Comparison of Rapid Methods for isolation and Enumeration of Clostridium perfringens in Meat

Three strains of Clostridium pefringens, ATCC 12924, ATCC 12917, and ATCC 14809, were inoculated separately into thioglycollate broth and ground beef samples and enumerated by Fung's Double Tube (FDT), Oxyrase Enzyme (OE), Gas Pak Anaerobic System (GPAS), and Anaerobic Petri Dish (APD) methods. Recovery of the three strains by FDT was significantly higher (P < 0.05) than that by the other three methods from both thioglycollate broth and ground beef, with OE second highest. FDT gave better recovery (84%) in less time (8–10 hr) at 42°C compared with the OE method (61%). FDT was also least costly.     

THE NEW PRIVATISM,FEDERALISM, AND THE FUTURE OF URBAN GOVERNANCE: NATIONAL URBAN POLICY IN THE 1980s

Two policies of the Reagan administration threaten the traditional role of cities both as basic elements in the nation's governing structure and as socio-economic communities. The long-standing belief that an important criterion for judging both public and private action is its contribution to the welfare of the city has been abandoned. Under what may be called the New Privatism the existence or creation of any community is now primarily justified by its capacity to serve the locational needs of private firms in a technology-driven national market. To continue Federal development aid to economically declining cities would contribute to inefficiency in the national spatial economy and cannot be justified. The Reagan version of the New Federalism calls for devolving greater power to the state and local levels. For cities, the opposite effect is more likely. The ending or reduction of most federal programs relating to cities and their residents has put many cities in a double bind. They must choose between using scarce local resources to compete with other communities to lure or hold job-generating firms and attempting to meet the needs of large numbers of their citizens who formerly received federal social and welfare aid. Further, much of the national money which is still available for economic development and social needs is now administered by state governments under block grants. States have seldom been responsive to such needs in urban areas. If our assessment of the negative effects of these policies on the viability of cities as governing units is correct, then the question that must be addressed is: what is to replace local government as the primary means for citizens to act collectively below the state level?     

Applications of Variance Reduction Techniques in Construction Simulation

A technique that can be used to reduce the variance of a stochastic simulation output is reviewed. This technique allows the user to reduce the number of simulation runs without sacrificing the level of confidence of the output. This technique entails inducing an artificial correlation between the various runs. The specific technique presented uses common random numbers (CRN). The use of CRN can be applied to the comparison of alternative systems. Using CRN when comparing alternatives insures that the comparison is properly conducted. A sample simulation is presented in order to illustrate these two applications of CRN.     

Thiamin, Riboflavin and Niacin Retention in Cooked Cowpeas as Affected by Kanwa Treatment

Retention of three water soluble B-vitamins in dry cowpeas cooked with a local tenderizer, named “kanwa,” were investigated. Results showed cooking (100°C) in kanwa or sodium bicarbonate decreased levels and retention of vitamins compared to controls cooked in water. Levels of vitamins in kanwa-cooked cowpeas were not significantly different from those in NaHCO₃ cooked samples. Retention in the alkaline cooking processes ranged 15–20% (thiamin), 26–49% (niacin) & 53–64% (riboflavin). Soaking followed by boiling at 100°C or pressure cooking (121°C) increased levels and retention of vitamins.     

Influence of temperature on crystallization of lactose in ice-cream

Sandiness in ice-cream due to lactose crystallization can still be a problem in many circumstances. Lactose crystallization occurs in ice-cream as the unfrozen phase becomes supersaturated. However, the effects of storage temperature and temperature fluctuations on lactose crystallization have not been very well quantified. In this work, an accelerated storage apparatus was used to determine the effects of thermal fluctuations (from ±0.01°C to ±2.0°C), at several mean storage temperatures (from −5.0 to −20.0°C), on the onset of lactose nucleation and subsequent crystal growth in a standard vanilla ice-cream. the induction time for nucleation initially decreased as temperature was lowered (for temperature oscillations of ±1.0°C), until a minimum induction time of 3 h was found between −10.0 and −12.0°C. Further decreases in storage temperature caused the induction time to increase. the induction time for nucleation increased as the extent of temperature fluctuations increased, from 0.01 to 2.0°C, while initial lactose crystal growth rate showed the opposite trend. the initial growth rate increased as temperature decreased between −5.0 and −10.0°C, but then decreased for temperatures below −10.0°C. At −20.0°C lactose crystals grew very slowly. At −10.0°C the rate of growth decreased with increasing amplitude of temperature oscillations.