Journal of applied microbiology 2017 11 16() doi 10.1111/jam.13638
The study aim was to evaluate the potential of 405 nm light as a virus intervention for blueberries.
METHODS AND RESULTS
Tulane virus-inoculated-blueberries were treated with 4.2 mW/sq cm of 405 nm light for 5 to 30 min. To mitigate thermal heating due to the intense light, a dry ice-chilled nitrogen-based cooling system was utilized. Blueberries were rotated to ensure exposure of all surfaces to 405 light. Five, 10, and 30 min treatments resulted in little or no inactivation of Tulane virus on blueberries (average log reductions of -0.18; -0.02; and +0.06 respectively). Since 405 nm light’s inactivation mechanism may involve singlet oxygen, two singlet oxygen enhancers, riboflavin and Rose bengal, were used to coat the blueberries prior to 405 nm treatment. When 0.1% riboflavin or Rose bengal was added, resulting in an average PFU reduction of – 0.51 and -1.01 logs, respectively. However it was noted that the addition of riboflavin and Rose bengal in the absence of 405 nm light treatment produced some inactivation. Average untreated log reductions for riboflavin and Rose bengal were -0.13 and -0.66, respectively. Also 60-30 second 405 nm light pulses with two minute ambient cooling periods without the dry ice-nitrogen cooling system did not inactivate Tulane virus, suggesting that oxygen limitation by the nitrogen CO2 mixture was not the cause of limited inactivation.
Overall results indicate that 405 nm light has some potential to inactivate viruses if singlet oxygen enhancers are present. This article is protected by copyright. All rights reserved.