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Prof. Shlomo Navarro Green Storage Ltd. Israel Effects of modified atmospheres on insects with special reference to.

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Presentation on theme: "Prof. Shlomo Navarro Green Storage Ltd. Israel Effects of modified atmospheres on insects with special reference to."— Presentation transcript:

1 Prof. Shlomo Navarro Green Storage Ltd. Israel Effects of modified atmospheres on insects with special reference to silo-bags October 14, 2014 Navarro - Effects of MA on insects in silo-bags 1

2 October 14, 2014Navarro - Effects of MA on insects in silo-bags2 Modified atmospheres and hermetic storage take advantage of the basic fact that Storage insects are aerobic organisms requiring oxygen for their survival

3 October 14, 2014Navarro - Effects of MA on insects in silo-bags3 Action of modified atmospheres on insects 1- Desiccation 2- Anoxia 3- Hypercarbia

4 October 14, 2014Navarro - Effects of MA on insects in silo-bags4 A moth larva with spiracles along the body

5 October 14, 2014Navarro - Effects of MA on insects in silo-bags5 What is hermetic storage? It consists of generation of an oxygen-depleted and carbon dioxide-enriched interstitial atmosphere by the respiration of the living organisms in the ecological system of a sealed storage. hermetic storage is a type of biogenerated MA

6 October 14, 2014Navarro - Effects of MA on insects in silo-bags6 Organisms that contribute to the generation of MAs Insects and mitesInsects and mites Aerobic microfloraAerobic microflora Anaerobic microfloraAnaerobic microflora Seed germSeed germ

7 October 14, 2014Navarro - Effects of MA on insects in silo-bags7 Bio-generation of MAs in relation to the atmospheric gas composition and the humidity of their environment < 65% RH Insects & mites 65 to 85% RH Aerobic fungi, seed germ > 85% RH Anaerobic bacteria Aerobic conditions High oxygen Low carbon dioxide Anaerobic conditions Low oxygen High carbon dioxide

8 October 14, 2014Navarro - Effects of MA on insects in silo-bags8 First challenge in MA and hermetic storage Maintaining a well sealed storage structure

9 October 14, 2014Navarro - Effects of MA on insects in silo-bags9 Day Night Heated air expands Cooled air contracts

10 October 14, 2014Navarro - Effects of MA on insects in silo-bags10 Atmospheric pressure

11 October 14, 2014Navarro - Effects of MA on insects in silo-bags11 At low atmospheric pressure At high atmosphericpressure At high atmospheric pressure Inside atmosphere moves out External atmosphere moves in

12 October 14, 2014Navarro - Effects of MA on insects in silo-bags12 Parameters to determine GASTIGHTNESS of the structure 1- Leaks of the structure. Can be assessed using pressure test. 2- Permeability of the membrane, particularly in flexible structures. Should be measured in a laboratory.

13 October 14, 2014Navarro - Effects of MA on insects in silo-bags13 Second challenge in MA and hermetic storage Preventing permeation of oxygen through the flexible liners

14 October 14, 2014Navarro - Effects of MA on insects in silo-bags14 Oxygen permeability requirements [mL/(m 2 24 h)] of liners in relation to various storage capacities (m 3 ) and oxygen ingress rates (%/24 h) for successful application of hermetic storage of dry grain. Oxygen permeability requirements [mL/(m 2 24 h)] of liners in relation to various storage capacities (m 3 ) and oxygen ingress rates (%/24 h) for successful application of hermetic storage of dry grain.

15 C - Aeration period B - Exposure period A – Carbon dioxide distribution Third challenge in MA and hermetic storage Absorption and adsorption of carbon dioxide by the commodity October 14, 2014 Navarro - Effects of MA on insects in silo-bags 15

16 Recommended ranges for variable pressure test carried out in structures destined for gaseous treatments to control storage insects. < Type of gaseous treatment Structure volume in cubic meters Variable pressure test decay time (min) 250 to 125 Pa Empty structure 95% Full Fumigants < to 2, ,000 to 15, Controlled atmospheres Modified atmospheres including airtight storage < to 2,000 2,000 to 15,000 < to 2,000 2,000 to 15,000 October 14, 2014 Navarro - Effects of MA on insects in silo-bags 16

17 Phosphine loss from an empty structure of 7.5 m 3 capacity in relation to half-life pressure decay time. Phosphine loss should not exceed 100 ppm/day PH3 loss (ppm/day) Minutes for half-life pressure decay Shaded Exposed October 14, 2014 Navarro - Effects of MA on insects in silo-bags 17

18 October 14, 2014Navarro - Effects of MA on insects in silo-bags18 Fourth challenge in MA and hermetic storage Liner durability: 1.Insect damage 2.Rodent damage 3.Weather damage, mainly UV. 4.Mechanical damage

19 October 14, 2014Navarro - Effects of MA on insects in silo-bags19 Low O 2 ingress level, is difficult to maintain in rigid structures, but is achievable in practice using flexible liners

20 October 14, 2014Navarro - Effects of MA on insects in silo-bags20 Measured CO 2 concentration during storage time of three silo-bags with soybeans at 11.5%, 12.9% and 14.9% m.c. and average ambient temperature (adapted from Bartosik, 2008).

21 October 14, 2014Navarro - Effects of MA on insects in silo-bags21 Calculated O 2 and CO 2 concentration in silo-bags containing wheat of initial m.c. at 12, 14 and 16% w.b. for locations at Saenz Pe ס at Pergamino and Balcarce. Initial temperature 25 o C (adapted from Baretto et al., 2012) Calculated O 2 and CO 2 concentration in silo-bags containing wheat of initial m.c. at 12, 14 and 16% w.b. for locations at Saenz Pe ס at Pergamino and Balcarce. Initial temperature 25 o C (adapted from Baretto et al., 2012).

22 October 14, 2014Navarro - Effects of MA on insects in silo-bags22 Application of BIOGENERATED atmospheres on dry cereal grain

23 October 14, 2014Navarro - Effects of MA on insects in silo-bags23 The process of hermetic storage Insect respiration Oxygen ingress rate 0.05 %/day Residual oxygen within the hermetic storage Critical point

24 October 14, 2014Navarro - Effects of MA on insects in silo-bags24 Modified atmosphere generated by respiration of insects in hermetic storage (calculated theoretical). Based on grain mass containing different infestation levels of insects with an oxygen ingress ra א e of O.24%/day.

25 October 14, 2014Navarro - Effects of MA on insects in silo-bags25 Calculated weight-loss from a grain mass containing initial infestation of 2 insects/kg, at different oxygen ingress rates. Target gas tightness level

26 October 14, 2014Navarro - Effects of MA on insects in silo-bags26 Target gas tightness to control storage insects in dry cereals, in hermetic storage structures Daily oxygen ingress rate: 1- Below 0.05 % O 2 /day prevents oscillated oxygen concentration and increased weight loss. 2- Between 0.05 and 0.24 % O 2 /day allows oscillated oxygen concentration and increased weight loss.

27 October 14, 2014Navarro - Effects of MA on insects in silo-bags27 Conclusions MA or hermetic storage are very promising quality preservation and insect control technologies.MA or hermetic storage are very promising quality preservation and insect control technologies. There are a number of challenges in the application of MA or hermetic storage:There are a number of challenges in the application of MA or hermetic storage: 1.Maintaining a well sealed storage structure. 2.Preventing permeation of gas through the structural membrane (by improved liners). 3.Consider absorption and adsorption of carbon dioxide by the commodity. 4.In flexible storages improve liner durability; to insect damage; to rodent damage; to weather; and to mechanical damage. 5.For silo-bags daily oxygen ingress rate should be below 0.10 % O 2 /day. 6.For silo-bags oxygen permeability requirements of liners should be below 400 [mL/(m 2 24 h)]

28 October 14, 2014Navarro - Effects of MA on insects in silo-bags28 Thank you for your attention !!! Silobags for sealed storage of grain


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