Jose Manuel Bruno Barcena M Andrea Azcarate Peril and Faustino Sineriz

During the last few years we have seen a public debate, involving every social statement, concerning food products and ingredients (1). The appearance in the market of the first food products, or organisms, which have been improved by recombinant DNA technologies (rDNA), has been received by society in a negative manner. We are referring specifically to genetically modified (GM) food products. Several definitions can explain the concept of GM products or, in a general way, the imprecise word...

Coliforms

Add 225 mL peptone water to 25 g of the sample. Shake during 1-2 min. The final suspension is a 1 10 dilution of the sample. 2. Prepare 9 sterile test tubes containing 9 mL each one of BGBL medium and the inverted fermentation tubes (see BGBL culture medium, Subheading 2.4., item 4). 3. Add with sterile pipet 1 mL of the 1 10 dilution of the sample to each of three of the test tubes mentioned earlier. The suspension obtained will be a 1 100 dilution of the original sample. Follow the same...

Total Nitrogen

Nitrogen compounds in grapes play important roles as nutrients for microorganisms involved in winemaking and wine spoilage and as aroma and aroma precursors (7). Nitrogen is taken up by the vine roots as nitrate and reduced by the nitrate reductases system to ammonia, transported and stored subsequently as amino acids (7). Compared with fermentable carbon generally present in grapes at > 20 (w v), total nitrogen levels range from 0.006 to 0.24 , of which only 0.0021-0.08 is biologically...

References On Food Microbiology

Giannessi, P., and Matta, M. (1978) Azoto amminico, in Trattato di Scienza e Technica Enologica, Vol. I. (Brescia, A. E. B., ed.) Analisi e Controllo dei mosti e dei Vini, Italy, pp. 87-88. 2. Henick-Kling, T., Edinger, W. D., and Larsson-Kovach, I.-M. (1996) Survey of available nitrogen for yeast growth in New York grape musts. Wein-Wissenschaft 51(3), 169-174. 3. Rapp, A., and Reuther, K. H. (1971) Der Gehalt von Aminosauren in gesunden und edelfaulen Beeren verschiedener Rebsorten. Vitis 10,...

PH Cascade Controller Design

System Analysis Using the Simulation Model A cascade controller of pH coupled with DO control developed here is shown in Fig. 3. Proportional and integral PI , and proportional, integral, and differential PID controllers were used as precompensators of DO and pH in the cascade controller, respectively. The dynamic response of boxes A and B can be analyzed using the simulation model. The analysis is useful for design of the controllers, especially selection of controllers and...