Hermetic Storage Research Articles

End-use quality characteristics of hermetically stored paddy

Four paddy varieties (Bg 352, Bg 300, Bg 358 and Bg 360) were stored in hermetic IRRI bags and common woven polyethylene bags (polybags) at room temperature either uninfested or infested with rice weevils (Sitophilus oryzae (L.)). After 9 months of storage, samples were tested for insect mortality, gas contents, moisture content (m.c.), thousand grain mass (TGM), porosity, hardness, whiteness, total milled rice yield (TMR), head rice yield (HRY), gelatinization temperature, amylose (AC), crude protein (CP), crude fat, free fatty acid (FFA), thiamine and niacin contents and sensory characteristics. These properties after storage were compared with their initial condition. The oxygen content dropped from 21% to 7% and 13.8% for infested and uninfested IRRI bag samples, respectively. The results showed that m.c., of the IRRI bag samples increased significantly (P < 0.05) by 5% when compared to the initial sample but it increased by 15% in polybag stored samples. After 9 months, dry matter loss (DM) was 65% higher in polybag than IRRI bag samples. Highest DM loss was observed in Bg 300 and the lowest DM loss was observed in Bg 358 and Bg 360. Paddy samples stored in IRRI bags showed reduced whiteness compared to polybag stored samples. Storage in IRRI bags significantly increased (P < 0.05) TMR, HRY, AC and sensory values compared to polybag samples. However, paddy samples stored in polybags significantly increased (P < 0.05) their CP and FFA contents while decreasing sensory values, thiamine and niacin contents. The FFA value of polybag samples was 2.5 times higher than IRRI bag samples. Hermetic storage of dry paddy improved overall paddy quality but different end-use quality parameters were observed in the two paddy grain types of short round (Bg 352 and Bg 300) or intermediate bold (Bg 358 and Bg 360).

Hermetic storage with plastic sealing to reduce insect infestation and secure paddy seed quality: A powerful strategy for rice farmers in Mozambique

Rice is the world's most important staple food and the basis of the diet of the majority of the population. In small farm agriculture, the yields obtained in cereal production are usually low and losses, both in the field and during storage, are dramatically high, particularly in developing countries. In Mozambique, these aspects, together with an increased frequency of floods, are hindering advances in rice production. Aimed at contributing to the reduction of losses in stored rice, trials were carried out to compare the effectiveness of traditional raffia bags and of hermetic storage using single and double plastic bags concerning quantitative losses and seed quality, including germination potential, after three and six months of storage. Pest identification, insect populations estimates, percentage of weight loss, germination power and seedling vigor were evaluated. The results showed that, in descending order of density, Angoumois grain moth (Sitotroga cerealella Olivier), lesser grain borer (Rhyzopertha dominica F.), rice/maize weevil (Sitophilus zeamais Mostch. and Sitophilus oryzae L.) and red flour beetle [Tribolium castaneum (Herbst)] were the main insects infesting the rice. When compared to hermetic storage with both single and duplicate airtight bags, traditional storage presented statistically significant higher mean infestation density (30.63–53.94 individuals/kg in traditional and 0.71–3.50 individuals/kg in hermetic storage) and percentage of weight loss (3.03–3.44% in traditional contrasting with 0.27–0.47% in hermetic conditions). In traditional storage a significant 38.25% drop in the germination potential was also observed, attaining values below the established minimum tolerated in Mozambique (80%), while under hermetic storage, that reduction remained within the acceptable values of 13.9–17.5%. The distinct storage methods did not produce significant differences on the moisture content of the grain. These results demonstrate that the use of hermetic storage has resulted in a safe, pesticide-free, and sustainable storage method, suitable for rice seeds, with advantages over traditional bagging. The results presented here lead to propose hermetic storage to be adopted by paddy small farmers, in order to lever food security and income generation in the country.

BIOINTENSIVE SAFE STORAGE METHODS FOR PULSES: REVIEW

ABSTRACT Pulses are an important source of protein in the Indian diet. Pulses are least preferred by farmers because of high risk and less remunerative than cereals; consequently, the production of the pulses is sufficiently low. To meet the demand of pulses, India is at present importing about 3 million tons. Pulse production systems including pre harvest and post harvest techniques. These techniques aremechanized in developed countries but developing countries still employ traditional techniques which incur losses of about 20–25% post-harvest losses. Drying and conditioning of pulses aremostly done by artificial methods; however, the most common drying method for pulses in the worldis open sun drying, particularly at farm level. Drying of pulses is essential because the moisturecontent at the time of harvesting is on the higher side (18–25%) and for safe storage, the optimummoisture content is in the range of 9–12% to avoid production of mycotoxins. Again storage of pulses is a challenging one since pulses are more sensitive to storage pest viz., bruchids and caneasily be attacked by them. Hence safe storage conditions like controlled atmosphere storage (CAS) must be provided for the pulses until they are being consumed. CAS offer a safe and environmentallybenign alternative to the use of conventional residue-producing chemical fumigants for controllinginsect pests that attack stored grain. Air tight containers or bins offer great protection in controllingbruchids. Hermetic storage (HS) technology has emerged as a significant alternative to other methods of storage that protect commodities from insects and molds. HS is based on the principle of generation of an oxygen-depleted, carbon dioxide-enriched interstitial atmosphere caused by therespiration of the living organisms in the ecological system of a sealed storage. Bag storage is acommon method in India. Pulses can also be stored either in metal bins, silo bags of various capacities.

Reducing CO2 accumulation and its phytotoxicity to lettuce with absorbent in hermetic storage as a simulation of long-term fumigation

Long-term fumigation with pure phosphine at low-temperature injures lettuce and the injury is likely caused by a potential accumulation of CO2. In this study, iceberg and romaine lettuce were stored hermetically in fumigation chambers with and without absorbents for CO2 and ethylene for 3days at 2ºC as a simulation of long-term fumigation to determine the effects of the absorbents on accumulations of CO2 and ethylene and postharvest quality of lettuce. In the absence of absorbents, CO2 level increased from 0.08% at the start to 3.36% at the end of the 3-day hermetic storage. No accumulation of ethylene was detected. Hermetic storage resulted in significant CO2 injuries to both iceberg and romaine lettuce and quality degradation as compared with the controls at 14days after treatment. In the storage with absorbents, the CO2 level remained low throughout the storage and ethylene was undetectable, and the CO2 injury level was the same or lower than the control. Lettuce quality scores were either the same or better than lettuce in the control. Our findings suggest that the accumulation of CO2 alone caused injuries associated with long-term phosphine fumigation and CO2 absorbent has the potential to prevent such injuries.

Aflatoxins and safe storage.

The paper examines both field experience and research on the prevention of the exponential growth of aflatoxins during multi-month post-harvest storage in hot, humid countries. The approach described is the application of modern safe storage methods using flexible, Ultra Hermetic™ structures that create an unbreatheable atmosphere through insect and microorganism respiration alone, without use of chemicals, fumigants, or pumps. Laboratory and field data are cited and specific examples are given describing the uses of Ultra Hermetic storage to prevent the growth of aflatoxins with their significant public health consequences. Also discussed is the presently limited quantitative information on the relative occurrence of excessive levels of aflatoxin (>20 ppb) before vs. after multi-month storage of such crops as maize, rice, and peanuts when under high humidity, high temperature conditions and, consequently, the need for further research to determine the frequency at which excessive aflatoxin levels are reached in the field vs. after months of post-harvest storage. The significant work being done to reduce aflatoxin levels in the field is mentioned, as well as its probable implications on post-harvest storage. Also described is why, with some crops such as peanuts, using Ultra Hermetic storage may require injection of carbon dioxide, or use of an oxygen absorber as an accelerant. The case of peanuts is discussed and experimental data is described.

PICS hermetic storage bags ineffective in controlling infestations of Prostephanus truncatus and Dinoderus spp. in traditional cassava chips

Cassava chips were stored for 8 months in PICS bags, with half of the bags having a natural initial insect infestation, and the other half having this initial natural infestation augmented with 50 Prostephanus truncatus adults. Chips stored in traditional woven polypropylene bags served as controls. Oxygen levels varied during storage from 19.98 to 17.56%, 20.4 to 18.40%, and 20.24 to 19.92%, respectively, in PICS bags with augmented infestation (PICS-A), PICS bags under natural infestation levels (PICS-N) and polypropylene bags (WPP). Carbon dioxide levels varied from 0.73 to 3.90%, 0.65–3.56%, and 0.20–0.61%, respectively, in the three types of bags. P. truncatus populations were significantly higher in PICS-A reaching 98.66 ± 7.21 individuals/kg at the end of storage, compared to 92.66 ± 4.71 in PICS-N and 100.55 ± 3.56 in WPP. Dinoderus spp. density was significantly higher in WPP with 270.55 ± 20.59 individuals/kg after 8 months. The number of holes on chips and weight losses also increased with storage duration in all three treatments, but were significantly higher in WPP. Holes created by insects were noticed in PICS bags and were more important in the inner HDPE (high-density polyethylene) layer than in the outer HDPE layer. Up to 1913.00 ± 114.13 holes were observed on the inner HDPE layer of PICS bags and 1039.00 ± 29.40 in the outer HDPE layer. Hermetic storage bags prolong the storability of chips by approximately 1 month. PICS efficacy was probably affected by the large size of traditional cassava chips with large airspaces between individual chips, leading to a large oxygen store for insects which could not be used up through biotic activity, so that bags were not hermetic. In conclusion, PICS bags cannot be recommended for the storage of large sized traditional cassava chips.

Adoption of on-farm hermetic storage for cowpea in West and Central Africa in 2012

This study is based on interviews with 3456 randomly selected cowpea farmers in 322 villages in ten countries in West and Central Africa in 2010 and 2012. It uses descriptive statistics to track the trends in adoption of cowpea storage technology compared to previous studies and Firth logistic regression to identify important factors in adoption. The interviews indicate that regionally about 46% of respondents use some type of hermetic storage for their cowpeas and about 44% of the quantity of cowpea stored on farms is in hermetic containers. Both the percentage of respondents and the percentage of stored quantity fall slightly short of the 50% benchmark hypothesized. The 2010–2012 estimates compare to about 30% of cowpea quantity stored in hermetic containers in 2003–2004. Regionally, the most commonly used hermetic storage container is the triple layer Purdue Improved Cowpea Storage (PICS) bag. In PICS villages, local unavailability is the most common reason for not using the bags. The logit analysis shows that living in a village with PICS activities is the single most important factor explaining adoption of the technology. In six of the nine regressions participation in the demonstrations was also positive and a statistically significant determinant of adoption. For someone living in a PICS village and participating in the activities the combined effect is highly influential. In Niger such an individual would be 27% more likely than a non-participant from a non-PICS village to use PICS bags. In Senegal he or she would be 55% more likely. Some form of exposure to PICS activities or village technicians is key in adoption of the PICS technologies, though it may not be direct contact with a PICS technician. On average additional cash flow due to storage of cowpea in PICS bags is estimated at $26.58/100 kg bag more than sale at harvest.

Adoption of cowpea hermetic storage by women in Nigeria, Niger and Burkina Faso

In this study, 2741 randomly selected rural women were interviewed about their cowpea storage practices in 101 villages in Burkina Faso, Niger and Nigeria in late 2010 and early 2011. The overall objective was to determine their cowpea storage practices and identify the most important factors in choosing Purdue Improved Crop Storage (PICS) triple bag storage. About two thirds of women said they used some type of hermetic storage. The hermetic containers included metal drums, plastic jugs, double bags and triple bags. The weighted percentage of women using PICS triple layer bags is 46%. Quantity of cowpea stored by technology showed similar patterns. Overall the percentage of cowpea in hermetic storage was 64%. The study estimated that women stored 50% of their cowpea in PICS bags. The percentage of cowpea in hermetic storage overall and in PICS bags specifically is higher for women than for men in a parallel 2012 ten-country study of mostly male household heads. In PICS villages, the women cite PICS technicians as the most important source of information. In Non-PICS villages, radio was the most important. Most women say that higher income is the major benefit of PICS. The 2009–2010 three country weighted average of the net cash flow from cowpea storage in PICS bags is $10.81/100 kg bag and $39.27 per respondent. Overall, the women indicated that local unavailability was the primary constraint to use of PICS bags. The LOGIT regression analysis shows that the most important factor influencing use of PICS technology is living in a village where PICS demonstrations occurred. The regression shows that radio and the PICS technicians have key roles as information sources. Being able to attend mixed gender meetings was statistically significant only in Burkina Faso where PICS did not organize many women-only PICS activities.

Portable hermetic storage bag resistant to Prostephanus truncatus, Rhyzopertha dominica, and Callosobruchus maculatus

Portable hermetic storage bag, SuperGrainbags™ (SGBs) was tested against insect penetration Prostephanus truncatus, Rhyzopertha dominica, and Callosobruchus maculatus. Measurements of oxygen level, insect mortality, and insect damage were determined during six weeks. A new type of multi-layer SGB-IV-R co-extruded, with its ultra-low oxygen permeability of less than 4 cc/m2/day filled with grains of maize, wheat, and cowpea allows a significant decrease in the oxygen level after two weeks of storage. By week 4, 100% mortality of insects is located inside the bag (≤5 insect/kg) was observed. However, the trapped insects placed between the SGB-IV-R and outer mesh cage with no deprivation of oxygen ultimately penetrated from the outside. Under artificial insect density at 10 insect/kg, the SGB-IV-R was punctured after 3 and 6 weeks by the P. truncatus and R. dominica, respectively but no for C. maculatus. In summary, when insect infestation is coming from grain harvest, successful control of all insects was achieved by SGB-IV-R, but effects of infestation from outside under natural (untrapped) field conditions needs to be validated.

Insight into Hypoxia Tolerance in Cowpea Bruchid: Metabolic Repression and Heat Shock Protein Regulation via Hypoxia-Inducible Factor 1

Oxygen is of fundamental importance for most living organisms including insects. Hermetic storage uses airtight containment facilities to withhold oxygen required for development, thus preventing damage by insect pests in stored grain. Cowpea bruchid (Callosobruchus maculatus) ceases feeding and growth when exposed to 2% oxygen. However, although population expansion is temporarily arrested, the bruchids (especially late stage larvae) can survive extended periods of hypoxia and recover development if normoxic conditions resume, an ability rarely found in mammals. To begin to understand fundamental mechanisms that enable insects to cope with oxygen deprivation, we constructed a 3′-anchored cDNA library from 4th instar larvae subjected to normoxic and hypoxic treatments (respectively), and performed 454-pyrosequencing. Quality filtering and contig assembly resulted in 20,846 unique sequences. Of these, 5,335 sequences had hits in BlastX searches (E = 10−6), constituting a 2,979 unigene set. Further analysis based on gene ontology terms indicated that 1,036 genes were involved in a diverse range of cellular functions. Genes encoding putative glycolytic and TCA cycle enzymes as well as components of respiratory chain complexes were selected and assessed for transcript responses to low oxygen. The majority of these genes were down-regulated, suggesting that hypoxia repressed metabolic activity. However, a group of genes encoding heat shock proteins (HSPs) was induced. Promoter analyses of representative HSP genes suggested the involvement of hypoxia-inducible transcription factor 1 (HIF1) in regulating these hypoxia-induced genes. Its activator function has been confirmed by transient co-transfection into S2 cells of constructs of HIF1 subunits and the HSP promoter-driven reporter.

Salient factors in the low utilization of PICS bags (triple-bagging) in Nasarawa local government area of Kano state, Nigeria

Thepaper asserts that cowpea is a major nutritional legume in West Africa and thatthe grain experiences great losses at postharvest stages especially at storage.It posits that hermetic storage which the PICS is one of have proved to be avery successful storage option for cowpea storage without the use of agrochemicals but that there are daunting problems with its utilization. The studyrevealed among others that having outlets where the PICS can be bought(29%),making the PICS cheaper (45%), convince grain merchants that the PICS is more effective than regular storagebags(19%), and lastly forcing it on grain merchants by government would lead to more usage of the PICS (7%). Basedon the opinion of the cowpea merchants it was recommended that the sellingprice of the PICS be reviewed downwards, and that there should be a massiveenlightenment campaign for the use of the PICS; advantages of the PICS overregular bags and how to use the PICS should be demonstrated in all grainmarkets in the region by extension bodies both public and private.

Effectiveness of hermetic systems in controlling maize storage pests in Kenya

To protect their maize from pests such as the larger grain borer (Prostephanus truncatus), and from theft, farmers in Africa are abandoning traditional storage structures: they shell their maize earlier and tend to store the grain inside the house in polypropylene bags. However, losses due to insects during storage remain high. Hermetic storage containers, such as metal silos (soldered airtight) and super grain bags (made from high-density polyethylene to reduce gas exchange), may enable farmers to reduce post-harvest losses. To test the different containers' effectiveness to control insect pests, on-station trials were conducted at three sites in Kenya under artificial infestation with maize weevils (Sitophilus zeamais) and larger grain borers (P. truncatus). The experiment consisted of six treatments, using three different types of containers and two different insecticides: i) polypropylene bags without insecticides; ii) polypropylene bags with Actellic Super; iii) super grain bags without insecticide; iv) metal silos without insecticide; v) metal silos with Actellic Super; and vi) metal silos with Phostoxin. Treatments were replicated three times per site. The results demonstrated that metal silos are very effective in controlling maize weevils and the larger grain borer. The use of both Actellic Super and Phostoxin in the metal silos did not lead to a significant increase in insect mortality or reduction in grain weight loss. Super grain bags controlled insect pests well, but insect mortality was not complete and all bags in the trial were perforated, almost certainly by P. truncatus. We conclude that it is technically feasible to control storage insects without insecticides in Africa by using hermetic storage, either metal silos or super bags. The super bags, however, might not be suitable in areas with a high incidence of P. truncatus.

Non-chemical on-farm hermetic maize storage in east Africa

Hermetic post-harvest maize storage can effectively control maize weevil, Sitophilus zeamais , which can be responsible for up to 50% damage to stored maize grain. Its use eliminates the need for toxic and expensive chemicals. Laboratory experiments were conducted on hermetic storage systems to evaluate the effects of temperature (10o vs. 27°C) and maize moistures (6.3 to 16%) on maize weevil biology and mortality rate, and to quantify weevil oxygen consumption. Ten-day weevil mortality was higher in hermetic vs. nonhermetic storage, in 6.3% moisture maize vs. 16%, and at a 27°C storage temperature vs. 10°C. Oxygen depletion results allow estimation of daily weevil oxygen consumption as a function of storage temperature and maize moisture for East Africa conditions. Keywords : Maize storage, Hermetic storage, Sitophilus zeamais , Maize weevil control, Maize deterioration

Advanced Grain Storage Methods for Quality Preservation and Insect Control Based on Aerated or Hermetic Storage and IPM

The grain industry is facing serious problems of insect and mite contamination due to restrictions placed on the use of chemical pesticides because of adverse effects of pesticide residues in grain and environment, resulting in strict limitations on pesticide registration by regulatory agencies. Consumer demand for chemical-free and insect contamination-free products is a general tendency, with which the grain industry finds it difficult to conform. In addition, in many countries, insects in particular have been developing resistance to contact insecticides and to the conventionally used phosphine gas. In temperate and cold climates, the most common non-chemical alternative to pesticides for cereal grain stored in bulk is the use of aeration systems during the winter that can effectively reduce grain temperature. In summer, refrigeration provides an excellent solution for quality maintenance of grain. In warm climates, for cereal grain stored in bags or in bulk, a new gaseous application technology that has successfully replaced fumigants is the manipulation of modified atmospheres (MAs) using biogenerated MAs, for insect control and for quality preservation of dry cereal grains and high moisture corn. Freshly harvested high moisture corn was successfully stored under hermetic conditions, thereby maintaining its quality prior to subsequent drying or processing into feeds or ethanol. These niche applications of MAs have resulted in very promising treatments with market acceptability. A new approach to the use of pheromones is the monitoring of insects based on remote sensing electronic transmitters that are progressively integrated into control programs. An IPM program that might integrate insect monitoring, aeration in winter, chilling with refrigerated air in summer in grain silos, biogenerated MAs, for insect control and for quality preservation of grain, and assisted MAs during storage of grain and at the final stages of the processed grain before packaging is proposed.

The use of modified and controlled atmospheres for the disinfestation of stored products

Storage insects are aerobic organisms requiring oxygen for their survival. Therefore, they respond to altered atmospheric gas compositions containing low O2 or high CO2. The lower the grain moisture content (m.c.) and the corresponding intergranular humidity, the higher the mortality—due to the desiccation effect on insects caused by low O2 or elevated CO2 concentrations. To achieve insect control, the temperature of the grain should be above 21 °C. Hermetic storage is based on the principle of generation of an oxygen-depleted, carbon dioxide-enriched interstitial atmosphere caused by the respiration of the living organisms in the ecological system of a sealed storage. A sufficiently low oxygen and elevated CO2 atmosphere is created through a natural metabolic process based on insect respiration and, in cases where the commodity has sufficiently high moisture, the respiration of the microorganisms within a sealed storage system. An O2 ingress rate of 0.05 %/day is sufficient to arrest the theoretical weight loss at a level of 0.018 % over 1-year storage period. At this ingress rate, the possibility of a residual surviving insect population is eliminated. This low O2 ingress level could serve as a guideline for the sealing specifications of structures appropriate to the hermetic storage method. The applications for which hermetic technology has been most widely accepted are (a) for long-term storage of cereal grains, primarily rice, corn, barley, and wheat; (b) for long-term storage of a variety of seeds to preserve germination potential and vigor, and (c) for quality preservation of high-value commodities, such as dried fruits.

Death by desiccation: Effects of hermetic storage on cowpea bruchids

When cowpea grain is stored in airtight containers, destructive populations of the cowpea bruchid (Callosobruchus maculatus) don’t develop even though the grain put into the store is already infested with sufficient C. maculatus to destroy the entire store within a few months. The surprising effectiveness of hermetic storage for preserving grain against insect pests has long been linked with the depletion of oxygen in the hermetic container and with the parallel rise in carbon dioxide. With C. maculatus, low oxygen (hypoxia) leads to cessation of larval feeding activity, whereas elevated levels of carbon dioxide (hypercarbia) have little or no effect on feeding. Cessation of feeding arrests the growth of the insects, which don’t mature and don’t reproduce. As a result, population growth ceases and damaging infestations don’t develop. C. maculatus eggs, larvae, and pupae subjected to hypoxia eventually die after exposures of various duration. The cause of death is desiccation resulting from an inadequate supply of water. We demonstrate that blocking the supply of oxygen interdicts the main supply of water for C. maculatus. This leads to inactivity, cessation of population growth, desiccation and eventual death.

Hermetic on-farm storage for maize weevil control in East Africa

Maize (Zea mays L.) consumption makes up over half of daily caloric intake of persons in East Africa and adequate supply is necessary for food security for subsistence farmers, as well as for domestic stability. Hermetic post-harvest maize storage is an attractive non-chemical control strategy for maize weevil,Sitophilus zeamais (Motsch.), which is the principal cause of insect damage to stored maize grain. Laboratory experiments were conducted on instrumented hermetic and non-hermetic containers to measure effects of temperature (10 vs. 27°C) and maize moistures (6.3 to 16%) on maize weevil biology and mortality rate, and to quantify weevil oxygen consumption. Ten days weevil mortality was significantly higher in hermetic vs. non-hermetic storage, in 6.3% moisture maize vs. 16%, and at 27°C storage temperature vs. 10°C. Oxygen depletion results allow estimation of days to 100% adult weevil mortality as a function of weevil infestation level, storage temperature and maize moisture for East Africa conditions. Key words: Maize storage, hermetic storage, Sitofilus zeamais, maize weevil, maize deterioration.

Pasting, morphological, thermal and crystallinity properties of starch isolated from beans stored under different atmospheric conditions

Few studies have elucidated the changes in starch properties during the long storage period, and none have explained the starch properties of bean grains stored under a nitrogen-modified atmosphere at a low-temperature. This study aims to evaluate the changes in pasting, morphological, thermal and crystallinity properties of starch isolated from carioca bean grains stored for 360 days under three different atmospheric conditions: hermetic storage at 5°C, a nitrogen-modified atmosphere at 15°C and a normal atmosphere at 25°C. The starch isolated from grains stored under nitrogen at 15°C did not differ in the solubility and pasting properties. However, they showed lower crystallinity, swelling power and heat that is necessary for gelatinisation compared to starch isolated from grains stored under a normal atmosphere at 25°C. Therefore, the storage under nitrogen-modified atmosphere is an alternative for the preservation of the thermal and crystallinity properties of bean starch.

Hermetic storage: A novel approach to the protection of cocoa beans

Hermetic storage has provided a successful storage method for protection of commodities without fumigants or need for refrigeration for insect control and quality preservation of stored products. Hermetic storage is achieved in specially constructed plastic structures for the preservation of cereal grains and other commodities. Plastic structures suitable for long-term storage systems, as well as intermediate storage of grain have been developed and applied. These storage systems based on the hermetic principle were designed for (1) storage at the farmercooperativeand small trader level with 10 - 1000 tonnes capacity for enclosing stacks termed Cocoons™, (2) small scale storage suitable for small portable containers of 60 kg to 2 tonnes called SuperGrainbags™ and (3)quality preservation, insect control and prevention of condensation during shipment of commodities in shipping containers known as ranSafeliners™. Hermetic storage is based on the principle of generation of an oxygendepleted, carbon dioxide-enriched interstitial atmosphere caused by the respiration of the living organisms in the ecological system of a sealed storage. A sufficiently low oxygen and elevated CO2, atmosphere is created through a natural metabolic process based on insect respiration and, in cases where the commodity has sufficiently high moisture, the respiration of the microorganisms within a sealed storage system. Applications for which hermetic technology has been most widely accepted are long-term storage of cereal grains, primarily rice, corn, barley,wheat and a variety of seeds to preserve germination potential and vigor and quality preservation of high-value commodities such as cocoa and coffee. Under field conditions in a cocoa bean storage facility in Makassar,Indonesia, a hermetically sealed flexible structure containing 6.7 tonnes of cocoa beans at an initial moisture content of 7.3% and relative humidity of 70% was monitored for oxygen concentration and quality parameters ofthe beans. The measurements showed a decrease in oxygen concentration to 0.3% after 5.5 days. No insects survived the oxygen depleted biogenerated atmosphere. Similar trials were carried out in Ghana by COCOBOD in which three stacks for hermetic storage and one stack each for conventional storage (without fumigation) and standard storage (with fumigation) were built for sampling and observation. At the sixth week of storage 100% mortality of insects was recorded in the CocoonTM. All the cocoa beans inside the CocoonTM maintained their quality category throughout the storage period and the grade remained the same after nine weeks of storage as it was at the beginning of the experiment.

Rice seed quality development and temperature during late development and maturation

AbstractThe potential longevity of japonica rice (Oryza sativa L. subsp. japonica) seed is particularly sensitive to high temperature – and thus climate change – during development and maturation. Cultivar Taipei 309 was grown at 28/20°C (12 h/12 h) and then from 19 DAA (days after 50% anthesis), when seeds were just over half filled, at 28/20°C, 30/22°C, 32/24°C or 34/26°C (12 h/12 h). Whereas ability to germinate ex planta had been achieved in almost all seeds by 24 DAA, only half the population were desiccation tolerant. Desiccation tolerance continued to increase over the subsequent 28 d, similarly at all four temperatures. Subsequent longevity, assessed by p50 (period in days to reduce viability to 50% in hermetic storage at 40°C with c. 15% moisture content), increased progressively at 28/20°C until 38 DAA, and remained constant until the final harvest (52 DAA). The three warmer temperature regimes provided similar longevity to 28/20°C at any one harvest, except at 38 DAA where the warmest (34/26°C) was poorer. That temperature regime also provided greater seed-to-seed variability within each survival curve. The results confirm that appreciable improvement in seed quality occurs during seed development and also subsequent maturation in japonica rice, but that increase in temperature from 28/20°C to 34/26°C during late seed filling onwards has comparatively little effect thereon. Comparison with previous investigations suggests that seed quality development may be less sensitive to high temperatures during late development and maturation than during the early seed development that precedes it.