- Broccoli is a member of the mustard family of plants and is closely related to Brussels sprouts, cabbage, cauliflower, kale, and kohlrabi.
- The U.S. is the 3rd largest producer of broccoli in the world, with California leading in U.S. production (90%).
- There is currently no method to mechanically harvest broccoli, so it is harvested by hand.
- Broccoli provides an excellent source of vitamin K, vitamin C, chromium, and folic acid.
- Phytonutrients are highly concentrated in broccoli, especially glucosinolates, which are under scientific investigation for their role in cancer prevention.
- Between 1998 and 2017, at least 25 broccoli-associated outbreaks were reported to CDC’s National Outbreak Reporting System (NORS), causing 371 illnesses, 9 hospitalizations, and no deaths.
- There have been multiple broccoli and broccoli product recalls due to potential contamination with Listeria monocytogenes.
Broccoli (scientific name: Brassica oleracea var botrytis) is a member of the Brassicaceae plant family, also known as the mustard family. Other familiar plants in the species Brassica oleracea include Brussels sprouts, cabbage, cauliflower, kale, and kohlrabi. Broccoli is a derivative of cabbage, and was selected for its edible, immature flower heads. The flower buds are green or purple, are picked before they open, and are eaten raw or cooked. Broccoli sprouts are also edible, consumed raw, and are a popular health food in the U.S.
There are two distinct forms of broccoli: sprouting broccoli, and heading broccoli. Heading broccoli is the form most commonly grown in the U.S. It is characterized by its branching cluster of green flower buds atop a thick, green flower stalk, with smaller clusters that arise like sprouts from the stem. The other form of broccoli is called sprouting broccoli and makes a dense, white curd similar to cauliflower.
Broccoli originated in the Mediterranean region where it has been cultivated since Roman times, but is a relatively new crop to the U.S. The first commercial broccoli crop grown in the U.S. was started in California in 1923, but broccoli did not become a significant commercial crop in the U.S. until after World War II.
The U.S. is the 3rd largest producer of broccoli in the world. According to the United States Department of Agriculture National Agricultural Statistics Service, the U.S. produced 2 billion pounds of broccoli with a value of over 800 million dollars, grown on 129,000 acres of land, in 2014. Most of the broccoli harvested in the U.S. (90%) is grown in California, and 15-20% of U.S.-produced broccoli is exported to Canada, Japan, and Taiwan.
Foodborne Outbreaks and Recalls
Between 1998 and 2017, at least 25 broccoli-associated outbreaks were reported to CDC’s National Outbreak Reporting System (NORS), causing 371 illnesses, 9 hospitalizations, and no deaths. In outbreaks with a known etiology, the most commonly implicated pathogen was norovirus (60%), but outbreaks implicating broccoli were also associated with Salmonella (13%), Bacillus cereus (7%), Campylobacter (7%), Clostridium botulinum (7%), Clostridium perfringens (7%), and chemical/toxin (7%). There have also been broccoli and broccoli product recalls without any reported illnesses. Such voluntary recalls have been due to potential contamination mainly with Listeria, but also Escherichia coli.
Below are examples of outbreaks and recalls associated with broccoli reflecting the diversity of vehicles, pathogens, and other circumstances:
In 2011, Taylor Farms Inc., of California, voluntarily recalled its multiple broccoli-containing products due to potential Listeria contamination. The recall was initiated after routine sampling of broccoli yielded Listeria. Recalled products included Raley’s brand yellow curry chicken rice bowls, udon pork noodle bowls, udon chicken noodle bowls, Asian pasta toss trays, family grilled chicken penne alfredo, and grilled chicken breast with mashed potato and gravy; Taylor Farms brand snack pot penne alfredo and broccoli crunch salad kits; and SYSCO brand broccoli crunch salad kits. There were no reported illnesses. The salad kits were not available to consumers, but instead unboxed and prepared by retailers for sale at deli counters and restaurants. The products were distributed in five states.
In 2013, Taylor Farms Inc., of Maryland and Texas, voluntarily recalled its broccoli crunch with bacon and dressing salad kits due to potential contamination with Listeria. The recall was initiated due to potential Listeria contamination of the salad dressing packets. The salad kits were not typically directly available to consumers, but instead unboxed and prepared by retailers for sale at deli counters and restaurants. The product was distributed in seven states. There were no reported illnesses.
In 2015, Greystone Foods, LLC voluntarily recalled its Today’s Harvest brand frozen broccoli florets due to potential contamination with Listeria. The recall was initiated after a supplier notified the company that a non-food contact surface in its facility tested positive for Listeria. The product was distributed to Publix Supermarkets in Florida. There were no reported illnesses.
In 2016, Butterfield Foods, Inc., of Indiana, voluntarily recalled its broccoli salad kits due to potential contamination with Listeria. The recall was initiated after a distributor, SunOpta, notified the company that its sunflower kernel products used in the salad dressing product were recalled due to possible contamination. There were no reported illnesses.
In 2017, Gold Coast Packing, Inc. voluntarily recalled its bagged broccoli florets due to potential contamination with Escherichia coli O26. The product was distributed to Costco Wholesale retailers in British Columbia, Canada. There were no reported illnesses.
In 2018, GIANT Food Stores, Inc., of Pennsylvania, voluntarily recalled its Private Brand frozen broccoli cuts due to potential Listeria contamination. The recall was initiated after a supplier notified the company of possible product contamination. The product was distributed in four states. There were no reported illnesses.
In 2018, Del Monte Fresh Produce prepackaged vegetable trays sickened 250 individuals (8 hospitalization; 0 deaths) with Cyclospora cayetanensis across 4 states. The trays contained broccoli, cauliflower, carrots, celery, and dill dip, and were distributed to multiple retailers. Investigators were unable to identify any individual component of the vegetable trays as the vehicle.
Food Production Level I
Broccoli is a cool-season vegetable and can be grown as a spring or fall crop. Seeds will germinate between 40-95°F but the optimal temperature for growth is 60-65°F, and it takes 75-140 days to grow to maturity. Broccoli is primarily planted in two ways, either by direct seeding or transplanting, with the majority of the industry using direct seeding. Seedlings that are transplanted can be started either in hotbeds or greenhouses. Broccoli is typically grown in double rows on raised beds. While it can grow in a wide range of soil types, for optimum growth the soil must be well-draining, moderately salt sensitive, nutrient dense, and have a pH between 6.0-6.5. Phosphorus and potassium may be added to the soil to meet nutrient demands. Irrigation is required to maximize yield, and is usually done with furrows and overhead sprinklers, though surface drip is also sometimes used. Weed control can be achieved with herbicides, mechanical control, and a good crop-rotation system. The most common broccoli pests include different types of caterpillars, which can be controlled using organic insecticides, synthetic insecticides, or by manually removing the worms (small crops only).
Food Production Level II
The majority of broccoli is harvested year round, during the warm season it is harvested on the Central Coast of California and during the cool season it is harvested in the desert regions of California. Broccoli is harvested for fresh consumption or processing, depending on many factors such as current market value. There is currently no method to mechanically harvest broccoli, so it is harvested by hand. Fresh market broccoli is field packed. Good-quality broccoli should have dark or bright green, closed flower buds, and the head should be compact, with a cleanly cut stalk of the required length. The standard pack consists of heads that average 3 to 8 inches in diameter. Field workers either cut or snap the stems at 8 inches and place the heads on a harvest-aid belt. Two to four heads are bunched, secured with a rubber band, and then cut to a uniform 7 inches. Fourteen or eighteen bunches of broccoli are packed in a waxed-fiberboard carton that weighs a minimum of 23 pounds. Crown-cut broccoli consists of a top dome 5 to 5.5 inches in diameter, cut from the stem at 5 inches. A packed carton consists of 34 to 38 bulk- packed crowns and weighs a minimum of 20 pounds. Field-cut florets are loosely packed in tote bags and packed into cardboard cartons that weigh 9 to 18 pounds and contain three to four bags each. Broccoli destined for the freezer is also hand-harvested. The stem is cut at 6 inches, slightly shorter than for fresh market. The heads are placed on belts, then collected into large bins or trailers, and hauled to the processor.
Food Production Level III
Once harvested, broccoli must be cooled rapidly to preserve shelf life. Liquid icing of the field packed cartons is common. The optimal storage temperature is 32°F, varying outside of this temperature could negatively affect shelf life. Broccoli is extremely sensitive to exposure to ethylene, and exposure to as little as 2ppm of ethylene can reduce shelf life by 50%. Once broccoli is field packaged, the cartons are filled with slushed ice for shipping. Optimal storage life for broccoli is 21-28 days.
Due to Federal Government dietary recommendations and increasing popularity, consumption and production of fresh produce in the U.S. have increased. However, fresh vegetables, such as broccoli, can serve as vehicles for pathogens that cause foodborne illness, including Salmonella, Shiga-toxin producing Escherichia coli, Shigella, hepatitis A virus, norovirus, and Cyclospora cayetanensis. Human infection occurs via the fecal-oral route and there are many points along the farm-to-fork continuum at which broccoli can become contaminated with human or animal feces, either directly or indirectly.
Fresh vegetables are often minimally processed, without a ‘kill step,’ and may be peeled, sliced, chopped, shredded, cored, or trimmed with or without washing, or other treatments, prior to being packaged for use by consumers. Fresh cut vegetables are at increased risk for microbial growth and contamination. The high moisture and nutrient content of fresh vegetables, absence of a ‘kill step’ during processing, and potential for temperature abuse at many points, including processing, storage, transport, and at retail, further increase this risk. Additionally, the high degree of handling of fresh vegetables during production and processing as well as the mixing of produce items that often occurs at processing operations provide opportunities for contamination and the possibility of contaminating a large volume of product.
Broccoli may become contaminated during production, via untreated manure, contaminated water, infected workers, presence of animals, unclean conditions in the field or packing facility, or during transportation. It is important to properly maintain and sanitize equipment and food contact surfaces throughout production and processing.
It is important for growers, packers, and shippers to follow the preventative measures included in Good Agricultural Practices (GAPs), Good Manufacturing Practices (GMPs), Good Handling Practices (GHPs), Sanitation Standard Operating Procedures (SSOPs), and the U.S. FDA’s “Guide to Minimize Microbial Food Safety Hazards of Fresh-cut Fruits and Vegetables” to help prevent microbial contamination. Due to the extensive handling of broccoli, food safety training for workers and following of proper sanitation and hygiene practices are crucial.
Consumers should follow the standard “clean, separate, cook, and chill” food safety practices when preparing broccoli. Broccoli should be stored, unwashed, in the refrigerator and consumed within 3-5 days. Broccoli should be washed with fresh, cold water prior to consumption or cooking.
Over the last 25 years, broccoli consumption has increased over 940%. The average annual per capita consumption of broccoli in the United States is 5.8 pounds.
For more information on the shelf life of broccoli, please visit the FoodKeeper App.
Broccoli provides an excellent source of vitamin K, vitamin C, chromium, and folic acid. It is a good source of dietary fiber, pantothenic acid, vitamin B6, vitamin E, manganese, phosphorus, choline, vitamin B1, Beta-carotene, potassium, and copper. Broccoli in the diet also supplies vitamin B1, magnesium, omega-3 fatty acids, protein, zinc, calcium, iron, niacin, and selenium. One cup of broccoli contains 54 calories, 0.64 grams of fat, provides 135% of the daily vitamin C requirement, and 245% of daily vitamin K requirement of a 2000-calorie per day diet. Vitamin C, vitamin E, lutein, and other antioxidants in broccoli are anti-inflammatory and prevent damage to the body caused by free radicals. Phytonutrients are highly concentrated in broccoli, especially glucosinolates, which are under scientific investigation for their role in cancer prevention. Recent studies have provided evidence that glucosinolates decrease the metastatic potential of lung cancer, prolong survival in patients with bladder cancer, and lower the risk of breast cancer.
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Externally Reviewed by: Richard Smith, MS Affiliation: University of California Cooperative Extension, Vegetable Crops and Weed Science Reviewed on: 9 February 2018