Evaluation of strategies for reducing patulin contamination of apple juice using a farm to fork risk assessment model

The numerous studies conducted so far on the issue of patulin contamination have focused mainly on aspects like growth of Penicillium expansum, patulin production under different conditions and the influence of processing on the patulin concentration in apple juice. The purpose of the present study was to collect the necessary information and to develop a quantitative risk assessment model (QRAM) in order to evaluate different strategies to reduce patulin contamination. For apple juice (AJ) production 3 types of apples are considered, namely fresh apples, apples stored under cold air (short term storage) and apples stored under controlled atmosphere (CA) (long term storage). The QRAM described the complete chain from the picking of apples until storage of produced AJ. In comparison to a traditional chemical analysis, the QRAM was found accurate in predicting the concentration of patulin in cloudy and clear AJs commercialised in Belgium. Simulation of the model demonstrated that the use of apples stored under CA contributes to a large extent to the patulin contamination of AJ. Since apples stored in CA are used from more or less January onwards, AJ with high patulin concentration can be produced from January onwards. It would be useful in this respect to take this into account when sampling plans are made by apple juice producers in the framework of their HACCP-system and by governments and control agencies when monitoring programmes are elaborated. The duration of deck storage between the delivery at the apple juice producer (AJP) and the processing of the apples had a large influence on the patulin concentration, and this effect was more pronounced for apples stored under controlled atmosphere compared to apples stored under cold air. The duration of the deck storage should therefore be considered as a Critical Control Point (CCP) within HACCP-systems. Also the application of a sorting step was evaluated to be efficient to reduce the high patulin concentration in AJ. Therefore, a combination of the 2 most effective measures (namely sorting out apples with an infection lesion larger than 10 cm(2) and a reduction of the volume of CA apples) was tested and resulted in a reduction to levels below 25 μg/kg in 99.7 to 99.9% of the clear and cloudy apple juices, respectively. It is therefore advisable to include a sorting step prior to processing, when apples stored in CA are used.     

Optimization of the column loadability for the preparative HPLC Separation of soybean phospholipids

A simple and rapid preparative-scale separation method was investigated in order to obtain pure soybean phospholipids. Because of technical and economical reasons, two coarse, irregular silica gels were selected. Comparing both stationary phases, a ternary mixture of hexane, 2-propanol and water yielded a different elution order of the phospholipids at analytical sample loads, in spite of the chemical similarity of these packing materials. During scaleup, it became obvious that the retention characteritics were largely influenced by the sample load, thus making the 15–35 μm RSiL inappropriate for preparative-scale separations of phospholipids. Moreover, the column loadability could be increased by controlling the flow rate. Hence, a solvent program was elaborated which enabled a column loadability of up to 2% by weight of the stationary phase. Using analytical high performance liquid chromatography, it was shown that the method proposed yielded over 90% pure phospholipids at a recovery of nearly 80%. Research assistant of the Belgian National Fund for Scientific Research (N.F.W.O.).     

MRI screening for acoustic neuroma without gadolinium: value of 3DFT-CISS sequence

To evaluate the efficacy of a gradient-echo sequence (3DFT-CISS) in the diagnosis of acoustic neuromas, two independent observers twice reviewed the images of the temporal bones of 83 patients. Contrast-enhanced T1-weighted spin echo images were used as the reference, showing 18 acoustic neuromas, including 5 purely intracanalicular and one intralabyrinthine tumours. High sensitivity (89-94%), specificity (94-97%) and accuracy (94-95%) were found. Intraobserver (kappa 0.93-1) and interobserver (kappa 0.83-0.84) reproducibility were very good. The smallest intracanalicular tumour was overlooked twice by both observers; the intralabyrinthine tumour once by one observer. All tumours were detected with a less stringent decision criterion, at the expense of lower specificity.     

Free-to-total prostate specific antigen ratio as a single test for detection of significant stage T1c prostate cancer

PURPOSE: We investigated whether impalpable, invisible (stage T1c) but significant prostate cancer can be detected better by determining the free-to-total prostate specific antigen (PSA) ratio of equivocal PSA serum levels. MATERIALS AND METHODS: The specificity of free-to-total PSA ratio using research monoclonal enzyme immunoassays was compared to that of PSA greater than 4.0 ng./ml. in 117 consecutive patients with PSA 3 to 15 ng./ml. (Hybritech Tandem-R assay) due to untreated benign prostatic hypertrophy or prostate cancer. Of the patients 77% underwent adenectomy or radical prostatectomy with thorough pathological evaluation of surgical specimens. RESULTS: Benign prostatic hypertrophy had a greater median free-to-total PSA ratio than stages T1c and T2 or greater prostate cancer (0.16 versus 0.09 and 0.11 ng./ml., p = 0.0001 and p = 0.0268, respectively). In stage T1c prostate cancer, areas under receiver operating characteristic curves were 0.58 and 0.84 for PSA and free-to-toal PSA ratio, and free-to-total PSA ratio correlated with prostate volume (r = 0.49, p = 0.005) and Gleason score (r = -0.37, p = 0.036). Pathologically, 84% of stage T1c cancers were significant and comparable to stage T2 or greater cancers. CONCLUSIONS: Free-to-total PSA ratio enhances the efficacy of PSA measurement by improving specificity for detecting impalpable, invisible but significant stage T1c prostate cancer.     

Effect of molecular and processing parameters on the flow-induced crystallization of poly-1-butene. Part 1: Kinetics and morphology

In this work the effect of molecular parameters (molecular weight (M_W), molecular weight distribution (MWD)) and processing conditions (crystallization temperature, flow conditions) on the isothermal crystallization behavior of three isotactic poly-1-butene (iPB) samples is investigated by means of rheo-optical techniques. The emphasis in this paper will be on the kinetics and the resulting morphology.Turbidity measurements show a strong effect of M_W and the degree of undercooling on the flow-induced crystallization (FIC), whereas the effect of MWD is not quite clear. Scaling relations, proposed in literature, that are based on polymer chain relaxation were found to predict correctly the dependence of FIC, at least when samples of similar MWD are considered. A mastercurve is presented combining effects of M_W, shear strain, shear rate and temperature.Optical microscopy observations provide information on the quiescent growth rate and the morphology of the crystallites. The effect of the different parameters on the observed transition from an isotropic morphology at low shear rates to a rod-like crystalline structure at high shear rates, could again be explained in terms of polymer chain relaxation.     

Application of microfocus X-ray radiography in materials and medical research

The advantages of real-time microfocus radiography are evaluated for several applications. These advantages are mainly the small focal spot size (5 μm) leading to a very low geometrical unsharpness (0.1 mm) for a magnification of 21 ×; the positioning of the specimen very close to the source (15 mm) leading to high magnifications (100 ×) and the minimal scattered radiation recorded on film. This radiographic technique was used to study the electrolytic codeposition of a Cu-layer on a metal substrate. Enlarged radiographic images of archaeological findings revealed the smallest detail. This helps in the restoration of pieces contaminated outside and remaining intact inside. For medical research microfocus X-ray radiography provided useful information on the reaction of bone tissue on specific osteoporosis medication, on the vascular changes in experimentally induced liver tumours and on the sequential deterioration of kidney stones.     

Reduction of radio-frequency interference of phase-controlled systems by load partitioning

It will be shown that a considerable amount of r.f.i.reduction in a phase-controlled system with a resistive load can be obtained if partitioning of the load resistor is possible.     

The new generation Siemens Multiline lithotripter tube "M": early results in ureteral calculi

The Siemens electromagnetic Lithostar tube "C" and the new multiline tube "M" lithotripters were compared for the in situ treatment of ureteral calculi. A series of 248 patients with a calcium oxalate ureteral stone (proven by stone analysis) more than 4 mm in diameter were treated between December 1994 and September 1995 with the tube M Multiline lithotripter. The results were compared with those of 462 patients treated in prior years with tube C. High energy levels were obtained without sedation in 11% of patients with tube C and in 61% with tube M. The proportion of patients needing additional analgetics was 11% and 6%, respectively. The percentages of patients reporting no pain at all were 7 and 77. In proximal calculi, stone-free status was achieved in 63 of 79 patients (80%) with tube C and in 82 of 91 patients (90%) with tube M (p = 0.057). In distal calculi, stone-free status was achieved in 124 of 173 patients (72%) with tube C and in 134 of 157 patients (85%) with tube M (p = 0.0027). The evacuation rate for distal ureteral stones was significantly higher with tube M, which implies that the new shock head can enable the operator to apply higher energy without sedation because of the better tolerance.