Evaluation of biofilm formation and chemical sensitivity of Salmonella typhimurium on plastic surface.

S. typhimurium is an important socioeconomic problem in several countries, mainly in developing countries where it is reported as the main responsible for the food-borne disease outbreaks. A biofilm can be explained as a group of cells, diverse species or mono-species that are fixed to a surface and/or to one another. This study aimed to evaluate the biofilm formation of S. typhimurium on the plastic surface as well as to determine the relationship between contact time and incubation temperature. Crystal violet assay was performed to quantify the biofilm formation with and without treatments based on the value of optical density at 600nm of the destaining crystal violet at different interval of time. The outcomes of the result indicated that, the attachment of bacterial cells to the plastic surfaces increased with the increased contact time and determined by temperature. The values of OD600 at 37 °C for 24, 48 and 72 hours were 0.770, 0.968 and 2.363 respectively. This indicated that, the formation of biofilm by S. typhimurium on plastic surfaces varied with contact time. For the disinfectant treatments, hydrogen peroxide with 91 % sensitivity was the highest in treatment of S. typhimurium cells, followed by the mixture of sodium hypochloride and paracetic acid with 70 %, then paracetic acid with 67 %. Considering this result, S. typhimurium formed a biofilm on the plastic surface, hygienic activities on a plastic surface in food industry during handling, processing, distribution and storage of food should be a concerned and these disinfectants are suggested for the treatment of S. typhimurium.

Detection of Mycobacterium avium subspecies paratuberculosis in formula milk from Bogor using PCR IS 900.

Crohn’s disease (CD) that becomes a public health concern in developed countries shows similarities in clinical signs and pathological features with Johne’s disease (JD) in ruminants infected by Mycobacterium avium subspecies paratuberculosis (MAP). Few researches conducted in Europe, the USA, and Australia showed relationships between MAP, CD, JD and dairy products. Indonesians consume milk and diary products from domestic and imported source. Adji in 2004 found some domestic dairy cows that were seropositive for MAP, and this could be a serious problem in dairy farm animals and human health in the future. The aim of this study was to detect MAP in the growing up formula milk. Fifty samples from five established factories were taken from supermarkets in Bogor. Polymerase chain reaction method (PCR) with insertion sequence (IS) 900 as primer and culture in Herrold’s egg yolk media with mycobactin J (HEYM J) as a gold standard were used in this study. Neither MAP grew up in HEYM J medium after 20 weeks of culture period nor positive samples by PCR IS 900 were found. Although there were no positive samples found in this study, further extensive and comprehensive studies on MAP should be done with more and varied samples, as well as in human to provide data on MAP in Indonesia.