The application of various disinfectants by fogging for decreasing postharvest diseases of strawberry

doi:10.1016/j.postharvbio.2011.11.008

Postharvest Biology and Technology

Volume 66, April 2012, Pages 30-34

https://doi.org/10.1016/j.postharvbio.2011.11.008 Get rights and content

Abstract

In this study, chlorine dioxide (ClO₂), sodium hypochlorite (NaClO), hydrogen peroxide (H₂O₂), citric acid (C₆H₈O₇) and ethanol (EtOH) were applied to strawberry fruit using a fogger with an ultrasonic aerosol generator that can produce spheres at 1.2 μm in diameter. Fruit were treated at room temperature for 30 min while with the fogger operating and for an additional 30 min in the fog consisting of disinfectants. Treated fruit were stored at 1 °C for 5 days and an additional 2 days at 20 °C. The percentage of infected fruit and microorganism populations on the surface of the fruit and in the storage air were evaluated to determine the efficacy of treatments. Chlorine dioxide, hydrogen peroxide, sodium hypochlorite, citric acid and ethanol significantly reduced the percentage of infected fruit. The percentage of decay was reduced to 14.5% from 83.2% by the hydrogen peroxide treatment at 2000 μL L⁻¹ and to 32.5% by sodium hypochlorite at 2000 μL L⁻¹ in the first experiment. In addition, all chemicals significantly reduced the total number of microorganisms on the fruit surface and in the storage atmosphere. Hydrogen peroxide at 2000 μL L⁻¹ achieved approximately a 2 log reduction on the surface microorganism population in the first experiment. The study showed that application of disinfectants by fogging was effective in reducing postharvest diseases of strawberry.

Highlights

► Fogging with chlorine dioxide, sodium hypochlorite, hydrogen peroxide, citric acid, and ethanol achieved control of postharvest diseases of strawberry. ► Fogging also reduced microbial populations on the surface of fruit and in the storage atmosphere. ► The use of disinfectants by fogging is compatible with postharvest processing of strawberries. ► The use of disinfectants by fogging may be implemented in containers, refrigerated trucks used in transportation or in storage units.

Introduction

The storage period and the shelf life of strawberries are very short due to perishability and susceptibility to rot-causing pathogens (El-Kazzaz et al., 1983, Li and Kader, 1989, Lattanzio et al., 1996). The most severe postharvest diseases of strawberries are gray mould (Botrytis cinerea Pers.ex.Fr.) and Rhizopus rot (Rhizopus stolonifer Ehrenb.Fr.Vuill.) (Ceponis et al., 1987, Maas, 1992) that cause severe losses during storage and long-distance transport from cold store to market.

The control of postharvest diseases of strawberries is most commonly accomplished by using synthetic fungicides, particularly in the preharvest phase. However, particularly during postharvest storage and handling, the need to minimize chemical use, due to concerns about environmental pollution and the inability to control fungal diseases because of the development of fungicide-tolerant strains of pathogens (Leroux, 2007), have encouraged the rapid development of alternative approaches. One of the new approaches is the use of ‘generally recognized as safe’ (GRAS) products due to minimal concerns about their environmental impact and low residues in the treated commodity. The US Food and Drug Administration (FDA) has lists of GRAS products that can be used in many food processing applications where they have been declared safe by expert panels (http://www.fda.gov/Food/FoodIngredientsPackaging/GenerallyRecognizedasSafeGRAS/default.htm, 2011).

Regarding the FDA list as a reference, among the chemicals used in this study, chlorine dioxide (ClO₂), hydrogen peroxide (H₂O₂), citric acid (C₆H₈O₇), and ethanol (EtOH) are listed as GRAS substances. Sodium hypochlorite (NaClO) was tested in this study as a reference chemical because it is still widely used by industry due to low cost and high efficacy. All these substances are active antimicrobial agents and have been used in the food industry (Benarde et al., 1965, Larson and Morton, 1991, Maris, 1995, Bloomfield, 1996, Simmons et al., 1997). The aqueous application of chlorine dioxide, sodium hypochlorite, hydrogen peroxide, citric acid, and ethanol in the postharvest phase is effective for controlling postharvest diseases of several vegetables and fruit (Zoffoli et al., 1999, Delaqualis et al., 2004, Allende et al., 2008, Kanetis et al., 2008). In contrast, some fruit such as strawberry cannot be washed due to several factors. The fruit skin may be damaged easily when washing on a processing line and the drying period delays precooling that may facilitate pathogen infection. Therefore, application by fogging may be promising since handling and wetting of the fruit is minimized. Postharvest chlorine dioxide application by fogging has significantly controlled postharvest diseases of fig (Karabulut et al., 2009).

The objective of this study was to evaluate the efficacy of chlorine dioxide, sodium hypochlorite, hydrogen peroxide, citric acid and ethanol applications by fogging to control postharvest diseases of strawberry.

Section snippets

Fruit material

Three experiments were conducted on strawberries (Fragaria × ananassa Duch. L.) to test the efficacy of various disinfectants. Two strawberry cultivars were used in the experiments. ‘Sweet Charlie’ fruit used in the first experiment were harvested from an open field in Keles, Bursa. ‘Yalova-9’ fruit used in the second and third experiments were obtained from green houses in Antalya. The period between the harvest and application of chemicals was approximately 3 h in the first experiment and 10 h in

Results

In the three experiments, the natural incidence of decay, most of which was gray mould (80–90%), was significantly reduced by chlorine dioxide, hydrogen peroxide, sodium hypochlorite, citric acid, and ethanol fogging. In addition, microorganisms on the fruit surface and in the atmosphere of cold storage unit were significantly reduced by all treatments. None of treatments affected the visual quality and taste of fruit (data not shown).

In the first experiment, the fog of hydrogen peroxide at

Discussion

The result of this study demonstrated that postharvest application of chlorine dioxide, hydrogen peroxide, sodium hypochlorite, citric acid and ethanol by fogging was effective in controlling postharvest diseases of strawberries.

In three replicated experiments, postharvest application of chlorine dioxide, hydrogen peroxide, sodium hypochlorite, citric acid and ethanol fogging significantly reduced the postharvest decay on ‘Sweet Charlie’ and ‘Yalova 09’ strawberries. Our work corroborates

Acknowledgment

This study is partially financed by an Uludag University Scientific Research Committee project UAP(Z)-2010/13.

References (36)

A. Allende et al.
Role of commercial sanitizers and washing systems on epiphytic microorganisms and sensory quality of fresh-cut escarole and lettuce
Postharvest Biol. Technol.
(2008)
J.E. Alvaro et al.
Effects of peracetic acid disinfectant on the postharvest of some fresh vegetables
J. Food Eng.
(2009)
M. Brennan et al.
Postharvest treatment with citric acid or hydrogen peroxide to extend the shelf life of fresh sliced mushrooms
Lebensm. – Wiss. u. – Technol.
(2000)
M.A. Del Nobile et al.
Influence of postharvest treatments and film permeability on quality decay kinetics of minimally processed grapes
Postharvest Biol. Technol.
(2008)
O.A. Karabulut et al.
Postharvest ethanol and potassium sorbate treatments of table grapes to control gray mold
Postharvest Biol. Technol.
(2005)
O.A. Karabulut et al.
Evaluation of the use of chlorine dioxide by fogging for decreasing postharvest decay of fig
Postharvest Biol. Technol.
(2009)
V. Lattanzio et al.
Antifungal activity of 2,5-dimethoxybenzoic acid on postharvest pathogens of strawberry fruits
Postharvest Biol. Technol.
(1996)
S.D. Richardson et al.
Occurrence, genotoxicity, and carcinogenicity of regulated and emerging disinfection by-products in drinking water: a review and roadmap for research
Mutat. Res. – Rev. Mutat.
(2007)
G.E. Simmons et al.
Reduction of microbial populations on prunes by vapor phase hydrogen peroxide
J. Food Protect.
(1997)
D.O. Ukuku et al.
Effect of hot water and hydrogen peroxide treatments on survival of salmonella and microbial quality of whole and fresh-cut cantaloupe
J. Food Protect.
(2004)

J.P. Zoffoli et al.

Modified atmosphere packaging using chlorine gas generators to prevent Botrytis cinerea on table grapes

Postharvest Biol. Technol.

(1999)

R. Barkai-Golan

Reinfestation of citrus fruits by pathogenic fungi in the packing house

Israel J. Agric. Res.

(1966)

J.A. Bartz et al.

Chlorine concentration and the inoculation of tomato fruit in packing house dump tanks

Plant Dis.

(2001)

M.A. Benarde et al.

Efficiency of chlorine dioxide as a bactericide

Appl. Microbiol.

(1965)

S.F. Bloomfield

Chlorine and iodine formulations

M.J. Ceponis et al.

Disorders in sweet cherry and strawberry shipments to the New York market

Plant Dis.

(1987)

P.J. Delaqualis et al.

Implications of wash water chlorination and temperature for the microbiological and sensory properties of fresh-cut iceberg lettuce

Postharvest Biol. Technol.

(2004)

J.H. Du et al.

Effects of chlorine dioxide gas on postharvest physiology and storage quality of green bell pepper (Capsicum frutescens L. var. Longrum)

Agric. Sci. China

(2007)

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The application of various disinfectants by fogging for decreasing postharvest diseases of strawberry

Abstract

Highlights

Introduction

Section snippets

Fruit material

Results

Discussion

Acknowledgment

Postharvest Biol. Technol.

J. Food Eng.

Lebensm. – Wiss. u. – Technol.

Postharvest Biol. Technol.

Postharvest Biol. Technol.

Postharvest Biol. Technol.

Postharvest Biol. Technol.

Mutat. Res. – Rev. Mutat.

J. Food Protect.

J. Food Protect.

Postharvest Biol. Technol.

Reinfestation of citrus fruits by pathogenic fungi in the packing house

Israel J. Agric. Res.

Chlorine concentration and the inoculation of tomato fruit in packing house dump tanks

Plant Dis.

Efficiency of chlorine dioxide as a bactericide

Appl. Microbiol.

Chlorine and iodine formulations

Disorders in sweet cherry and strawberry shipments to the New York market

Plant Dis.

Implications of wash water chlorination and temperature for the microbiological and sensory properties of fresh-cut iceberg lettuce

Postharvest Biol. Technol.

Effects of chlorine dioxide gas on postharvest physiology and storage quality of green bell pepper (Capsicum frutescens L. var. Longrum)

Agric. Sci. China