[Percutaneous drainage of pyogenic hepatic abscesses]. / Drenaje percutáneo de abscesos hepáticos piogenos.

Thirty-five patients with pyogenic hepatic abscesses who underwent percutaneous drainage techniques are analyzed in a study period that comprises six years (from 1986 to 1992). Of the 35 cases, 7 (20%) presented abscesses smaller than 5 cm and were drained by puncture aspiration only. All of them were cured. One or more pig-tail 8 F catheters were placed in the remaining 28 patients (80%). The cure rate was 78.5%. The average drainage period comprised 15 days. Fourteen patients (40%) presented lesser complications during either the procedure in itself or the convalescence period, bacteriemia being the most frequent one. The mortality rate was 17%.

Drenaje percutáneo de abscesos hepáticos piogenos. / [Percutaneous drainage of pyogenic hepatic abscesses]

Thirty-five patients with pyogenic hepatic abscesses who underwent percutaneous drainage techniques are analyzed in a study period that comprises six years (from 1986 to 1992). Of the 35 cases, 7 (20

) presented abscesses smaller than 5 cm and were drained by puncture aspiration only. All of them were cured. One or more pig-tail 8 F catheters were placed in the remaining 28 patients (80

). The cure rate was 78.5

. The average drainage period comprised 15 days. Fourteen patients (40

) presented lesser complications during either the procedure in itself or the convalescence period, bacteriemia being the most frequent one. The mortality rate was 17

.

[Thermal resistance of Candida tropicalis and Rhodotorula rubra in orange juice]. / Resistenica térmica de Candida tro picalis y Rhodotorula rubra en jugo de naranja.

The thermal resistance of two yeasts (Candida tropicalis and Rhodotorula rubra) was studied. The yeasts were isolated from Venezuelan pasteurized orange juice obtained at retail level. The flask method was utilized, applying temperatures which ranged from 49.5 to 53.5 degrees C to initial populations of 1x10(5) cells/ml of orange juice. Values of D50C=3.4 min and z=4.1 degrees C were found for C. tropicalis, and D50C=2.6 min and z=9.8 degrees C for R. rubra. Linear correlation coefficients of r=0.99 and r=0.98 wee obtained, respectively, for the experimental data.

[Optimization of the freezing process by load]. / Optimización de procesos de congelación pro cargas.

A model was developed for the optimization of batch freezing to maximize the daily production of a plate freezer. An equation for the prediction of the optimal product thickness was found. The model was evaluated experimentally in a one-plate freezer with a food model consisting of a 9% bentonite mixture. The model demonstrated it predicted adequately the freezing times and optimal product thickness. Under the experimental conditions used by the authors, an optimal thickness of 0.0142 m was found, with five batches per day. The maximum daily production was 3.152 kg.

[Effect of the position of the container in the retention of nutrients in food models heated by natural convection]. / Efecto de la posicíon del envase en la retención de nutrientes en modelos alimentarios calentados por convección natural.

The existence of statistically significant differences in the nutrient retention of products heated by natural convection in cylindrical containers of equal size when thermally processed in vertical and horizontal position was studied. The thiamine retention was found to be significantly greater for containers placed in vertical position. A modification to the model proposed by Barreiro (4) for the prediction of nutrient retention during thermal processing of vertically placed canned model systems heated by natural convection was also developed to adapt it to containers processed in a horizontal position. To achieve this goal, an equivalent characteristic length was found for the vertically placed containers, and several changes were introduced. The modified model was then evaluated through ten experiments with different thermal processing parameters. The theoretical thiamine retention values predicted by the model wee compared with the experimental retention. In all cases they were within the 99% confidence interval of the experimental values. This demonstrated that the modified model can accurately predict nutrient retention during thermal processing of products packed in cylindrical containers, and placed in horizontal position.

Resistencia termica de Candida tropicalis y Rhodotorula rubra en jugo de naranja. / Thermal resistance of Candida tropicalis and Rhodotorula rubra in orange juice

El presente trabajo constituye un estudio sobre la resistencia termica de dos levaduras (Candida tropicalis y Rhodotorula rubra) que frecuentemente se aislan de muestras de jugo de naranja pasteurizados comerciales, recolectadas en el mercado venezolano. El experimento se desarrollo siguiendo el metodo del frasco, y aplicando temperaturas comprendidas entre 49.5 y 53.5 grados C, a poblaciones iniciales de 1 x 10 a quinta celulas/ml de jugo. Se encontraron valores de D50C = 3.4 min y z = 4.1 grados C para C. tropicalis y de D50C = 2.6 min y z = 9.8 grados C para R.rubra, obteniendose coeficientes de correlacion lineal r = 0.99 yr = 0.98, respectivamente, para los datos experimentales

Optimizacion de processos de congelacion por cargas / Optimization of the freezer processes by loads

Se desarrollo un modelo para la optimizacion del proceso de congelacion con miras a maximizar la produccion diaria de un congelador de platos, proceso que culmino con una ecuacion para predecir el espesor optimo del producto a congelar. El modelo se comprobo experimentalmente en un congelador de un plato, con un modelo alimentario consistente en una mezcla de bentonita al 9%.Se demostro que el modelo desarrollado predice satisfactoriamente los tiempos de congelacion y el espesor optimo del producto. Asimismo, bajo las condiciones en que se llevo a cabo el experimento, se constato un espesor optimo de 0.0142m, con el cual era factible obtner en cinco cargas el dia una produccion diaria maxima de 3152 Kg