Use of chlorine dioxide gas for the postharvest control of Alternaria alternata and Stemphylium vesicarium on Roma tomatoes.

Background: Tomatoes and potatoes are the top produce affected in terms of value lost in the USA. Postharvest losses can occur anywhere from the time of harvest to the consumers' decision to eat or discard the food. These data support the importance of finding sustainable strategies to minimise food waste and preserve resources. This study evaluated the potential application of chlorine dioxide gas (ClO2 ) technology to control the postharvest spoilage of Roma tomatoes by Alternaria alternata and Stemphylium vesicarium.

Results: Data analysis showed that exposure time was a significant factor for fungal disease control (P < 0.05). After 3 min of treatment, mycelial growth was completely inhibited for A. alternata and S. vesicarium. Similar results were observed for conidial germination. The efficacy of ClO2 treatments was also studied under in vivo conditions. While untreated Roma tomatoes developed white moulds and black spots after 5 days of storage, produce decay was significantly (P < 0.05) delayed after 5 and 7 min treatments for S. vesicarium and A. alternata respectively.

Conclusion: The use of ClO2 in the food industry is regulated by both the FDA and the EPA. Currently, only acidified sodium chlorite solutions are approved for the control of micro-organisms in water used to wash fruits and vegetables. No direct applications of ClO2 gas on fresh fruits and vegetables can be found in the regulations. More data are required by the two agencies to demonstrate that residues of ClO2 on produce surfaces are acceptable for human consumption.