Irradiation in combination with higher storage temperatures maintains chip-making quality of potato.

Freshly harvested and well-suberized potato (Solanum tuberosum) of varieties Kufri Jyoti, Lady Rosata, Kufri Laukar, and Hermises were processed by radiation at 78/149 Gy (D(min)/D(max)) dose and stored at 12 +/- 2 degrees C for 8 mo from March to October for assessment of chip-making quality. The firmness of the tubers in all the varieties processed remained unchanged during the period of storage. Chips of the desirable quality could be prepared from 7-mo stored Lady Rosata, Hermises, and Kufri Jyoti varieties, whereas, in Kufri Laukar, the quality chips could be prepared with tubers stored not beyond 5 mo. In the present study, varietal differences were found to influence the chip-making quality of irradiated potato. Tubers with high reducing and total sugar (>2%) were found to be unsuitable for chip-making. The quality of chips, however, was not affected much by the change in internal color of the tuber during storage beyond 6 mo. The results suggested the efficacy of gamma irradiation for ensuring availability of the processing quality potato during lean periods from September to October.

Radiation processing to ensure safety of minimally processed carrot (Daucus carota) and cucumber (Cucumis sativus): optimization of dose for the elimination of Salmonella Typhimurium and Listeria monocytogenes.

Minimally processed vegetables are in demand, because they offer convenience to consumers. However, these products are often unsafe because of possible contamination with pathogens, such as Salmonella, Escherichia coli O157:H7, and Shigella species. Therefore, this study was carried out to optimize the radiation dose necessary to ensure the safety of precut carrot and cucumber. Decimal reduction doses (D-values) of Salmonella Typhimurium MTCC 98 were ca. 0.164 kGy in carrot samples and 0.178 kGy in cucumber samples. D-values of Listeria monocytogenes were determined to be 0.312 and 0.345 kGy in carrot and cucumber samples, respectively. Studies of inoculated, packaged, minimally processed carrot and cucumber samples showed that treatment with a 1-kGy dose of gamma radiation eliminated up to 4 log CFU/g of Salmonella Typhimurium and 3 log CFU/g of L. monocytogenes. However, treatment with a 2-kGy dose was necessary to eliminate these pathogens by 5 log CFU/g. Storage studies showed that both Salmonella Typhimurium and L. monocytogenes were able to grow at 10 degrees C in inoculated control samples. Neither of these pathogens could be recovered from radiation-processed samples after storage for up to 8 days.