Postharvest aspects in citrus fruit production: new insights on future treatments
Samir Droby
Department p of Postharvest Science, ARO, The Volcani Center
Competition p places p multiple p demands on citrus fruit suppliers Quantity Quality: • Taste (Brix/acid) • % Juice • Peel disorders • Firmness • Shelf life • Decay • Consistency
Cost On time delivery
Shi Shippers
Flexibility
Safety: microbial and pesticide
Specific requirements: • Packaging • Pallets • Size • Tailor made • Quarantine
Competition p places p multiple p demands on citrus fruit suppliers Quantity Quality: • Taste (Brix/acid) • % Juice • Peel disorders • Firmness • Shelf life • Decay • Consistency
Cost On time delivery
Shi Shippers
Flexibility
Pesticide residues
Specific requirements: • Packaging • Pallets • Size • Tailor made • Quarantine
Most frequent complains in the market Rind breakdown
Rind browning
QC
Decay
Oleo
color
Scales
Mechanical
Scaring
Shape size
Zero tolerance for decay in the market
Costly repacking at destination
Factors affecting development of postharvest decay of citrus fruit Storage conditions Temp. & RH Mechanical & physiological damage
Postharvest handling
Fruit quality / physiological status
Pre‐harvest history Type of package
Postharvest treatment of f citrus it f fruit it iin packhouse
Drencher
Water rinse
Water rinse Pressure Washer
detergent
Sorting
Wax Spray
Dryer Soak tank/ Spray over rollers
Dryer
Sorting S ti & packing
“Silver bullet approach”: f fungicides i id as the th only l treatment t t t lmazalil
MRL 5 ppm MRL 5 ppm
-2,4),2]-1dichlorophenyl)‐2‐(2‐ propenyloxy)ethyl]‐1H‐imidazole
Guazatine (Panoctine)
MRL 5 ppm
TBZ
MRL 5 ppm MRL 5 ppm
2-(1,3)-thiazol‐4‐yl)‐1H‐ benzoimidazole
OPP
MRL 10 ppm
N N''' (i i di 8 1 t di l) N,N'''‐(iminodi‐8,1‐octanediyl) Ortho‐phenylphenol
Timelines for fungicide introductions and first reports of resistance development to Penicillium digitatum on citrus fruit 23 yr.
SOPP &OPP
36
Harding 1959 Harding,
59 22 yr.
44
Biphenyl
Harding, 1962
62 8 yr.
62
TBZ
Dave/Petrie, 1970
70 11 yr.
Benomyl
62
Laville, 1973
73 7 yr.
80
Imazalil
87
Eckert c e t 1987 98
Fludioxonil
04
Pyrimethanil
04
?
04
Azoxystrobin 36
46
56
66
76
86
Year Introduced Figure derived from: Kaplan, Dave and Petrie, Proc. Int. Soc. Citriculture. 1981: 788-791
96
06
Fungicide application in the packhouse Spray
Drencher
Wax
Dip tank
On line Drencher
Mold infection and residues in fruit for different Imazalil concentrations in wax
FFruit dipped in a 500 ppm solution Iimazalil for 30 seconds can it di d i 500 l ti Ii lil f 30 d have a residue of between 0.75‐1.2ppm
Residue analysis of fungicides through out the p packing g season Mg/kg
Consolidation of forces to reduce pesticide residues – current situation • Food safety has become competitive among supermarket chains/supplyers • Complex •Each supermarket chain now have there own MRLs
• Not standardized
•Increased pressure by media and NGOs demanding I d b di d NGO d di – Codex produce free of chemical residues
– European Union •Pathogen resistance to fungicides – Individual I di id l •Key Fungicides have been withdrawn from the countries market
• “Organic” Organic
Recentt requirements R i t f for f fungicide i id residues in citrus fruit: Russia S. No.
1 2 3
Active g ingredients
Codex
2-4 D 1 mg/kg Imazalil 5 mg/kg Thiabendazole 10 mg/kg (TBZ)
EUH
1 mg/kg 5 mg/kg 5 mg/kg
Russia
0 0.1 mg/kg 1 mg/kg
What we can do to face this situation?
Understanding the basics: Disease is a process ……………… Spores Contamination
Infection
Germination
Decay develop.
48 h
Adopting “multi multi-hurdle/system hurdle/system approach� The hurdle concept: Combine several factors into hurdle effects that pathogens should not be able to overcome
Combination and complementary treatments
Initial incidence
100%
50% 50% effective
10%
80% effective
2% 80% effective
0.1% 80% effective
Minimizing postharvest losses of citrus fruit Prober use of sanitizers and fungicides Avoiding wounding
Orchard management & sanitation it ti
Pathological Maintaining cold chain
Packhouse P kh hygiene h i and sanitation Overcoming long delays at the shed
Level 1: the Orchard: • • • •
Preventing injury during harvest and transport Orchard sanitation (reducing inoculum) Optimal harvest timing Use sanitized harvest boxes/bins (reducing inoculum)
Level 2: arrival in the packhouse: • Transport and treat the fruit within 24 hours after harvest • Keep the fruit in shade • Drench with fungicides/sanitizers
Level 3: equipment and packhouse sanitation: • Packing line, floor should be cleaned on daily basis • Use of disinfectants, detergents • Monitor fungal g populations p p in the air and on the packline p
Before disinfection
After disinfection
Level 3: equipment and packhouse sanitation: • Keep dirty area clean during working hours • Separate dirty area from the rest of the packing line Exhaust fan
Level 4: Cooling, cleaning and sanitizing
cold rooms, m , containers and ship p compartments mp m
Level 5: Fungicide application Spray
water soak tank+ fungicide heated water
Curative: C ti eradication di ti of f Drenching Soak tank Application in wax& established infections protection
What is new in chemical control? Reduced risk fungicides for control of postharvest decay of citrus fruit Phenylpyrrole y py
Strobilurin
Scholar, Graduate (Fludioxonil)
Abound (Azoxystrobin)
Inhibition of signal g transduction (Protein kinase)
Inhibition of mitochondrial respiration
Anilinpyrimidine py Penbotec (Pyrimethanil)
Inhibition of amino acids and protein synthesis
Control of postharvest decay of citrus fruit by Scholar 5
Valencia - Paking house exp 4 Weeks in storage 5ยบC+ 1 week shelf 3 2 1 0 Water (HW)
Scholar 1000ppm in Scholar 500ppm in Imazalil 500 ppm in Wax HW +1000 ppm in HW+1000ppm in Wax Wax
4
Murcot - Paking house Exp Decay (%)
Decay (%)
4
3
3 Weeks at 5ยบC + 13 days Shelf 2
1
Natural decayy
0 Water (HW)
Scholar 1000ppm in Scholar 500ppm in Imazalil 500 ppm in Wax HW +1000 ppm in HW+1000ppm in Wax Wax
A+ Fludioxonil
Azoxystrobin
& 4-(2,2-difluoro-1,3b benzodioxol-4-yl)-1Hdi l 4 l) 1H pyrrole-3-carbonitrile
Methyl (E)-2-[2-[6-(2cyanophenoxy)pyrimidin-4yl]oxyphenyl]-3-methoxy-prop2-enoate
Registration expected 2010
P i th il Pyrimethanil
4,6-dimethyl-N-phenyl-2pyrimidinamine py
l lmazalil ll
& -2,4 2 4),2]-1dichlorophenyl)‐2‐(2‐ ) ( propenyloxy)ethyl]‐1H‐imidazole
Control of postharvest decay of citrus f it by fruit b Phil Philabuster b t Valencia
Decay (%)
60
10 d att 20 C 17 d at 5 C
40 20 0 Wax Only
Grapefruit
30
13 d at 10 C 4 d at 20 C
Decay (%)
25
Commecial Packhouse trial 2008
Philabuster 500 Philabuster 2000 Imazalil 500 ppm ppm in HW + wax ppm in wax in HW + 1000 ppm in wax
20 15 10 5 0 Wax Only
Philabuster 500 Philabuster 2000 Imazalil 500 ppm ppm in HW + wax ppm in wax in HW + 1000 ppm in wax
Fruit was wounded 24 hours before treatment
Pre-harvest application of fungicides to reduce postharvest decay Topsin and Benlate = same active ingredient thiophanate-methyl
Topsin
benomyl
Benlate carbendazim
Green mold % aftter degreening g or storage
Effects of pre-harvest applications of Topsin on postharvest decay 100
Kern Co. Lindcove1 Lindcove2
90
Control
80
Topsin
70 60 50 40 30 20 10 0 None
1,000
10,000
100,000
1,000,000
Inoculum density
J. Smilanick
California
Reducing chemical residues: Control Alternatives Soft and non-residual chemicals
Heat treatments
Possible alternatives: • “Curing” • OPP Combinations• of H two or Hot water • Sodium bicarbonate • Heated fungicide more alternatives • Quaternary ammonium solutions • Chlorine Chl i • Hot water dip or brush • Ozone • Electrolyzed water Biocontrol
Microbial biocontrol agents Microbial biocontrol
Pre-harvest practices
Growth regulators (GA 2 4 D) Growth regulators (GA, 2,4‐D)
Integrated Control of Postharvest Decay of Grapefruit 12
Decay (% %)
10
a
After 4 weeks at 11°C + 2 weeks at 20°C
8 6 4
bc
bc
b c
2 0 12
Decay (%)
10
After 4 weeks at 20°C
a
8 6 4 2
b
b
b
b
0
“Natural infection”
Control of decay in cold stored Oranges ( T (cv Tarocco)) 100 %
Decay (%) Non Treated Control
100
Shemer
80
Imazalyl+wax
60 40 20 0
7
14
21
Storage at 10 C (days) Italy, (Treatments included a hot carbonate prewash)
46
Thank you