Surveillance study of salmonella in fresh peppers (capsicum annuum l.) and inactivation by high hydrostatic pressure treatment

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2014
Polat Kılıç, Özlem Gözde
The main objective of this study was to investigate distribution of Salmonella in fresh peppers in Turkey. To serve this purpose, a total of 255 fresh pepper samples (green, kapya, bell, mazamort and charleston) were collected from 3 districts within 9 supermarkets and 3 bazaars in Ankara, Turkey. Salmonella suspected colonies was confirmed by using polymerase chain reaction (PCR) of Salmonella specific gene, invA. One of isolate was assigned as Salmonella, which was isolated from kapya pepper. Confirmed Salmonella isolate was characterized using phenotypic (serotyping) and genotypic (multilocus sequence typing, MLST and pulsed field gel electrophoresis, PFGE) methods. In MLST analysis, seven gene (aroC, dnaN, hemD, hisD, purE, sucA and thrA) MLST method designed by University College Cork were used. Within the scope of PFGE, total number of 4 Salmonella isolates was analyzed to compare with our Salmonella isolate and molecular subtyping of our strain exhibited different PFGE pattern. For the last section of this study High Hydrostatic Pressure (HHP) was carried out to inoculated sliced peppers. Salmonella was not detected in 1 ml of suspension from HHP treated (500 MPa, 25°C, 5 min) peppers. HHP treated fresh pepper samples stored at 25°C and 4°C for 7 days. After 7 days storage there was no any colony was count on TSA at 4°C but Salmonella colonies were re-growth at 25°C. This result demonstrated Salmonella cells were injured with the 500 MPa pressure treatments. HHP treated (500 MPa) fresh peppers can be safely consumed at refrigeration temperatures.