Satellite-based meteorological drought indicator to support food security in Java Island.

A meteorological drought refers to reduced rainfall conditions and is a great challenge to food security. Information of a meteorological drought in advance is important for taking actions in anticipation of its effects, but this can be difficult for areas with limited or sparse ground observation data available. In this study, a meteorological drought indicator was approached by applying the Standardized Precipitation Index (SPI) to satellite-based precipitation products from multiple sources. The SPI based meteorological drought analysis was then applied to Java Island, in particular to the largest rice-producing districts of Indonesia. A comparison with ground observation data showed that the satellite products accurately described meteorological drought events in Java both spatially and temporally. Meteorological droughts of the eight largest rice-producing districts in Java were modulated by the natural variations in El Niño and a positive-phase Indian Ocean Dipole (IOD). The drought severity was found to be dependent on the intensity of El Niño and a positive-phase IOD that occurs simultaneously, while the duration seems to be modulated more by the positive-phase IOD. The results demonstrate the potential applicability of satellite-based precipitation monitoring to predicting meteorological drought conditions several months in advance and preparing for their effects.

Influence of Cultural Conditions on Cytotoxin Production by Salmonella enteritidis.

The ability of Salmonella enteritidis strain 11013 to produce cytotoxic activity against Vero cells was determined under different cultural conditions. The toxin, which was not neutralizable with antiserum to Shiga toxin or Escherichia coli verotoxin-1 or verotoxin-2, was principally cell-associated and was produced primarily during the early stationary phase of growth. Trypticase soy broth was the best of three media evaluated for toxin production. Bacteria produced toxin in the range of pH 4.5 to 8.0 and at 12 to 42°C, with the optimal pH and temperature for toxin production at pH 7.0 and 37°C, respectively. Release of cellular cytotoxin into growth media was induced by growing salmonellae at extremes of pH (4.5 or 8.0) or at high incubation temperature (42°C). The Vero cell CD50 of S. enteritidis lysates of cells grown under optimal conditions was a titer of 150 ± 50 per mg of lysate protein. Although the significance of ingesting preformed Salmonella cytotoxin in human disease is unknown, it can be implied from these results that toxin would not be produced in foods held refrigerated at ≤7°C or acidified at ≤pH 4.0.