- In 2011, the contamination of fresh, whole cantaloupes resulted in a multi-state outbreak of listeriosis and resulted in 147 illnesses and 33 deaths. An environmental assessment conducted after the outbreak concluded suggests that the combination of available nutrients on the rind, increased rind water activity, and insufficient cooling to remove field heat before cold storage created an ideal environment for the growth of Listeria
- The complex surface of cantaloupe makes it well-suited for harboring pathogens.
- Since 1998, cantaloupe has caused the most deathsof any food item associated with foodborne illness outbreaks, totaling 40 deaths from 1998—2017.
- Although Salmonellahas been the cause of most of the outbreaks (23) and illnesses (997 persons), Norovirus, Campylobacter, coli O157, Listeria, Shigella, and other pathogens have also been associated with cantaloupe.
- Cantaloupes are a low-calorie source of vitamin A (β-carotene), vitamin C, potassium, folic acid, iron, some dietary fiber, and calcium.
Cantaloupes (scientific name: Cucumis melo L. cantaloupe) are part of the Cucurbitaceae plant family and are also commonly referred to as muskmelon (Cucumis melo). However, these are different plants scientifically and have different characteristics. Cantaloupes are characterized by a hard, non-netted and rough-warty rind, while muskmelons are characterized by having a netted rind and thick orange flesh. There is only a very small number of true cantaloupes grown in the United States. Despite these differences, the U.S. Department of Agriculture only uses the term “cantaloupe” to describe both true cantaloupe and muskmelon.
There are many cantaloupe varieties, and growers select seeds based on their region’s soil type and weather conditions.
California is by far the largest producer of cantaloupe in the U.S., accounting for about 60% of the nation’s supply in 2018; Arizona is the second largest producer, accounting for 20% of the supply.
Colorado farmers have been growing cantaloupes, and primarily the “Netted Gem” variation, for market since the Burpee company cultivar was introduced in the early 1880s. Although there are several dozen farms growing cantaloupes across the state of Colorado, most are grown in the Rocky Ford region in the southeastern portion of the state. Landowner, politician, and entrepreneur, George Washington Swink, built the melon industry after he transformed this region by developing a canal-based irrigation system.
Many consider Rocky Ford cantaloupes to be some of the best. They are known for their quality and sweetness, which is the result of the seed used and the type of soil in the region—a sandy loam or clay-loam soil—as well as certain production practices used.
Colorado Cantaloupe Data
Despite the popularity of the Rocky Ford cantaloupe, Colorado only ranks eighth among states in production, accounting for less than 1% of the total acres harvested. Just under 85% of all Colorado cantaloupes are grown in the Southeast agricultural district, with the major contributing counties being Otero and Pueblo. The Northeast agricultural district of Boulder and Weld counties contribute almost 8% of the state’s production.
2017 Colorado planting data:
- Dates planted: April 15 to May 15
- Total acres harvested: 577
- Most active harvesting dates: August 10th—August 31st
- Days to market maturity after pollination: 40-50 days
In the United States, during the period between 1998 and 2018, cantaloupes were the fourth most common produce item to cause foodborne illness, after leafy greens, sprouts, and tomatoes (respectively), although cantaloupes were consumed in lower quantities.
Although over half of all cantaloupe outbreaks have been due to Salmonella contamination, there have also been issues related to Norovirus, Campylobacter, E. coli O157, Listeria, Shigella, and other pathogens.
Many cantaloupe outbreaks have been linked to imported fruit; however, the major, multistate listeriosis and salmonellosis outbreaks in 2011 and 2012 were associated with consumption of fresh cantaloupe from farms located in Colorado and Indiana, respectively.
Compared with other foodborne disease outbreaks, cantaloupe outbreaks have been more severe and widespread. Since 1999 there have been 1,732 illnesses, 367 hospitalizations, and 40 deaths.
The 2011 outbreak was the deadliest outbreak since 1924 and was the first listeriosis outbreak associated with melon. A total of 147 ill persons were reported, of which, 99% were hospitalized; 33 deaths were reported. Ages of ill persons ranged from less than 1 to 96 years of age (median 78 years old). Most ill persons were over 60 years old, and seven pregnancy-related illness (three newborns and four pregnant women) were reported, resulting in one miscarriage. The outbreak was unusual in that five widely differing pulse field gel electrophoresis (PFGE) pattern combinations and two serotypes (1/2a and 1/2b) were associated with the outbreak. Traceback investigation identified Jensen Farms in Holly, Colorado as the source of the contaminated cantaloupes. The method by which Listeria contaminated the cantaloupes at Jensen Farms remains unknown despite FDA investigations.
A year after the listeriosis outbreak, another multistate outbreak occurred infecting 261 people with both Salmonella Newport and Salmonella Typhimurium strains. Ill persons ranged from less than 1 to 100 years old (median 47 years old). 51% of those infected reported being hospitalized and 3 deaths occurred.
In February 2013, the director of the Center for Food Safety and Applied Nutrition at the FDA issued letters to members of the cantaloupe industry who grow, harvest, sort, pack, process, or ship cantaloupe, directing them to observe the existing best practices for food safety.
Cantaloupes were included in a 2018 Salmonella outbreak and recall of pre-cut melons and mixed fruit salads containing melon. This outbreak, which spanned from April to July of 2018 involved 9 states, resulting in 77 illnesses and 36 hospitalizations. Investigation into the outbreak linked the Salmonella Adelaide outbreak strain to pre-cut melon supplied by Caito Foods, which included pre-cut with cantaloupe, pre-cut watermelon, and pre-cut fruit mixes. Caito Food initiated a recall on June of 2018 as a result of illnesses reported in the area and reports made by state departments of public health.
Caito Foods was linked to additional outbreak of Salmonella Carrau the following year that occurred between March 2019 and May 2019. A total of 137 people were infected during the outbreak, leading to 38 hospitalization and no reported deaths. Traceback evidence revealed that pre-cut melon from Caito Foods was the source of the outbreak; Caito foods subsequently issued a recall on pre-cut watermelon, pre-cut cantaloupe, and fruit mixes containing melon as they had the previous year. In February 2020, Caito Foods announced it would be closing their fresh-cut food manufacturing operations due to loss of a major customer.
Worldwide, the United States is the 8th largest producer of cantaloupes/other melons. Nearly 14 million pounds of cantaloupes were produced in the U.S. in 2017, reaching a production value of over $260 million. However, both the harvested area and weight production of cantaloupe has decreased from 1992 to 2017—from 109,400 to 57,050 acres and 1.8 to 1.3 trillion pounds.
While the U.S. exported 179 million pounds, over 1.0 billion pounds of cantaloupe were imported in 2017. Most imported product comes from Guatemala, with Honduras, Mexico, and Costa Rica supplying a significant amount also.
In 2018, the states leading cantaloupe production by weight were California, Arizona, Indiana, North Carolina, Texas, and Pennsylvania, respectively. Over 80% of the nation’s cantaloupes were grown in California and Arizona.
Soil & Planting
Cantaloupes are warm-season annual plants that are sensitive to freezing temperatures at any growth stage. They grow best in sunny, hot weather, with minimal rain and low humidity, and they are typically planted in the spring after frost is no longer a concern.
Sandy soils are used for the earliest plantings because they warm more rapidly in the spring, while loam and clay loam soils are preferred for main-season production due to greater water-holding capacity, which favors a prolonged harvest period.
Most cantaloupes are direct seeded, in a single seed line per bed. Seeds are planted under 3 to 6 inches of loose, pre-irrigated, moist soil. It is important that the soil is well-drained to prevent root diseases.
Cantaloupes are often planted in raised beds, which helps irrigation water get to the roots while the melon remains dry. A lightweight plastic film or mulch is often used to cover a seedbed. See plasticulture for details.
In California, some growers use specialized techniques to promote earliness. In the southern desert valleys, cantaloupes are often grown in a mid-bed trench. This system uses a bed shaper to produce a trench in the center of an 80-inch bed. A single seed line is planted in the trench and then covered with clear polyethylene, which helps provide some frost protection and aids in early growth. After plants are established, they are thinned, the area is weeded, and the polyethylene is vented and removed. The beds are then reshaped into a standard configuration.
Slant-bed culture is also common, wherein a single seed row is planted on a south-facing side of a sloping 80-inch bed. This method increases solar heating and stimulates germination. These beds are also re-shaped after crop establishment into a standard 80-inch raised bed.
Cantaloupes produce both staminate and perfect flowers, the latter having both male and female parts and ultimately developing into the fruit.
Growing cantaloupes requires bee pollination. Poor weather conditions (cold, rain, high wind, or prolonged cloud coverage) or use of pesticides that reduce bee activity may reduce yield.
If cantaloupes contact moist soil during the growing period, a “ground spot” may result. This is an area on the rind that is thin, poorly developed, soft, and appears lighter in color. The presence of a ground spot increases the risk for microbial growth and pathogen contamination. In addition, cantaloupes with ground spot may be more susceptible to internalization by pathogens during post-harvest handling.
In some regions, growers will hand-turn melons to prevent development of a ground spot, increasing the potential for contamination from human contact. However, ground spot formation can be prevented using methods other than hand-turning to keep cantaloupes off of the ground and dry, including proper planting-bed preparation and careful irrigation management.
Although it is not common practice, some growers may use animal manure and/or composts as soil amendments.
To qualify for organic certification, growers of organic cantaloupes must comply with requirements for composted and certified soil amendments.
Cantaloupes need plentiful water, and frequency of irrigation can vary from weekly to daily. There is considerable variation depending on weather, irrigation efficiency, leaching requirements, and need for pre-irrigation.
The water used during production and harvesting activities may come from a variety of sources, including municipal water, wastewater, ponds, rivers, lakes, wells, etc.
Cantaloupe growers use a wide variety of irrigation methods to ensure soil is moist, especially prior to planting. One of the most popular and oldest methods is furrow irrigation, also known as surface or flood irrigation. Although historically, most cantaloupe fields have been furrowed, many other growers have used sprinkler irrigation.
A more “intensive” method, drip irrigation, has become more popular since the 1990’s, resulting in approximately 2,000 acres in Colorado being devoted to drip irrigation, 90% of which is used to grow high-value crops, such as cantaloupe, watermelon, and onions. Drip lines are usually buried in the center of the soil beds; the drip system is portable, and depending on the grower’s management scheme and crop rotation, the drip systems may be renovated each season or left in place for a number of years. Most cantaloupes in Colorado are now grown using a combination of drip irrigation and plasticulture.
Whichever irrigation technique is used, it is important to ensure the tops of the beds stay dry in order to minimize fruit contact with moist soil, as this can result in ground spot and fruit rot.
Preventing disease in cantaloupe plants
Certain cultivars can be susceptible to various fungi and viruses. Additionally, various weeds and insects may be problematic. To reduce risk of common disease problems, growers avoid planting cantaloupes immediately following other cucurbits or solanaceous crops (such as tomatoes, peppers, and eggplant) in the rotation for at least four years.
Some growers use pesticides and/or fungicide-treated seed. Others may apply fungicide or whitewash foliar applications to prevent sunscald of ripening melons. Typically, spray applications are terminated 1-2 weeks prior to harvest, except with certain approved materials to treat late-season leaf diseases.
While cantaloupe varieties have been selectively bred to have good efficacy of preventing powdery mildew, no cultivars exist that make the melon resistant to insects or nematodes. Insecticides are therefore widely used; Over 130% of all cantaloupe-growing acres were treated with an insecticide in 2010, suggesting that some areas are treated with multiple chemicals for pest protection.
Weeds can be a serious problem in cantaloupe cultivation, and growers use a variety of weed-control methods. Where fields are pre-irrigated and planted in moist soil, in-row weed control is primarily used. Synthetic mulches are known to help control weeds within a row, with black or clear plastic being the most common and effective. Even so, 40% of all cantaloupe-growing acres were treated with herbicides in 2010.
Typically, during thinning of the melon seedlings, most fields receive at least one hand-hoeing. Herbicide application following thinning is also common practice to help prevent weed growth throughout the season.
Harvesting, packing, and storage
Cantaloupes are harvested by hand, typically during what is known as the three-quarters to full-slip stage, when melons are mature/ripe, with a more golden appearance, when sugar levels are highest, and when the fruit begins to easily separate from the stem with a twist or pull. Over a 10–14 day period, fields are harvested 8 to 10 times. If pathogens are present during this time, they can become attached to the cantaloupe rind, particularly where the stem was removed (the stem scar).
Handling practices immediately following harvest differ by grower and farm location/region and may impact food safety.
Most generally, cantaloupes are harvested, packed, inspected, and graded in the field, then transported to storage facility maintained at 36-40°F before they are shipped. Some producers harvest the melons into field bins and move them directly into shipping boxes once in the packing house.
In other cases, they are harvested into field boxes, plastic bins, in trailers, or onto a conveyor belt machine, ultimately to be taken to shed packing houses or other central packing facilities where they are packed in cartons or crates.
In the latter scenario, before the melons get packed and taken to cooling facilities, they are cleaned with brushes, either while dry or after they are hydrocooled through immersion in a dump tank or by spraying with water (and in some cases disinfectant-treated water). Some producers may take other steps to remove soil or other contaminants from the surface of the melons to prevent mold development.
Cantaloupes are sized either mechanically or by sight and generally packed in 40-pound cartons prior to shipment. Palletized cartons are shipped primarily by truck to terminal markets and wholesale receivers across the United States and Canada and are typically stored at 36°F to 40°F prior to shipment.
In order to maximize the fruit’s postharvest life, rapid removal of field heat is necessary. Forced air (pressure) cooling is the most common method used. Once properly cooled, cantaloupes can be stored for two weeks or more at temperatures between 34–40°F.
For more information regarding the production and distribution of Cantaloupes please visit the Produce Point of Origin Database.
Unfortunately, the physical characteristics of their rind and flesh make cantaloupes susceptible to pathogen contamination and growth. Cantaloupe consumption has been associated with many outbreaks in the last few decades, with 43 reported from 1998–2018.
As contamination can arise from soil, water, equipment, animals, or humans, and can occur at any phase of production (growth, harvesting, post-harvest handling, packing, transportation, or distribution), it is important to understand the details of each. Also, production methods may vary considerably between growers or by region.
Recommendations for safe consumer handling of cantaloupe are to use the product soon after purchase and wash the outside rind thoroughly under cold, clean running water, scrubbing with a clean vegetable brush to help remove soil or possible contamination before cutting. A clean knife and cutting board should be used. Cut melon should be stored at refrigerator temperature (41°F) or below and used within seven days. If the cut melon is kept above 41°F, it must be discarded after 4 hours.
Over the past 40 years, global trade providing fruit year-round and healthy-eating initiatives have increased the consumption of fresh produce in America. Melon consumption has also increased with the introduction of sweeter seedless and hybrid varieties. Cantaloupe, like most melons, is typically sliced and served with the rind on or removed from the rind.
Since 2003, cantaloupe consumption has been steadily decreasing, dropping from 10.8 pound to 8.7 pounds per capita in 2018. In that same year, Americans ate an average of 27 pounds of melons (including watermelon, honeydew, and others). While cantaloupe consumption has decreased, it is still high in comparison to other melons and in 2017 was the 2nd most commonly consumed melon, only behind watermelon.
Recent marketing attempts have been targeted at smaller households and the single-serving market and have been focused on pre-cut cantaloupe displays and in-store salad bars.
More information on how to keep cantaloupe stored properly please visit FoodKeeper App.
Cantaloupes are a low-calorie (27 calories per 1/2 cup serving), nutrient-dense fruit. They are a rich source of vitamin A (β-carotene), vitamin C, potassium, folic acid, and the micronutrients copper, iron, and zinc. Cantaloupe is naturally low in sodium and contains some dietary fiber and calcium.
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Externally Reviewed by: Mike Bartolo, PhD Affiliation: CSU Department of Horticulture and Landscape Architecture, Vegetable Crop Senior Research Scientist and Extension Specialist Reviewed on: 3 November 2015