It is storing an emergency supply of food and water for use in adversity. Food storage allows food to be eaten for some time (typically weeks to months) after harvest rather than solely immediately. Food is stored by almost every human society and by many animals. It is both a traditional domestic skill in the form of food logistics and an important industrial and commercial activity. Food preservation, storage, and transport, including timely delivery to consumers are important to food security, especially for the majority of people throughout the world who rely on others to produce their food. Storing of food has several purposes:
- It helps in preserving dry items like rice and flour or pantry food like oil and spices for further use in cooking.
- It prevents the wastage of food as storage of food checks its contamination.
- Reducing kitchen waste as uneaten or unused food can be preserved for a longer period, so it can be used when required.
- Even the cooked food can be stored in the refrigerator so that they can consume it after some time.
- It is necessary to meet the needs of nutrition and a balanced diet of the people.
- Stored food can be used during the off-season and emergency conditions like a catastrophe, famine, and drought.
- Food storage provides employment to poor people.
- It also provides foreign money as stored food grains can be exported to other countries.
- It protects the food from animals or theft.
IMPORTANT POINTS TO BE CONSIDERED DURING STORAGE
Food stored under unsuitable conditions should not be purchased or used because of the risk of spoilage. When in doubt about the safety of the food, throw it out as quickly as possible. Following are the points for safe storage of food:
Avoid storing foods in direct sunlight as sunlight promotes oxidation and subsequent loss of the food’s nutritional value and quality. Also, fat-soluble vitamins, such as A, D, E, and K are particularly sensitive to light degradation. It is far better to block sunlight on windows and rely on artificial illumination for the time the storeroom is in use.
The temperature has more to do with how long well-dried foods can be stored as the storage life of most foods is cut in half by every increase of 10°C. There is probably a limit as to how far this statement can be taken, but a reasonable expectation of self-life may be extrapolated from room temperature down to freezing. No doubt, the inverse could also be considered true. Storage temperature should be between 10°C to 20°C; the cooler, the better. Cool storage reduces respiratory activity and the degradation of enzymes, reduces internal water loss, and inhibits the growth of decay-producing organisms; and in some foods such as fruits, it slows the production of ethylene, a naturally occurring ripening agent. In addition, the storeroom should be free of un-insulated steam and water pipes, water heaters, transformers, refrigeration condensing units, steam generators, or other heat-producing equipment.
To reduce the risk of bacterial contamination, Ready-to-Eat (RTE) foods must be stored in the refrigerator kept below 5°C. These foods are often classified as ‘high-risk foods and include meat, poultry, dairy, seafood, eggs, and cooked rice and pasta. Casseroles, quiche, pasta, salad, pizza, sandwiches, and many cakes are also referred to as ready-to-eat foods that have high-risk foods as ingredients.
Ideally, storage areas should have a humidity level of 15% or less. Unless the storeroom is located in the desert, consider air conditioning or dehumidification during the most humid times of the year. A second option is to use moisture impervious packaging. Ideally, there is no reason not to use both. Maintain stored foods in their original packages whenever possible. Most packaging is designed for the food it contains and will remain in good condition for its given shelf life in the absence of temperature and humidity abuse.
As part of maintaining optimal temperature, it is suggested that adequate ventilation should be provided (some air exchange rate is absolutely essential). To take this to another level, consider air especially oxygen as a major threat to the quality of food. The less head gas (<2% 0,) in a container or package, the longer its shelf life is maintained. There is a maximum chance that moisture-proof packaging is airtight.
STORAGE OF FOOD ITEMS
All food has a limited shelf life which depends on the food type, packaging, and its storing. Proper storage of food is very important to avoid contamination and keep it as it is for a longer span of time. It can be stored in the field itself, at ambient temperature under room conditions or refrigerated storage conditions.
A. In-situ Storage
In-situ storage means on-site storage of fruits and vegetables by delaying the harvest until the crop is required, under natural or field conditions. In this, preferably root (carrot, sweet potato, cassava) tuber (potato), and rhizome (ginger) crops are left as such in the soil until preparation for the market. Demerit of this method is that the land where the crop is grown remains occupied and the new crops cannot be planted there.
B. Ambient Storage
In most cases, food is stored under ambient conditions at room temperature. The guidelines for ambient storage of different food items are summarized below:
Grains: Grain such as wheat, rice, millet, and so on, can be stored in rigid sealed metal containers preferably stainless steel to prevent it from moisture and or insect or rodent infestation. For kitchen use, plastic containers are the most traditional ones although metal cans are more preferable. Storage of grain in sacks is ineffective as mold and pests may destroy a cloth sack of grain in a year, even if stored off the ground in a dry area. On the ground or damp place, grain can spoil in as little as three days, it might have to be wash and dried before milling.
Vegetables: Different vegetables have different characteristics, so the guidelines vary for the safe storage of vegetables under dry conditions. There are many factors that affect the amount of time that a vegetable can be kept in dry storage, although temperature and humidity are the important ones. The following guideline shows the required temperature and humidity under dry storage conditions:
- Cool and dry (0-13°C, 50-60%): Onion and Garlic.
- Cool and moist (0-4°C, 90-95%): Root vegetable, potato, cole crops, and legumes.
- Cool and moist (13-10°C, 80-90%): Squash and melons, brinjal, beans, and okra.
- Warm and dry (13-16°C, 60-70%): Pumpkin and sweet potatoes.
- Warm and moist (13-61°C, 80-85%): Tomato.
Apart from the above many, there are innovative ways of storing vegetables other than dry storage so that they can be stored for several months between harvest seasons. These are the preservation techniques like pickling, home canning, food dehydration, or storage in a root. cellar.
Spices and herbs: Spices and herbs are today often sold prepackaged in plastic containers or re-sealable plastic packaging, which is convenient for pantry storage. This packaging has dual purposes of both storing and dispensing spices or herbs. When spices or herbs are homegrown or bought in bulk, they can be stored at home in glass or plastic containers. They can be stored even for years, however, after six months to a year, spices and herbs will gradually lose their flavor as oils they contain slowly evaporates during storage.
Oils: Oils can begin to go rancid quickly when not stored safely as oxygen, light, and heat all contribute to cooking oils becoming rancid. Rancid cooking oils do not often smell rancid until well after they have spoiled. Higher the level of polyunsaturated fatty acid (PUFA) in an oil viz. sunflower (60%), soybean (60%), linseed (52%), sesame (42%), peanut (32%); faster it spoils. To help preserve oils from rancidification, they should be stored in a dark place, oxygen safe, and light-reducing containers (dark glass or metal).
Unopened oils can have a storage life of up to one year, but some types have a shorter shelf-life even when unopened such as linseed. Once opened, these oils should be refrigerated and used within a few weeks.
Meat: The storage of fresh meat is a complex discipline that affects the costs, storage life, and eating quality of the meat. Appropriate techniques such as curing vary with the kind of meat and the particular requirements. Some of the materials added during the curing of meats serve to reduce the risks of food poisoning from anaerobic bacteria such as Clostridium spp. which releases botulinum toxin. Typical ingredients of curing agents that inhibit anaerobic bacteria include nitrates which are dangerously poisonous in their own right and must be added in carefully controlled quantities and according to proper techniques. Modern techniques of preparing meat for storage vary with the type of meat and special requirements of tenderness, flavor, hygiene, and economy.
C. Low-Temperature Storage
Low temperature slows down the growth of microorganisms and the rate of chemical as well as enzymatic changes in food, thus storage at a low temperature substantially reduces the rate at which food will deteriorate. Before cooling large amounts of food should always be divided into small to medium lots and packaged, as it can take many hours for the center of a large container to cool to a temperature to stop the growth of microbes. Package foods to be frozen in moisture, vapor-resistant material meant for freezing. This may be cold storage or refrigerated storage:
Cold Storage: Cold storage is a special kind of room, the temperature of which is kept very low with the help of machines and precision instruments. It is essential for extending the shelf life and period of marketing, avoiding glut, reducing transport bottlenecks during the peak periods of production, and maintenance of the quality of produce. Commercially apples, potatoes, and oranges are stored on large scale in cold storage. Other important costly raw materials like dry fruits, processed foods, frozen meat, fish, and eggs are being stored in cold storage. During cold storage rooms of different storage must be separated by insulation and should be protected from moisture. Whenever possible, one coating of foam glass with vapor-proof material should be used against the outside wall.
Refrigerated Storage: Perishable food like fruits (except pineapple and banana). vegetables (except potato, onion, garlic, pumpkin, and squashes), dairy products (milk. cream, and butter), and eggs should be stored in a refrigerator as it will maintain the quality and considerably lengthen storage life.
Alternative methods for storing herbs include freezing in water (chopped and added in an ice cube tray containing water) and stirred into a bowl with unsalted butter, then spread on wax paper and rolled into a cylinder shape. The ice cube or wax paper roll containing herbs is then kept in a freezer bag and stored in a freezer and can be cut off in the desired amount for cooking. Stored herbs using this technique must be used within a year.
Eggs should be stored in their carton in the refrigerator itself rather than on the door where the temperature is warmer. Unpreserved meat has only a relatively short life in storage so it should be refrigerated or frozen. Wrapped fresh meat can be kept safely for up to three days and unwrapped fresh meat up to five days at cold temperatures of 0° to 3°C. Wrapped meat remains moist and maintains its quality but surface growth of microorganisms is encouraged and the meat becomes slimy after about three days. When meat is stored unwrapped, the exposed surface dries out which retards microbial growth, but over-drying causes undesirable color changes and loss of flavor.
Food that has been kept in the Temperature Danger Zone (5°-63°C) for between two to four hours cannot be put back in the refrigerator and must be consumed. Any food which remains in the Temperature Danger Zone for four or more hours must be discarded as freezing does not destroy microbes present in food but inactivate the microbes (bacteria, yeasts, and molds). Hot food which is to be refrigerated or frozen should first be put in separate shallow containers to allow it to cool faster, rather than being left in one container.
Time Temperature Abuse
It happens when the food is exposed to Temperature Danger Zone (5°C-63°C) for more than 4 hrs. Time Temperature Abuse occurs when:
- Food is not stored, prepared, or held at a required temperature.
- Food is not cooked or reheated to temperatures high enough to kill harmful microorganisms.
- Food is not cooled low enough fast.
- Food is prepared in advance and not set to a safe required internal temperature while the food is on hold preventing Time Temperature Abuse.
To check the Time-Temperature Abuse
- Never expose the food to the temperature danger zone for more than 4 hours, except cool down. Try to pass the food through the danger zone quickly.
- Keep hot foods hot and cold foods cold.
- Don’t keep the food at all and the internal temperature should be 63°C to prevent harmful microbes from growing.
- Document temperatures and time during receiving, storage, preparation, holding, serving, cooling, and reheating.
COOKING AND REHEATING/THAWING FOOD
When it comes to cooking and reheating food, the temperature is just as important as storing food. Even if food has been properly frozen or refrigerated, there will still likely be some bacteria present; so heating food to a safe temperature will lower the risk of food poisoning. Al food product is said to be thawed when the core temperature of the product reaches between 1-5°C. Food should never be thawed at room temperature, this increases the risk of bacterial and fungal growth and accordingly the risk of food poisoning. Frozen food should be thawed in potable running water (at 15°C or below for note more than 90 min.) or in cold water (place food in a watertight, plastic bag; change the water every 30 minutes) or in the refrigerator (below 4°C) or during cooking (through heat or microwave). However, once food has been thawed, the microbes in thawed food can multiply to levels that can lead to foodborne illness, so this food should be used and never refrozen.
High-risk food must be heated to at least 75° Celsius in order to reduce the number of bacteria to a safe level of consumption. Once the food has been heated to this temperature it should not be allowed to drop under 63°C until it is served. This goes for both cooking and reheating food and the best way to monitor the temperature is through a food thermometer. After the food has been cooked to this temperature it should be eaten or refrigerated within two hours.