00000ctm a22000003a 4500 UP-99796217611830505 Buklod 20151014113904.0 a r |||| u| ta 151014s2015 xx d r |||| u| (iLib)UPD-00249811486 DCHE rda eng LG 993.5 2015 F66 B356 Ballesteros, Ma. Luisa P. author Inactivation of salmonella enterica serovars on different stainless steel surfaces using ultraviolet-c and atmospheric pressure plasma jet Ma. Luisa P. Ballesteros ; Alonso A. Gabriel, adviser. Quezon City College of Home Economics, University of the Philippines 2015. xii, 123 leaves 1 CD ROM type rdacontent unmediated rdamedia volume rdacarrier. Thesis (B.S. Food Technology)--University of the Philippines Diliman. This study aimed to evaluate the effectiveness of ultraviolet-C irradiation and atmospheric pressure plasma jet treatment as alternative methods for inactivation of Salmonella spp. on stainless steel surfaces used in food industry. Two types of stainless steel namely 304 and 316, were used as test surfaces with each type having three different finishes: 2B, Hair line (HL), and Mirror (MR) which were flooded with cocktail of Salmonella serovars in mid-stationary phase (17 h) and were allowed to adhere for 4 h. After adhesion, the stainless steel was drained, air-dried, and exposed to UV-C inactivation and atmospheric pressure plasma jet treatment. Survivors were then enumerated by swab-vortex method. Results showed that the test organism exhibited a biphasic UV-C inactivation composed of a fast log linear inactivation phase followed by a slower inactivation tail on all test surfaces. The D1 values calculated from the faster log linear inactivation phase ranged from 2.54 (316 2B and 316 HL) to 4.31 s (304 2B). The maximum population reduction calculated before the inactivation tail ranged from 3.32 (316 HL) to 4.97 log CFU/in^2 (304 MR). On the other hand, the test organism exhibited log linear inactivation in all surfaces treated with atmospheric plasma jet. The D values ranged from 2.66 (304 2B) to 3.43 s (316 MR). However, plasma treatment of metal surfaces resulted in abrupt increase in surface temperature (150 °C, 15 s), which could have significantly contributed to the observed inactivation. In addition, both the metal type and surface finish were observed not to affect the efficacies of UV-C inactivation and atmospheric pressure plasma jet treatment. The results obtained in the study demonstrated the potential of the tested physical treatments as alternatives to commonly used food contact surface chemical sanitation protocols. The observed limited efficacy of UV-C may be further enhanced by combining with other chemical disinfection treatments while atmospheric pressure plasma jet may be used solely as food surface disinfection. Ultraviolet radiation Industrial applications. Irradiation. Gabriel, Alonzo A. adviser. Also available in UP Diliman Digital Archives https://digitalarchives.upd.edu.ph/item/19331/971/vxOHDNIr6blLa1ePquw0cy8D FO UP UPD DCHE LG 993.5 2015 F66 B356 Thesis