

White discoloration on peeled carrots is partially due to surface dehydration which can be controlled with hygroscopic coatings: e.g., polyhydric alcohols and salt solutions. This study was performed at 2.5, 7.5, 10, and 15°C, using a model system controlling relative humidity at 33, 75 or 98% or a commercial system with low-density polyethylene (LDPE) plastic film bags. The moisture sorption properties of propylene glycol, sorbitol, glycerol and calcium chloride enabled them to keep the carrot surface moist and maintain a transparent surface layer through which the underlying orange color was visible. This effect was only observed at high relative humidities (e.g., 98% RH). Similar effects were observed on treated peeled carrots stored in LDPE bags. The moisturized appearance provided by the hygroscopic coatings during storage was effective at several different temperatures.     

Optimization-based planning for the stochastic lot-scheduling problem

We describe a finite-horizon stochastic optimization model for the stochastic lot-scheduling problem and procedures for finding near-optimal solutions. Several different products are produced by a single-stage process with significant changeover times and costs, and the demand for these products is random. The deterministic version of this problem, the economic lot-scheduling problem, is the subject of a great deal of research. However, the problem with random demand for the products is commonly found in practice but is not as well researched. The models developed in this paper address the problem of dynamically planning the timing and size of production runs in this kind of production environment. We also report some computational results that indicate the quality of the resulting production schedules.     

INCIDENCE OF AFLATOXIGENIC ISOLATES OF ASPERGILLUS FLAVUS/PARASITICUS OBTAINED FROM GEORGIA CORN PROCESSING PLANTS

Two corn processing facilities within Georgia were evaluated in order to determine the incidence of Aspergillus flavus or A. parasiticus within the plant and in corn harvested and processed in 1984 and 1985. Conidia of A. flavus/parasiticus were found in all corn samples evaluated as well as in settled dust samples taken within these processing facilities. Isolates were obtained by using the differential/selective medium Aspergillus flavus/parasiticus agar. Upon subsequent culture only 55% of the selected isolates were confirmed as belonging to A. flavus/parasiticus group. Some of these isolates were randomly chosen and their ability to produce aflatoxins B₁, B₂, G₁, or G₂ evaluated. Thirty-two percent of the A. flavus/parasiticus isolates cultured for aflatoxin production were found to be aflatoxigenic.     

PATTERN RECOGNITION: PORTABLE COMPUTER PROGRAMS FOR THE FOOD INDUSTRY

Some of the available libraries of pattern recognition programs are tabulated. These include programs ARTHUR (University of Washington), RECOG (Lawrence Livermore Laboratory), and STAG (Fairfield University) the last of which uses both the APL and FORTRAN IV computer languages. The distinction between supervised and unsupervised methods of pattern recognition is presented and the more useful computer algorithms are described. These include programs and literature references for minimal spanning tree, factor analysis, linear dimension reduction, nonlinear dimension reduction, nearest neighbor, and the linear learning machine. The intent is to make the food process industry more aware of the availability of portable computer programs using that branch of artificial intelligence that has come to be termed pattern recognition.