Impact of Environmental Factors on Post-harvest Losses of Fruits and Vegetables

Every year, a significant portion of harvested fruits and vegetables never reaches the consumer’s plate. While poor handling and inadequate storage facilities often get the blame, the story begins much earlier – in the field, where environmental conditions directly shape how well produce survives post-harvest. According to the FAO, losses of sweet potatoes, plantains, tomatoes, bananas, and citrus fruit in developing countries can sometimes reach as high as 50 percent. Understanding the environmental factors behind these losses is the first step toward reducing them.

How the environment shapes post-harvest outcomes 🔗

Research published in the Biomedical Journal of Scientific & Technical Research confirms that the freshness of fruits and vegetables after harvest is governed not just by internal biology but also by exogenous factors – including temperature, relative humidity, and atmospheric composition. What happens in the growing environment before harvest leaves a lasting imprint on shelf life and susceptibility to deterioration. NC State Extension explains that because fresh produce responds directly to environmental stimuli such as light, temperature, humidity, and surrounding atmospheric gases, controlling these conditions is essential to maintaining quality.

Effect of high temperatures and heat stress 🔗

High temperatures are among the most damaging environmental factors affecting produce quality. When crops are exposed to excessive heat during the growing season or at the time of harvest, they undergo accelerated physiological activity. Respiration rates rise, causing the produce to consume its own food and water reserves faster. Wikipedia’s article on post-harvest losses notes that high temperature, low atmospheric humidity, and physical injury are all factors that increase the rate at which a product’s food and water reserves are depleted, raising the likelihood of losses.

Heat stress also triggers premature ripening – a condition where fruits ripen unevenly or too quickly before they can be transported or sold. Once a fruit enters the ripening phase, it moves rapidly into senescence and breakdown. A ScienceDirect review on postharvest food loss identifies air temperature and relative humidity as the main underlying drivers of quality variation, over-ripening, and microbial decay throughout the supply chain.

Humidity and water loss 🔗

High temperatures rarely act alone – they typically combine with low humidity to accelerate water loss (transpiration) from harvested produce. Fresh produce continues losing water after harvest, causing shrinkage and weight loss. The rate of water loss depends on the ratio of the fruit or vegetable’s surface area to its volume. Leafy vegetables, which have thin skin with many pores, lose water far more quickly than potatoes, which have thick skin with few pores. Produce must be kept in a moist atmosphere to slow this process and extend shelf life.

Chilling injury: when cold storage goes wrong 🔗

While low temperatures are the primary tool for extending shelf life, applying cold storage incorrectly causes a well-documented problem: chilling injury (CI). A 2024 study in Frontiers in Plant Science defines chilling injury as physiological damage to cold-sensitive fruits and vegetables stored at temperatures above freezing but below their tolerance threshold – typically between 5-8°C for subtropical produce and below 12°C for tropical varieties.

At the cellular level, chilling injury disrupts membrane integrity, impairs hormone balance, damages photosynthetic function, and alters enzyme activity. The visible symptoms vary by crop. A Springer Nature review details that plums, bananas, and kiwifruit may exhibit peel browning; peaches, pears, and lychees may show flesh browning; and concave depressions may develop on green peppers, cucumbers, and citrus fruits. Water-soaked spots are common in tomatoes and cucumbers.

One of the most damaging consequences of chilling injury is that affected produce becomes highly susceptible to bacterial and fungal infections. Farm Progress reports that for tomatoes, chilling injury causes failure to ripen and develop full color and flavor, premature softening, surface pitting, browning of seeds, and increased decay – especially from black mold caused by Alternaria spp. Importantly, chilling injury is cumulative and may begin in the field before harvest even takes place.

Frost damage and freezing injury 🔗

Frost damage is a more severe and sudden form of cold stress. When field temperatures drop to or below 0°C, the water inside plant cells freezes, forming ice crystals that rupture cell walls. When the tissue thaws, the damage becomes visible as wilting, waterlogging, blackening, and eventual decay. All produce will freeze at temperatures between 0 and -2°C, and while a few commodities tolerate slight freezing, poor temperature control in storage leads to significant losses.

Crops like strawberries and lettuce are particularly vulnerable to frost. According to Farm Progress, asparagus shows freezing injury at -0.6°C or lower – spear tips become limp and dark, and thawed spears turn mushy. Artichokes exhibit blistering and bronzing of outer bracts with light frost, progressing to brown-to-black, gelatinous hearts under more severe conditions. The important distinction between frost damage and chilling injury is that frost damage results from ice formation within tissue, while chilling injury develops gradually at temperatures that remain above freezing.

Soil conditions and their post-harvest effect 🔗

Soil is not just where crops grow – it directly shapes the post-harvest performance of produce. ATTRA’s postharvest handling guide provides a useful illustration: carrots grown on muck soils do not hold up as well in storage as carrots grown on lighter, upland soils. Lettuce harvested during a period of rain does not ship well, and product losses increase significantly.

Soil fertility and moisture balance also matter. Waterlogging from excess rain or irrigation leads to decay and oxygen deprivation in root zones. Drought stress, caused by insufficient moisture, weakens plants and compromises their structural integrity after harvest. The FAO’s training manual on post-harvest losses further notes that poor crop husbandry – including uncontrolled weed growth and decaying plant residues left in the field – provides reservoirs of infection that directly contribute to post-harvest decay. Weeds also compete with crops for nutrients and soil moisture, further degrading produce quality before it even reaches the storage facility.

Soil nutritional imbalances add another layer of complexity. A PMC review on environmental conditions and nutritional quality found that suboptimal root zone temperatures hinder produce quality – and that soil temperature has measurable effects on vitamin C, soluble sugars, lycopene, and mineral content in vegetables like tomatoes.

Hail damage and physical injury 🔗

Hailstorms cause direct physical injuries to fruits and vegetables in the field. The impact of hailstones creates bruises, punctures, and surface abrasions that immediately compromise the protective outer layer of produce. These wounds act as entry points for pathogens. Research published in E3S Web of Conferences confirms that pathological rots are among the most common causes of post-harvest loss, and mechanical injury is a primary trigger. Apples damaged by hail, for example, may develop bacterial canker or fungal infections, reducing both shelf life and market value.

Physical damage from hail also accelerates water loss and increases respiration rate – both of which speed up the deterioration process. The combination of disrupted surface integrity and elevated physiological activity makes hail-damaged produce extremely difficult to store, even under otherwise optimal conditions.

Environmental pollutants: air and water 🔗

Pollution is an increasingly relevant environmental factor in post-harvest quality. Air pollutants – particularly ozone, sulfur dioxide, and nitrogen oxides – cause oxidative stress in growing plants, reducing nutritional quality and marketability before harvest. The University of Maryland Extension explains that ozone is absorbed through leaf pores, damaging cell membranes and causing cells to collapse. Symptoms include stippling (tiny white spots), bronzing, bleached dead areas, and premature yellowing – all of which reduce marketability and signal compromised tissue that is more prone to post-harvest deterioration.

The Ontario Ministry of Agriculture further notes that particulate matter such as cement dust deposited on vegetation can inhibit normal respiration and photosynthesis, and that accumulation of alkaline dusts in soil can raise pH to levels that are adverse to crop growth. Britannica also identifies ozone as a major air pollutant affecting field crops including spinach, tobacco, fruits, vegetables, and forest trees.

Water pollutants present a different but equally serious risk. Heavy metals and pesticide residues can accumulate in soil and be absorbed by crops, resulting in chemical contamination of produce. This not only poses health risks to consumers but also shortens shelf life by disrupting normal metabolic processes within the plant tissue. Airly’s review on air pollution and agriculture highlights that the main concern is the reduction of nutrient value in produce from polluted areas – pollutants absorbed into plant tissue react with nutrients, diminishing their quantity and quality.

Protective measures to reduce environment-linked losses 🔗

Understanding these environmental threats creates the foundation for targeted protective strategies. Several practical interventions can significantly reduce losses:

Cold chain management: Storing produce at crop-specific optimal temperatures is essential. As NC State Extension notes, strawberries and apples respond well to temperatures just above freezing, while tomatoes, peppers, and squash may suffer chilling injury at those same temperatures. A one-size-fits-all cold storage approach causes more harm than good.

Mulching and shade: Mulching regulates soil temperature and moisture, reducing heat stress and waterlogging risk. PMC research found that mulching with polyethylene film raised soil temperatures in controlled ways that increased vitamin C and sugar concentrations in tomatoes.

Netting and row covers: Physical barriers protect crops from hail, frost, and insect damage, reducing surface injury and secondary infections before harvest.

Drip irrigation: Efficient irrigation systems maintain optimal soil moisture and prevent water stress, which directly affects post-harvest firmness and shelf life.

Windbreaks and buffer zones: Planting trees or shrubs around crop areas reduces wind speed and provides a buffer against wind-borne pollutants and dust, protecting crop surfaces from contamination.

Integrated pest and field management: Keeping fields free of decaying plant residues – which serve as infection reservoirs – combined with proper crop rotation and biological controls, reduces the pathogen load that contributes to post-harvest rot.

Controlled atmosphere (CA) storage: Managing the levels of oxygen, carbon dioxide, and ethylene during storage delays ripening and extends shelf life. Biomedres.us identifies CA storage combined with refrigeration as one of the most important contributions to modern storage technology, retarding respiratory processes and delaying yellowing, softening, and other deteriorative changes.

What do you think? Given that chilling injury affects tropical and subtropical produce even in refrigerated storage, how should farmers and supply chain managers balance the need for cold storage with the risk of temperature-related damage? And as air and water pollution increasingly affect growing areas worldwide, what policy-level changes could help protect produce quality from field to shelf?

References

1. https://www.fao.org/4/t0073e/t0073e01.htm
2. https://biomedres.us/fulltexts/BJSTR.MS.ID.002448.php
3. https://content.ces.ncsu.edu/introduction-to-the-postharvest-engineering-for-fresh-fruits-and-vegetables/postharvest-engineering-1-introduction
4. https://en.wikipedia.org/wiki/Post-harvest_losses_(vegetables)
5. https://www.sciencedirect.com/science/article/pii/S2214289423000340
6. https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2024.1488666/full
7. https://link.springer.com/article/10.1007/s44281-025-00093-4
8. https://www.farmprogress.com/vegetables/symptoms-of-frost-freezing-and-chilling-injury-on-vegetables
9. https://ucanr.edu/?legacy-file=339682.pdf&legacy-file-path=sites%2FCentralSierraAg%2Ffiles%2F
10. https://pmc.ncbi.nlm.nih.gov/articles/PMC11838150/
11. https://www.e3s-conferences.org/articles/e3sconf/pdf/2024/07/e3sconf_star2024_00076.pdf
12. https://extension.umd.edu/resource/air-pollution-damage-vegetables
13. https://www.ontario.ca/page/effects-air-pollution-agricultural-crops
14. https://www.britannica.com/technology/agricultural-technology/The-effects-of-pollution
15. https://airly.org/en/air-pollution-and-agriculture-how-pollution-affects-crops-and-food-security/