High CO2 Reduces Spoilage Caused by Botrytis cinerea in Strawberry Without Impairing Fruit Quality

Abstract

High CO2 (> 20 kPa) conditions are beneficial for suppressing spoilage caused by Botrytis cinerea in strawberry fruit; however, these conditions are often accompanied by discoloration, off-flavors, and faster softening. Stepwise increments of CO2 concentrations have been proposed to alleviate injuries in fruits caused by high CO2. In this study, we investigated whether stepwise increments of CO2, up to 30 kPa and under a reduced O2 concentration, are beneficial for reducing fungal spoilage without inducing CO2 injury symptoms in strawberry fruit. Based on recommended settings (5–10 kPa O2 with 15–20 kPa CO2), we first selected optimal O2 and CO2 concentrations that best-reduced spoilage caused by B. cinerea in red ripe “Sonsation” strawberry fruit. We found that higher O2 (10 kPa) and CO2 (20 kPa) concentrations were most beneficial for prolonging strawberry fruit shelf life. Subsequently, we studied the performance of red ripe “Arabella” strawberry fruit stored at 5°C under different controlled atmosphere (CA) conditions (10 kPa O2 with either 0, 20, or 30 kPa CO2). The CO2 concentrations were achieved either within 8 h or in a stepwise manner within the first 4 days of storage. As a control, 21 kPa O2 and 0 kPa CO2 were used. Following storage for up to 11 days, the spoilage incidence was assessed at 12°C for 5 days. The application of high CO2 (20 and 30 kPa) combined with 10 kPa O2 greatly suppressed fruit spoilage during storage and subsequent shelf life. High CO2 suppressed respiration as well as maintained a higher pH and firmness in treated fruit. The level of total sugars did not change, but during storage, a substantial part of sucrose was converted into glucose and fructose, especially under high CO2 conditions. High CO2 did not affect ascorbic acid and anthocyanin levels. The stepwise increments of CO2 did not result in beneficial effects compared to the static application of high CO2. Our results show that “Arabella” strawberry fruit are highly tolerant to elevated CO2 and can be stored under 30 kPa CO2 to prolong the shelf life.

Recent Progress in Modified Atmosphere Packaging and Biopolymeric Films and Coatings for Fresh Strawberry Shelf‐Life Extension

“…Among these, avoiding condensation inside packages is crucial, because it has been extensively demonstrated that this phenomenon plays a key role in mould growth and decay [55]. In addition, acting on internal gaseous atmospheric composition has been reported to be a successful strategy, where reductions of O 2 concentration to 10% and increased CO 2 concentration (15%-20%) can help limit Botrytis growth [56]. This can be explained by a reduced strawberry metabolic rate due to reduced O 2 concentrations, thus delaying senescence, whereas high CO 2 concentrations exhibit bacteriostatic and fungistatic effects.…”

“…In packaging experiments, Botrytis or other pathogens, if present, are usually quantified by visual inspection, determining ‘fungal decay’ or ‘decay incidence’ as the number of decayed fruits over the total number of fruits in a package (%) [47, 56]. Strawberry microbiological quality can also be characterized in terms of total aerobic mesophilic counts, yeast and mould counts and coliforms [57, 58].…”

Strawberry Grey Mould, a Devastating Disease Caused by the Airborne Fungal Pathogen Botrytis cinerea

“…Soil sterilization at 55°C for 15 min proved lethal to Botrytis spp. It is clear that greenhouse conditions are easier to handle with field-grown strawberries, however some other techniques can be applied to both field and greenhouse crops; good soil drainage, putting straw mulches or polythene cover to reduce the plant and soil-surface contact (Legard et al, 2000 andFedele et al, 2020), choosing the correct time and rate of fertilizer applications, weeds management (weeds increase the infection of Botrytis spp., impede air circulation, and can be a source of inoculum), eliminating of rotten strawberries frequently and remove them away (Legard et al, 2000 andWilliamson et al, 2007), planting in raised beds and effective pruning (Legard et al, 2000;Li et al, 2022 andXiao et al, 2022).…”

“…A delay of one hour highlighted the amplification of post-harvest losses due to grey mould. Storage at these low temperatures is essential to retard grey mould and slow fruit respiration (Droby et al, 2009;Feliziani andRomanazzi, 2016 andLi et al, 2022).…”

“…cinerea interaction, the microenvironment and its antagonists on the host plant is essential for a good choice of a control strategy against B. cinerea (Boff et al, 2001;Blanco et al, 2006 andFedele et al, 2020). Although chemical control (Ortuno et al, 2014 andFeliziani andRomanazzi, 2016) and resistant cultivars (Evenhuis andWanten, 2006 andPelayo-Zaldívar et al, 2007) is the mainstays of B. cinerea management, there are other types of management strategies, such as biological control (De Angelis et al, 2022) and cultural activities (Fedele et al, 2020;Li et al, 2022 andXiao et al, 2022).…”