Ravikant Agarwal

Interaction of Salmonella enterica Subspecies enterica Serovar Typhimurium and Mung Bean (Phaseolus aureus) Plants

The effect of Salmonella enterica subspecies enterica serovar Typhimurium, a zoonotic serovar, on mung bean (Phaseolus aureus) cultivar Pant Mung-3 plants was studied. Inoculation of mung bean seeds with Salmonella Typhimurium (7.2 x 10(5) CFU/ml) reduced sprouting rate (P < 0.07). This effect was more pronounced at higher levels of contamination. In the soil inoculated with Salmonella Typhimurium (7.2 x 10(6) CFU/g), germination was retarded and the number of defective sprouts was also significantly higher (P < 0.002). Salmonella Typhimurium grew inside germinating seeds and plant tissues and persisted in seedlings, adult plants, and harvested seedlings dried and stored at room temperature (30 degrees C) up to 45 days. Phaseolus aureus plants grown in sterile soil was resistant to Salmonella Typhimurium infection at 15 days of age and cleared Salmonella from all the aerial parts within 3 h of infection. However, Salmonella Typhimurium could be reisolated from the basal area of the stem and from soil even after 45 days of exposure to the pathogen.

Optimization of Various Essential Oils and Their Effect on the Microbial and Sensory Attributes of Chicken Sausages

The present study was undertaken to standardize the method for incorporation of essential oils (EOs) in chicken sausages. Swabbing was found to be the best method in comparison to direct or along with oil method, for incorporation of EOs into chicken sausages. This was followed by the optimization of various individual EOs viz., cassia oil and thyme oil, in fresh chicken sausages. In the first part of the study, based on the results of the total plate count and sensory scores, level of incorporation for cassia oil and thyme oil was optimized at 0.25 and 0.125%, respectively, in fresh chicken sausages. In the second part of study, on the basis of the results of total plate count and sensory attributes, blends of different EOs viz, Blend-1, Blend-2, Blend-3 were optimized each at 0.25% level and Blend-4 was optimized at 0.125% level for incorporation in emulsion-based chicken sausages. Thus, out of two individual EOs and four blends tried, Cassia oil and Blend-1 at 0.25% level each is recommended for use in fresh and emulsion-based chicken sausages, respectively.

Detection and Partial Purification of Salmonella serovar Typhimurium Cytotoxic Protein Affecting Seed Germination

Abstract Siddiqui, M.Z., Singh, B.R., Chandra, M., Agarwal, Ravi Kant, Agarwal, R.K. and Srivastava, S.K. 2007. Detection and partial purification of Salmonella serovar Typhimurium cytotoxic protein affecting seed germination. J. Appl. Anim. Res., 33: 77–79. Cells of a virulent strain of Salmonella Typhimurium (E-2391), a highly ubiquitous and zoonotic serovar, were sonicated and the cell-free supernatant was precipitated using increasing concentration of ammonium sulphate (30–80%). Inhibition of seed germination by various precipitated fractions revealed that the activity was present in the fraction precipitated at 70% saturation of ammonium sulphate. Out of the two peaks obtained on Seralose 6B chromatography, the second peak was found to possess germination-inhibition activity at a level as low as 0.1 mg/ml of this protein. SDS-PAGE revealed the presence of fewer proteins in the second peak but no specific protein responsible for the inhibition could be deduced. The study indicated that the in vitro seed germination inhibition technique can be utilized for testing of Salmonella isolates for the cytotoxic properties instead of resorting to expensive in vivo methods involving use of animals.