In CGIAR Challenge Program on Water and Food. Challenge Program on Water and Food: background papers to the full proposal. Colombo, Sri Lanka: CGIAR Challenge Program on Water and Food.

Strains of Salmonella spp. with resistance to antimicrobial drugs are now widespread in both developed and developing countries. In developed countries it is now increasingly accepted that for the most part such strains are zoonotic in origin and acquire their resistance in the food-animal host before onward transmission to humans through the food chain. Of particular importance since the early 1990s has been a multiresistant strain of Salmonella typhimurium definitive phage type (DT) 104, displaying resistance to up to six commonly used antimicrobials, with about 15% of isolates also exhibiting decreased susceptibility to ciprofloxacin. Mutations in the gyrA gene in such isolates have been characterised by a PCR LightCycler-based gyrA mutation assay, and at least four different mutations have been identified. Multiple resistance (to four or more antimicrobials) is also common in the poultry-associated pathogens Salmonella virchow and Salmonella hadar, with an increasing number of strains of these serotypes exhibiting decreased susceptibility to ciprofloxacin. Multiple resistance is also being found in other serotypes in several other European countries, and has been associated with treatment failures. For Salmonella typhi, multiple drug resistance is now the norm in strains originating in the Indian subcontinent and south-east Asia. Such multiresistant strains have been responsible for several epidemics and some of these have been associated with contaminated water supplies. Furthermore, an increasing number of multiresistant strains of S. typhi are now exhibiting decreased susceptibility to ciprofloxacin, with concomitant treatment failures. In developed countries antimicrobial resistance in zoonotic salmonellas has been attributed to the injudicious use of antimicrobials in food-producing animals. It is hoped that the application of Codes of Practice for the use of such agents, which have been prepared by the pharmaceutical industry in response to widespread international concern about the development of drug resistance in bacterial pathogens, will now result in a widespread reduction in the incidence of drug-resistant salmonellas in food production animals and humans on an international scale.

The thermal reaction between cysteine and furfural was investigated at 65 degrees C in five-component food grade oil/water (O/W) microemulsions of R-(+)-limonene/ethanol, EtOH/water/propylene glycol, PG/Tween 60 as apart of a systematic study on the generation of aroma compounds by utilizing structured W/O and O/W fluids. The furfural-cysteine reaction led to the formation of unique aroma compounds such as 2-furfurylthiol (FFT), 2-(2-furanyl)thiazolidine (main reaction product), 2-(2-furanyl)-thiazoline, and N-(2-mercaptovinyl)-2-(2-furanyl)thiazolidine. These products were determined and characterized by GC-MS. Enhancement in flavor formation is termed "microemulsion catalysis". The chemical reaction occurs preferably at the interfacial film, and therefore a pseudophase model was assumed to explain the enhanced flavor formation. The product internal composition is dictated by process conditions such as temperature, time, pH, and mainly the nature of the interface. Increasing water/PG ratio leads to a dramatic increase in the initial reaction rate (V0). V0 increased linearly as a function of the aqueous phase content, which could be due to the increase in the interfacial concentration of furfural. Microemulsions offer a new reaction medium to produce selective aroma compounds and to optimize their formation.