Hermetic Storage Technology for Food Grains: New Beginning of Organic and Safe Storage for Farmers and Consumers: A Review

The moisture content of grains, oxygen and carbon dioxide concentration in storage environment affects the storage life of food grains. The moisture content affects on storability of food grains severely, hence the storage structures must be provided with sufficient protection from moisture exchange between grain and atmosphere. The insect and pests grows very fast in presence of oxygen and moisture in the storage environment. The humid climate provides favorable conditions to moulds and insects to grow in most of the food grains and oilseeds. The grains exposed to these favorable environment further not useful for human consumptions. Many harmful chemicals like aflatoxins are formed in oilseeds and cereals. The emerging hermatic storage is highly effective technology to prevent the spoilage of grains without use of any harmful fumigants and chemicals, hence it is popularly known as organic storage technology. In this technology the flow of oxygen and water from external environment is fully controlled by impermeable, triple layer hermatic plastic bags.

Use and efficacy of low temperature plasma in foods: promising intervention on aflatoxin control in maize in Kenya – A review

Maize (Zea mays var. indentata L.) is the most important food security crop in Kenya and plays an important role in human nutrition. Mycotoxins (MTs) are fungal toxic metabolites which naturally contaminate food and feed. When ingested, inhaled or adsorbed through the skin, even in very small concentrations, are associated with various cancers, retarded growth, suppressed immunity and mutations among other complications. Aflatoxins especially aflatoxin B1, are considered the most lethal in the group of more than three hundred known mycotoxins. In Kenya, aflatoxin contamination in maize leads to huge losses in the country’s breadbasket and also in the grain reserves. One of the possible methods for control of the aflatoxin menace in maize would be through the use of plasma technology. Plasma, an electrically energized matter in form of a gas that is generated at different atmospheric pressures, has several uses. At low temperature, it makes the process of decontamination practical, inexpensive and suitable for products whereby use of heat is not desired. Non thermal plasma, a new discipline in food processing has been shown to destroy micro-organisms including spores to undetectable levels. Over the years, there has been increased concern over the rising cases of aflatoxin poisoning in Kenya due to contaminated maize. The presence of aflatoxins is promoted by various factors, among them poor storage conditions, soil type, insect activity and drought conditions before harvest. Several measures including use of hermetic storage types such as pics (Purdue Improved Cowpea Storage) bags to store maize and proper drying of maize to the right moisture content to discourage mould growth have been suggested and used to tackle the aflatoxin menace. In Mexico and Caribbean countries, nixtamalization is widely practised and has been used to reduce aflatoxin in tortilla. Nixtamilization involves cooking the maize in an alkaline solution resulting in detoxification. The traditional nixtamalization and extrusion cooking processes have been combined in making of the dough (masa) for corn tortillas and have shown better success in elimination of aflatoxin. The main challenge with the use of this method of detoxification is acidification of aflatoxin extracts, which occurs during digestion and can lead to a rebuilding of the aflatoxin molecule leading to poisoning. The application of low temperature plasma technology can bring much needed reprieve in tackling the aflatoxin menace in maize and other foods both in Kenya and even worldwide.

Effect of Hypoxia on the Lethal Mortality Time of Adult Sitophilus oryzae L

Sitophilus oryzae is one of the most destructive pests of stored grains. It leads to significant quantitative and qualitative losses, resulting in food and income insecurity among farmers. Chemical pesticides are the most common methods used by farmers and other grain value chain actors to manage this pest. However, pesticides are increasingly becoming unattractive for pest control due to health hazards posed to applicators, consumers, the environment, and insect resistance. Modified atmospheres have the potential to manage stored insect pests as an alternative to pesticides. There is limited understanding of when insect pests die when grain is stored in airtight containers. This experiment was conducted to assess the time required to reach mortality of adult S. oryzae when exposed to 1, 3, and 5% oxygen levels. Results revealed that the LT50 for 1, 3, and 5% of oxygen were reached after 69.7 h, 187.8 h, and 386.6 h of exposure, respectively. No adult emergence was observed on infested grains following exposure to 1 and 3% oxygen levels. This result provides vital rationale for storing grain in hermetic storage conditions for at least 39 days to achieve adult S. oryzae mortality and minimize grain reinfestation.

Comparative Studies on Grain Quality and Pesticide Residues in Maize Stored in Hermetic and Polypropylene Storage Bags

The conventional method of grain storage involving the use of polypropylene bags in conjunction with pesticides and hermetic bags are paramount in developing countries. However, there is limited information on grain quality and pesticide residue concentration of maize stored in such bags. This work determined grain quality and pesticide residue concentrations of maize stored in polypropylene and hermetic storage bags. Maize samples stored for a period of one year in polypropylene and hermetic bags were obtained from three major maize growing communities in the Ashanti region of Ghana and were analyzed for grain quality, aflatoxin content and pesticide residue concentration using standard methods. The amount of diseased, discolored, broken, insect-damaged, stained, germinated, shriveled, total defective, inorganic and organic matter of maize stored in hermetic bags was significantly lower than that of polypropylene. Levels of aflatoxin in maize stored in the polypropylene bags were significantly higher (13.9 ppb–20 ppb) than in maize stored in the hermetic bags (0.90 ppb–2.6 ppb). Out of 35 pesticides screened, only lambda-cyhalothrin was detected in polypropylene bags and deltamethrin in hermetic bags. The presence of these pesticide residues may be due to their long-lasting abilities. Levels of lambda-cyhalothrin residues were above the maximum residue limit (MRL) of 0.02 mg/kg, but have no significant effect on health. Deltamethrin residue concentrations in hermetically stored maize samples were below the MRL. In conclusion, maize grains stored in hermetic bags have higher grain quality and lower aflatoxin and pesticide residue concentrations than polypropylene bags. Education and promotion on the utilization of hermetic bags should be a priority in storing and supplying safe maize grains to consumers.

Seed Longevity and Germination Behaviour in Eugenia roxburghii

Eugenia roxburghii is an evergreen graceful shrub with a tremendous potential as garden plant. As a part of ex-situ conservation and popularization of the species, seed longevity was studied by understanding the relationship of seed viability with respect to different moisture contents and storage temperature. Seeds are recognized as recalcitrant, being desiccation as well as chilling sensitive. During hermetic storage, seeds stored at 300C/70%RH retained viability for about 5 months and 4 months in 200C/20% RH. Seeds can be best stored for five months in laboratory conditions.

↵​​Effect of Hermetic Storage on Seed Quality Maintenance of Dolichos Bean [Lablab purpureus (L.) var Typicus Prain]

Background: Dolichos bean is one of the important vegetable legume crops. During storage, protection of seed from bruchid attack is a major problem worldwide. Once the bruchid attacks, the extent of damage could be up to 100%, leading to both quantitative and qualitative loss by making it unfit for consumption. Existing traditional methods are less effective or impractical and the use of chemical methods can be harmful to the farmers and consumers. So, there is urgent need of hermetic storage method for seed quality maintenance. Keeping in view, the present study was carried out to investigate on hermetic storage practices for seed quality maintenance. Methods: Triple-layer PICS technology, a chemical-free hermetic storage was evaluated for storage of dolichos bean to moisture content, germination and quality. Four different types of storage bags viz., jute bags, polythene bags, triple layer PICS bags and jute bags treated with chlorpyrifos were used for evaluating their efficacy in managing dolichos bean seed attributes. The data on various parameters pertaining to seed characteristics and changes in biochemical composition of dolichos bean seeds stored in different bags was recorded at every two month intervals for 3 times (2,4, and 6 months) by using standard protocols. Complete Randomized Design (CRD) (Snedecor and Cochran, 1967) was used for the data analysis. The data was subjected to statistical analysis as per the methods suggested by Panse and Sukhatme (1985). Result: Results on moisture content showed that, in case of storage in PICS bags, there was no decrease in seed moisture content at 2, 4 and 6 months respectively and germination percent in triple-layer PICS bag at 2, 4 and 6 months storage was highest among all bag types. Test weight (g), protein content (%) and carbohydrate content (%) at 2, 4 and 6 months storage respectively were higher in triple layer PICS bag. The mean fat content recorded was highest in jute bag (1.25%) and lowest in triple layer PICS bag (0.63%). Our study concludes that the triple layer PICS bags hermetic technology is efficient in managing maintaining same level of moisture content percent, germination percent and test weight compared to other bags over 3 different periods of storage. The triple layer PICS bags are also highly useful for retaining carbohydrate percent and protein percent at almost the same levels compared to initial values.