Storing organic vegetables

Even the most conservative estimates suggest that approximately thirty percent of marketable vegetable produce is lost each year due to poor handling and storage in the period following harvest. On a global scale this represents a significant quantity of food, enough to support very large populations such as China or India’s. In line with a general emphasis on sustainability, organic vegetable production should be dedicated to minimizing waste and inefficiencies associated with inadequate storage procedures.

Anyone who’s old enough might recall extreme shortages of fresh fruit and vegetables in Britain during the Second World War. Some popular historians attribute this to the breakdown of agriculture caused by labor and equipment shortages. I’ve recently conducted my own research and located material which challenges this viewpoint. During the early years of the war, agricultural production increased marginally in several important sectors. One of these was vegetables. Why then were so many children from London, Manchester, and Glasgow chronically malnourished and scurvy afflicted? It appears one of the most significant factors was a systemic failure to maintain effective distribution and storage for the produce grown in the majority of rural districts.

Local archives of farm records and correspondence frequently reveal the levels of difficulty and frustration experienced by commercial growers. In a letter to his uncle, Douglas Woodbridge of Surrey recorded the loss of his spinach and turnip crops. Several hectares of mature plants were ploughed into the fields while the remainder was sold locally as livestock fodder. He comments on the lack of incentives and support given to farmers in his district, particularly those experiencing difficulties holding or consigning their produce.

In more recent times, improved understanding of the physiology of fruit and vegetables has resulted in a range of storage and distribution procedures which can be applied to reduce the risk of substantial post harvest losses. Food technologists commonly refer to harvested fruit and vegetables as living structures. When described in this manner, we’re reminded that most produce continues metabolizing following detachment from parent stock.

Fresh vegetables absorb atmospheric oxygen and release carbon dioxide, water, and heat. Within individual cells the metabolic breakdown of stores containing starch, sugars and organic acids results in molecules of carbon dioxide and water. Once detached from parent stock, these progressive water losses cannot be replaced by the distribution of sap through interior vessels. In combination with the prevention of microbial and insect challenges, contemporary post harvest technologies usually aim to reduce the metabolic rate of stored produce. Several of these involve chemical substances or procedures incompatible with the environmental and health precautions of organic certification standards.

There are a variety of economical ways to store organic vegetables but the best approach will depend upon each particular variety and the season. The majority of root crops can be stored satisfactorily in cool locations which are well protected from sunlight. When grown in small quantities, root vegetables such as parsnip and turnip can be left in the ground until required. One traditional storage method which remains popular in some developing regions is the ventilated pit. Hard vegetables including potatoes, turnip, and yam are carefully piled inside pits carved beneath the elevated facades of terrace slopes, hillsides and other suitably drained locations. The interior is usually insulated with layers of straw then covered with dry sand or earth to protect the vegetables from frost and extreme weather conditions. Underground cellars were once widely popular as a practical means for securing below ground storage. The better examples provided ventilation openings which enabled the circulation and removal of excessive humidity.

Careful handling then storage will enhance the longevity and nutritional value of organic vegetables. Bacterial mould is more likely to develop on bruised and damaged vegetables, and can rapidly spread to affect others. For this reason, it’s important to inspect stored crops regularly and remove any that have started to decay. Optimum results depend upon selecting the highest quality vegetables and rejecting any which are bruised or blemished. Many of the microscopic organisms causing mould and other forms of decay are unable to penetrate intact exterior skin but will readily invade through swollen areas and cuts. The portion of skin surrounding the stem is a frequent point of entry for microorganisms. As a general rule the rate post harvest decay is decreased by low storage temperatures and humidity. The highly controlled environments designed for commercial storage may also restrict circulating oxygen and prevent natural ripening with chemical treatments.

Following a successful harvest, I make efforts to store my vegetable groups separately and always avoid storing any type of fruit with vegetables. A non-functioning refrigerator or chest freezer can make a useful storage vessel for garden fresh vegetables. They offer protection from light and the insulation helps to maintain relatively constant temperatures within. Adequate ventilation can be ensured by drilling small holes in the door or lid sealings. They are inaccessible to rodents so can be safely housed outdoors in dry sheds and other suitable buildings. Larger vegetables like pumpkin, marrow, corn, and potatoes can also be stored in clearly labeled wooden or plastic boxes. The red skinned and other pigmented potatoes are particularly long lasting and may be stored for up to one year. Well-ventilated containers will accommodate several layers when required. Since it is important to minimize contact during storage, each new layer should be separated from those below with sheets of corrugated cardboard or similar. Onions and garlic will also last a considerable time but need to be properly aired in string bags or hessian sacks.

Depending on their variety and physical condition, many organic vegetables will benefit from refrigerated or frozen storage. According to food experts there are few nutritional disadvantages associated with snap frozen vegetables or those correctly accommodated in refrigerated stores. Because vegetable varieties respond differently according to their physiology, it can sometimes be challenging to select refrigeration temperatures suitable for a range of seasonal and imported produce. Provided there’s no risk of cold injury, maximum storage life is usually obtained by approaching but not exceeding the freezing point of tissue. In vegetables not susceptible to cold injury, maximum storage life can be obtained by storage close to the freezing point of the tissue. By maintaining an even temperature around four degrees celcius the durability of leafy greens, peas, corn, and asparagus can be extended over several days despite fluctuations or extremes of local temperature. Given they’re in perfect condition, a wide range of organic vegetables can also be frozen for several months without losing their nutritional quality or flavors. To prevent scarring and discoloration, crisp fleshy vegetables like beans, cauliflower, and broccoli should be blanched in boiling water for sixty seconds before freezing.

Within a short period of time refrigerated cold storage may interfere with the overall quality and flavor of root and tuberous vegetables. Refrigeration tends to encourage the conversion of starches to sugar, resulting in vegetables with poor texture and less robust flavors. When stored at temperatures above fifteen degrees celcius, many potato varieties will exit their dormant stage and commence sprouting. This can usually be delayed by storage systems which avoid unnecessary light, humidity, and close proximity with other produce. Dependent on their codes of practice, some commercial distributors may apply chemicals or radiation to suppress sprouting in their potato consignments. Maleic hydrazide (MH), isopropyl-phenylcarbamate (IPPC), and methyl naphthaleneacetic (MENA), are all commercial sprout inhibitors. All of these chemicals are potentially harmful and remain subject to legal restrictions or total bans imposed by organic certifiers.

Just two blocks down from my daughter’s house there’s a small grocery store stocking an exclusive range of organically certified sweet relish, pickles, and salsas. I always purchase a few jars of their spicy vegetable pickle. It’s terrific for firing up a ploughman’s lunch. Before refrigeration, food preservation techniques were an essential component of household management. Given sufficient time, spare vegetables can still be transformed into a wide range of traditional and exotic accompaniments. Zucchinis, onion, carrot, beetroot, and many others can be gently simmered with vinegar, sugar and combinations of spices, apple, tomato, and raisins. When properly sealed in preserving jars, home made relish and chutneys store on the shelf for up to twelve months. From my experience, food preservation tends to encourage resourcefulness and reduces the potential for waste. Produce falling below a premium standard can also be processed into juices or purees then frozen for up to one month before being used in soups and other recipes.