A research on the effects of hurdle technologies in pathogen inactivation and shelf-life of fresh produce

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The antimicrobial activities of oregano and sumac extracts on shredded iceberg lettuce and whole tomatoes inoculated with Salmonella typhimurium ATCC 13311 were investigated. Iceberg lettuce and tomatoes were treated with three different washing procedures for 5, 10, 15 and 20 minutes. Five strain mixtures of Salmonella spp. were inoculated to shredded lettuce and whole tomatoes were treated with different concentrations of oregano and sumac extracts and packaged in air or in passive modified atmosphere conditions. Packaged produce were stored at 4ºC or 10ºC for 10 days and the numbers of Salmonella spp. were determined in 0., 1., 3., 7. and 10. days of storage. The change in natural microflora of produce was also investigated within storage period.
The results show that there was no istatistical difference between treatment times. Increase in natural extract concentrations caused the increase in reduction of S.typhimurium ATCC 13311. Results showed that sumac and oregano extracts can substantially reduce Salmonella spp. counts in produce, however increase in extract concentrations cause undesirable changes in the flavour and color of produce. Treatment of tomatoes with 1000 ppm oregano for 10 min caused a reduction of 5,10 log cfu/tomato, however decolorization of tomatoes was observed during treatment.
Passive modified atmosphere packaging had no significant effect on the aerobic mesophilic and psychrotrophic bacteria, mold and yeast, lactic acid bacteria and Salmonella spp. counts, when compared to the control. While there was not any substantial difference in Salmonella spp. numbers on lettuce stored 4ºC or 10ºC, significant difference between storage temperatures was observed in tomatoes. Lactic acid bacteria, aerobic mesophilic and psychrotrophic bacteria counts were not significant in different storage temperatures. Mold and yeast counts at 4ºC were significantly less than storaged at 10ºC.

Gülten Tiryaki Gündüz
Engelleme teknolojisinin sebzelerde patojen inaktivasyonu ve raf ömrü açısından etkilerinin araştırılması · 2008 · 211 sayfa.
Danışman: Doç. Dr. Şahika Aktuğ Gönül
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