Food Safety Problems in Outdoor Farming and Indoor Farming Suggested Solutions

Introduction
Vegetables and fruits are the most important dietary component in human nutrition. Legumes, rice, potatoes, bread made of wheat and other vegetables are the principal products of healthy nutrition recommendations all around the world. However, growth of the products faces wide range of different challenges. Plants are vulnerable to pests, are sensitive to weather conditions, require fertilizers as additional nutrients source, easily decay after harvesting. Before mentioned reasons create food safety issues which could affect human health. In this report, advantages of indoor farming will be presented as a solution to food safety problems caused by traditional farming.
Food safety issues
Crops grown outdoor suffer from the geological and meteorological events such as undesirable temperatures or rainfall amounts, droughts or floods (1). Crops losses due to drought and floods cost billions U.S. dollars every year (2) (3). Furthermore, climate change has a huge influence on crops yield. Regions have been proper for specific plant species, for example, cocoa are not suitable anymore because suffer from long lasting drought (4). Not stable food supply may cause food availability and utilization problems which even could lead to famine (5).
Constant intensive framing causes irreversible damage to the land. Nowadays agriculture is hardly possible without fertilizers because of soil erosion. Agrochemicals, particularly fertilizers, are used in almost every major farming system regardless of location (6). Outdoor grown plants are vulnerable to insect pests and microbial diseases. Vast amount of synthetic pesticides, herbicides, fungicides and similar substances are used to save plant from these diseases. Hence, pesticides are potentially toxic to humans and can have both acute and chronic health effects, depending on the quantity and ways in which a person is exposed (7). WHO task group indicates that there may be 1 million serious unintentional poisonings each year and about 80000 of deaths from pesticides poisoning (8). Moreover, pesticides have tendency to accumulate in human body. Especially in adipose tissue, liver, kidney (9). Pesticides residues in food is a serious food safety problem.
In developed countries more than 70% of population lives in urban area and this number keeps increasing during the years (10). This situation creates food transportation problem which is closely related to food safety and quality issues. Sometimes fruits or vegetables happen to be transported thousands of kilometers even to the different continent. Dramatic losses of vitamins and nutrients occur in fruits and vegetables during transportation. According to the research, conducted by National Technical University of Athens, vitamin C loss in vegetables during transportation and storage is 25-75%. Spinaches, beans, peas and okra were used for this experiment. Comparing the relative retentions of vitamin C, spinaches have the most prominent sensitivity (11).
In addition to the nutrients degradation problem microorganisms and bacteria decrease the shelf-life of plants. Decomposition is a part of natural biological cycle, however, in food industry it is not a desirable process. Research has shown that 30% of harvested crops are wasted due to spoilage and infestation (1). Fruits such as citrus, pear, apple, grapes suffer from grey mold (Botrytis cinerea), blue mold (Penicillium expansum, Penicillium italicum), and green mold (Penicillium digitatum, ) decay, Rhizopus rot (Rhizopus stolonifer). Digestion of mold produced mycotoxins leads to food poisoning with symptoms of nausea, stomach cramps and vomiting (12). Fruits and vegetables may be contaminated by pathogenic bacteria during harvesting, transportation or distribution process. Salmonella, Staphylococcus aureus, Vibrio parahaemolyticus, Clostridium botulinus, Bacillus cereus, Listeria monocytes hyperplasia usually infect the food and cause bacterial food poisoning (13).
Indoor farming benefits
Reason of all above mentioned problems is outdoor farming in distant rural area. One possible solution involves the construction of urban food production centers – indoor farming in controlled artificial environment (6). If this applied, then no crops would ever fail due to severe weather events (droughts, floods), long distance transportation problem would not be relevant any more and food poisoning caused by spoilage bacteria and mold would be greatly reduced (6). Significant advantage of indoor farming is a space saving vertical arrangement of growing chambers. This difference helps to increase the yield of crop per one square meter of area.
Conception of indoor farming includes soilless growing environment, artificial lightning system, humidity, temperature, and gas environment (O2, N2, CO2) control. Plants are completely separated from outside environment and grow in the best suitable conditions. Hydroponic plant growing method use mineral nutrient solution in a water solvent instead of soil. Roots of plant are immersed directly to the solution and receive all desirable nutrients such as nitrogen, phosphorus, potassium, magnesium and copper. The nutrients within this solution provide the same minerals and nutrients that plants would normally get from healthy soil, while avoiding the vulnerability to pests that inevitably occurs in outdoor farms (14).
Natural light could be replaced by high-pressure sodium (HPS) lamps, metal halide (MH) lamps, white fluorescent lamps or light-emitting diode (LED) (15). Plant require only narrow range of sunlight spectra. Mixture of red (600-700nm) and blue (400–500nm) light crucial for successful plant development could be completely mimicked by LED (16). Information about temperature, humidity and CO2 level in the system is detected by sensors. Signal is transmitted to the control computer and according to received information ventilation system initiates changes.
Sceptics of hydroponic system concern about plants taste properties and nutritional value. However, a study in 2000, published in the “Practical Hydroponics & Greenhouses” compared hydroponics to soil grown vegetables and found that hydroponic produce can be superior in nutrition and taste – but this relies on the nutrient content of the hydroponic solutions. High concentration nutrient solutions can ensure a better product than outdoor produced vegetable (17).
Case analysis
Plants are complicated system which converts inorganic compounds to organic compounds and oxygen using sunlight energy. Photoreceptors play an important role in the photosynthesis process. The pigment moiety of photoreceptors allows the receptor to extract from the incoming natural white light the specific information related to the intensity of the environmental light constraints. It is necessary to understand how photosynthetic processes could be modified in plants grown under artificial lighting. If lighting is too weak, photosynthesis cannot work efficiently and etiolation symptoms appear [5]. However, excessive light generates oxygen radicals and causes photoinhibition. Different light intensity can shift primary and secondary metabolism of plants. From the biological point of view, the main question about artificial lightning is related to ability to mimic natural light while avoiding the adverse influence. {Š}
As an example, analyze artificial lightning quality affect on red lettuce growth and phytochemical synthesis. Red lettuce naturally contains several phytochemicals: anthocyanins, xanthophylls, carotene, phenolic compounds, ascorbic acid which have positive impact on human health. Cool white fluorescent lamps were used as the main white light source and different intensity LEDs were used as supplemental lighting. Growth and concentration of key phytochemicals were quantified under different supplemental light qualities. After twenty two days of growth red lettuce were harvested and examined. Results demonstrated that supplemental Blue (peak at 476 nm) or UV-A (peak at 373 nm) could enhance anthocyanins accumulation, supplemental Blue (peak at 476 nm) also increased carotenoids concentration, supplemental Red could increase phenolics concentration while supplemental Far Red (peak at 734 nm) light could increase biomass, but result in lower phytochemical concentrations. This study confirms lightning influence on plant secondary metabolites production and opens a wide range of opportunities to use artificial growth chambers form safe functional food production (18).
Urban farming examples
The idea of indoor farming is not new. Urban farming companies are mostly established in USA but there are some in Japan too. Each company uses slightly different urban farming application. Freight Farms provide ready-made hydroponic farm inside shipping containers that use LED lights and drip irrigation. The company also created an app that allows customers to remotely track conditions inside the container. Endenworks company seeks to build rooftop aquaponic greenhouses that grow organic greens. SproutsIQ encourages people to grow their own food in small mobile in-office or in-home systems (19). More over, NASA uses hydroponic growth systems supplemented by LED lightning in ISS to provide fresh vegetables to astronauts (20).
Conclusion
To sum up, indoor faming in artificial environment conditions could solve food safety problems. Pesticides residues in plants problem is not relevant because there is no threat of pests in growth chambers. Crop would not be lost due to meteorological conditions (floods, droughts) because in safe and fully monitored environment plants can thrive. Nutrients and vitamins loss, plants decay during long distance transportation would not be significant problem anymore. Urban farming shorten supply chain, thus consumers could enjoy fresh and tasty food. Less food would be wasted due to post-harvest decay. In addition to that, control of growth conditions can be used to manipulate the plant metabolism to produce functionalized foods with higher nutritional value. All these advantages have a great potential to maintain food safety