Postharvest UV-C treatment combined with 1-methylcyclopropene (1-MCP), followed by storage in continuous low-level ethylene atmosphere,improves the quality of tomatoes

Mature green tomatoes (Solanum lycopersicum L. cv Neang Pich) were exposed to 13.6 kJ m^?2 UV-C or 0.5 μL L^?1 1-MCP or combination of 13.6 kJ m^?2 UV-C and 0.5 μL L^?1 1-MCP, with appropriate untreated controls. After treatment, tomatoes were stored in air containing 0.1 μL L^?1 ethylene at 20°C and 100% RH. The untreated fruit ripened significantly faster than those of all other treatments. UV-C treatment alone was able to delay fruit ripening by up to 5 days longer compared to untreated fruits whilst the additional of 1-MCP further delayed fruit ripening. UV-C and 1-MCP treatments alone or in combination had significantly slower ethylene production rates throughout the storage period. The fruit treated with the combination of 1-MCP and UV-C was significantly firmer and had higher total phenolic content compared to that of the other treatments. However, there was no difference between treatments in soluble solids content/titratable acids ratio, chlorophyll content, lycopene content and total antioxidant activity. These results show that UV-C and 1-MCP treatment delay ripening and improve the quality of tomatoes in the presence of low-level ethylene during storage. This new treatment could be used to extend the shelf-life of mature green tomatoes through the supply chain without the use of refrigeration.     

A Comparison of Immersion, Immersion/Oral Combination and Injection Methods for the Vaccination of Channel Catfish Ictalurus punctatus Against Edwardsiella ictaluri

Abstract.— Four different vaccination regimes, including non-vaccinated controls (C), immersion/oral combination (IO). late immersion (LI), and injection (IJ), were evaluated for antibody production and protection from challenge in channel catfish Ictalurus punctatus that were hatched and raised in recirculating culture systems over a 28-wk period. For IO, fry were vaccinated by immersion on day 12 post-hatch and given an oral booster during week 10 post-hatch. The LI and IJ delivered vaccine was also administered at week 10 post-hatch. No titers were detected in the IO group prior to the oral booster at week 10. Mean titers rose sharply after the week 10 vaccinations in all treatment groups, maintained a high level for about 8 wk, and slowly declined over the next 4 wk. Injected fish had significantly higher titers during the primary response period than either LI or IO fish. There was no statistical difference in titers between LI and IO fish during the primary response. After an oral booster delivered during week 22, titers in LI and IO fish increased significantly at week 25, while titers in IJ fish declined despite the booster delivery. An immersion booster delivered during week 25 resulted in significant increases in titers in all vaccinated groups. Of multiple challenges, the only one not marred by concurrent columnaris infections revealed a low, but significant level of protection in IJ fish at 12 wk post-vaccination.     

Use of low-pressure storage to improve the quality of tomatoes

Freshly harvested vine-ripened tomatoes (Solanum lycopersicum cv. Neang Pich) were stored at low pressure (4 kPa) at 10°C for 11 days with 100% RH. Fruit quality was examined upon removal and after being transferred to normal atmosphere (101 kPa) at 20°C for 3 days. Weight loss was significantly lower in fruits which were stored at low pressure (4 kPa) than in fruits that were stored at regular atmosphere (101 kPa) at 10°C. Fruits that were stored at low pressure (4 kPa) reduced calyx browning by 12.5%, and calyx rots by 16%, compared to fruits that were stored at regular atmosphere (101 kPa) at 10°C. Fruit firmness was not significantly different between fruits stored at low pressures (4 kPa) and the normal atmosphere (101 kPa), with an average firmness of 14 N after fruits were stored at 10°C for 11 days. There was no difference in the SSC/TA ratio. The results suggest that a low pressure of 4 kPa at 10°C has potential as an alternative, non-chemical postharvest treatment to improve tomato quality during storage.     

Effect of low-pressure storage on the quality of green capsicums (Capsicum annum L.)

Green capsicums (Capsicum annum L.) were stored under low pressure (4 kPa) at 10°C for 5 and 11 days with 100% RH. The results showed that the incidence of stem decay under low-pressure storage for 5 and 11 days and storage at ambient atmosphere at 20°C for 3 days was lower compared to fruits that were stored at regular atmosphere at 10°C. Fruit that had been stored at low pressure at 10°C had no symptoms of flesh rots for up to 11 days, whilst fruit which had been stored at regular atmosphere at 10°C had 6% flesh rots after 11 days storage at 10°C.There was no difference in flesh firmness and colour retention between fruits stored at low pressure and regular pressure at 10°C. Capsicums stored at low pressure had higher overall acceptability compared to fruit that were stored at regular atmosphere at 10°C. These results demonstrate the potential of low pressure storage as an effective technique to manage capsicum fruit quality, however, there was no additional benefit when fruits were stored at low pressure for more than 5 days.