When is an avocado ready

Shelf Talk

Buttery rich and healthy, avocados are available year-round and delicious in everything from salads and burgers to the perennial favorite, guacamole.

At the supermarket, look for avocados with firm skin and no soft spots. Once you’re home, follow these simple steps for enjoying the maximum taste and shelf life from your avocados:

(1) Store avocados at room temperature until they’re fully ripe.

You can tell if an avocado is ripe by giving it a gentle squeeze — if it yields to that light pressure, it’s ready to use.

Store unripe avocados at room temperature. It generally takes anywhere from four to seven days for a hard avocado to fully ripen.

(2) Running out of time? Speed up the ripening process.

You can speed up the ripening process by putting your avocados in a brown paper bag — placing an apple in the bag will help hurry things along even more. This will usually cut down the ripening time to 1 to 3 days.

(3) Store fully ripe avocados in the refrigerator.

If you’ve got fully ripe avocados that you do not want to use right away, place them in the fridge in a plastic bag. There, they’ll usually keep well for another three to five days.

(4) Keep cut-up avocados tightly wrapped.

To keep cut-up avocado from turning brown, wrap it tightly in plastic wrap before refrigerating — sprinkling a small amount of lemon or lime juice onto the exposed avocado flesh will also help prevent discoloration.

(5) Stash leftovers in the freezer.

Avocados freeze very well, with just a little bit of extra preparation. To freeze: Wash, peel and then puree the avocados. Add to the puree 1/2 tablespoon of lemon juice for every avocado used to prevent browning. Place the puree in covered airtight containers or heavy-duty freezer bags and use within six months for best quality.

How to Tell When an Avocado Is Ripe on the Tree

If there was any fruit that identified most with Southern California, that icon of buttery goodness would be the avocado.

And out there, the king of avocados is the Hass. Once an obscure cultivar, it now accounts for 80 percent of the world’s avocado crop and 90 percent of California’s avocado crop, where San Diego leads the way with the highest number of orchards.

Its namesake, Rudolph Hass, was a US Postal Service carrier and a hobby horticulturist living in La Habra Heights, California. In 1926, Hass purchased seeds from a fellow avocado enthusiast and planted them in his fledgling avocado grove.

The subspecies of the seeds was never known, but many believe they came from a Guatemalan hybrid that had already been cross-pollinated by the time Hass bought them.

Only one seedling survived out of those seeds, and after many failed attempts to graft the seedling with branches from Fuerte avocado trees (the industry standard at the time), Hass decided to leave his little tree be… after being convinced not to cut it down in favor of his more reliable cultivars.

When the tree began bearing odd, bumpy fruit, Hass and his family sold what they couldn’t eat to co-workers at the post office and to the Model Grocery Store in Pasadena. The superior flavor and high demand firmly put the Hass avocado in its place as a luxury fruit, selling for $1 each (equivalent to today’s adjusted cost of $15… can you imagine paying over $30 for a bowl of guacamole these days?!).

Hass patented his tree in 1935 (the first U.S. patent ever granted for a tree) and contracted with a local grower, Harold Brokaw, to produce grafted seedlings from the cuttings of this tree. The Hass avocado grew quicker, yielded more, lasted longer, and tasted better than the Fuerte avocado, eventually becoming the Big Kahuna in the commercial avocado market by the 1970s.

From that single mama tree that Rudolph Hass started from seed, comes every single Hass avocado tree that exists in the world today. Just imagine the first cuttings that Brokaw took, spawning generations of cuttings over the course of 80 years, all propagated from that one tree. How trippy is that?

The mama tree lived on in suburbia after Hass’ death in 1952 and was cared for by Brokaw’s nephew until its own demise in 2002. The tree struggled with root fungus for more than a decade and was eventually cut down. Two plaques commemorate the spot where it grew near a private residence at 426 West Road in La Habra Heights, California (should you find yourself in the neighborhood and want to wow yourself with a piece of agricultural history).

If you live in California and have an avocado tree in your yard, chances are it’s a Hass (though if you have a very mature tree, like I did, it could easily be one of the seven other varieties grown in this state). And chances are, it’s just dripping with fruit right about now, and you’re wondering when they’ll start to soften.

Don’t make my mistake the first year I moved into my house, and just wait… and wait… and wait… until my avocados started dropping to the ground one by one, over-mature. And definitely don’t pick them before their prime, else you’ll just cut into a piece of rubber that even tastes like rubber (yes, I’ve tried).

So how can you tell when an avocado is ripe on the tree? The short answer is, you can’t.

I know, not very helpful. But wait!

The long answer is, avocados do not ripen on trees. This goes for all varieties, but since there are over 900 of them out there (and 8 that specifically grow in California), I’ll focus on the Hass.

Avocados are unique in that they ripen once they’re off the tree. That means that if you’re not ready to harvest them all yet, the best place to store your avocados is on the tree.

The Hass variety is known for being an exceptional keeper, maturing in winter and continuing to develop its flavor through summer. (Californians are incredibly lucky to have avocados year-round because of this, and in great, cheap abundance!)

Hass avocados start as smooth, bright green fruit. As they mature, their skin turns increasingly pebbly and purplish-black. The longer the fruit is left on the tree, the higher the oil content and richer the flavor it will develop. But leave it for too long, and the oil inside the avocado will turn rancid and the fruit will naturally fall from the tree (at which point it’s no longer good).

Harvest typically begins in February and goes as late as September. The tricky part is that even among the Hass cultivar, many factors can affect the maturity rate of the fruit, including climate (was it uncharacteristically warm that year — or cold?), soil (was it under-fertilized or over-fertilized?), and even bearing pattern (low yields and late maturity one year — usually due to cold — may result in high yields and early maturity the next year).

The best way to tell whether your fruit is ready for harvest is to pick one nice, large, dark avocado from your tree, and then leave it out on the counter at room temperature. At this point, the thing is rock hard. You can practically use it as a pestle for your mortar, or even a weapon for self-defense. Have you ever dropped an unripe avocado on your toes? Oy, it’s not pleasant.

If the fruit softens evenly within a week or two, then the rest of your avocados are good for the pickin’. If the fruit turns rubbery or shrivels up, then it isn’t quite ready yet. Keep checking every couple of weeks by picking one fruit at a time until you find an avocado that ripens to the right consistency and flavor of your liking.

You can speed up the ripening process by placing your avocados in a paper bag, which helps them ripen sooner by trapping the natural off-gas that they generate (an active plant hormone called ethylene).

Avocados are climacteric fruits — right up there with apples and bananas — meaning they start to ripen off the tree through a process of ethylene production, which occurs when starch converts to sugar. This stage of climacteric signals the peak of ripeness for an avocado.

If you want to speed it up even more, you can stick an apple or banana inside the bag (or any other ethylene-producing fruit, such as peppers, peaches, tomatoes… whatever you have on hand).

The “gas chamber” created from having all these fruits emitting ethylene together will ensure your avocados ripen in just a few short days. The skin will turn darker (almost black) and become bumpier.

To check for softness, feel the fruit around the base of the stem — there should be a slight give. I also like to wrap my whole hand around the fruit and feel for a uniform suppleness. Avoid feeling up the fruit with your thumb, as the pressure can leave ugly brown spots on the flesh. You can also tell an avocado is ripe if its stem pulls off easily.

A perfectly ripe California avocado is rich and nutty… creamy and velvety… practically melting in your mouth. It’s a pure and simple slice of California gold!

Florida’s avocado season is gearing up, and though the industry has faced its share of challenges, it expects 2019’s volumes to be on par with a typical year, says Brooks Tropicals.

Peter Leifermann, vice president of sales and marketing, elaborates: “Overall acreage is down here – due to development and some grove loss to the Laurel Wilt virus – but our overall industry estimates are comparable with a typical year.”

This is a positive change from the previous two years’ crops, which suffered damages caused by Hurricane Irma.

“After our 2017 season was cut short by Hurricane Irma, and 2018 was a regenerative year for the trees, we’re happy to be heading into a more normal season, with promotional volume this summer,” he comments.

Meanwhile, growing conditions this season have been closer to ideal, he says.

“We had a pretty mild winter, with no real frost scares. But so far it has been a dry spring. And no hurricane in over 18 months!”

He notes that Florida avocados are seeing some harvesting delays, though. Growers were only able to harvest about 25% of early estimates last week.

Still, he says: “We should be on track within 10 days”.

SlimCado’s success

According to Leifermann, Brooks Tropicals’ SlimCado avocado has become both successful and easily recognized by consumers.

“There are many people who only know a tropical, green-skinned avocado as a SlimCado,” he comments.

The category’s name aims to refer to the Florida avocado’s lower caloric and fat content. However, he points out: “SlimCadoes are anything but slim”. In fact, “they’re huge compared to anything else out there.”

He notes the variety’s size sets it apart from another category that has performed well in the market – Hass.

“The average Hass weighs less than ¾ of a pound, while our fruit averages over 1¼ pound per fruit,” he explains.

Still, he emphasizes: “We do not necessarily view the Hass variety as always a competitor. The two varieties complement each other, offering consumers the perfect options depending on their needs.”

Commenting on market conditions, Leifermann says: “The market has been steady now for about a month due to lower volume from our Dominican groves, but we see promotable volume coming in July.”

Teach a man his avocado varieties and he’ll make fresh guacamole for a lifetime.

When the early Spanish explorers first set stepped into the jungles of the Caribbean and Central America, among the many novelties they found was a large green tree fruit, with leathery skin, a seed like a chestnut and creamy, lime-green flesh unlike anything they knew in their own heritage of edible plants. For the Spaniards, it was easy to see why the local people, from Mexico to Colombia, made use of this fatty, flavorful resource — and so the avocado was destined to become a superstar of fruits. It had been a dietary staple for thousands of years in the Americas, and now it would spread through the rest of the world: In 1750, the avocado was introduced to Indonesia, in 1833 Florida, in 1908 Israel. It reached Australia in the late 1800s.

The species arrived in California in 1856, and today orchards near San Diego, Los Angeles and Santa Barbara produce almost 90 percent of America’s avocados. The rich and creamy Hass variety makes up the vast majority of the production, while a few small farms grow a variety of rarities — like Reed, Fuerte, Zutano and Bacon (yes, bacon!). Meanwhile, Florida’s small industry is focused on varieties like Choquette, Hall and Lulu — large, smooth-skinned fruits with juicy, sweet flesh popular among populations of Caribbean immigrants. One company, Brooks Tropicals, is even marketing these low-oil varieties as “SlimCados.” Many Florida avocado lovers, in fact, dislike the California-grown varieties, sometimes describing them as “oily.” Californians, though, may backpedal from the taste and texture of the low-fat Florida avocados — and call them “watery.”

Ouch.

To see for ourselves the diverse range of avocados and each one’s culinary virtues, we lined up several varieties of the fruit (assembled with the kind help of the Santa Barbara-based avocado company Shade Farm Management), wielded our spoons and discovered that one avocado may not be better than another; each is simply different. For the diversity in shape, size, taste and texture in available varieties made it seem, sometimes, like we weren’t so much comparing types of avocados, but the proverbial apples and oranges.

Shepard. This small avocado, an important commercial variety in Australia, has delicate smooth skin and a pointed, acorn-shaped pit embedded in rich, sticky flesh. A relative of the Hass, it has its obvious similarities in texture, but with a thicker — almost gluey — consistency. It was a top contender in our lineup. Season*: August through October.

Choquette. A popular Florida variety, the Choquette avocado may easily weigh two pounds (the average Hass is perhaps 6 ounces). But, more so than in many other varieties, the Choquette’s weight is largely comprised of water. That is, cut this fruit with a knife and it bleeds lime-green juice. One of our panel described its taste as “avocado rainwater.” The flesh is silken and the flavor extremely mild. Season: October through December.

Tonnage. A classic avocado on the outside, with a pear-shaped figure and frog-green pebbly skin and a slender neck leading to the stem, the Tonnage stands out when tasted — for it is remarkably sweet. While its oil content is on the low side — just 8- to 10-percent fat — it is nonetheless buttery, with a faint and savory taste of chestnut. Season: September.

Daily 11. A huge avocado and a relative of the fatty Hass, the Daly 11 may weigh five pounds or more and bears a thick, armor-like hide with dense, flavorful, oily flesh inside. Season: August through October.

Macarthur. This voluptuously shaped variety, with a bulbous bottom that curves deeply into the stem, has thick and creamy meat, with a nutty flavor, and is decadently smooth and buttery when fully ripe. Delicious. Season: August through November.

Hall. A relative of the Choquette and similar in shape and size, the Hall avocado has nuttier, drier and thicker flesh, though still juicy and fruity. Season: October through November.

Mexicola Grande: Small but beautiful, the Mexicola Grande has glistening black skin, almost as thin as paper. The light-flavored flesh is slightly fibrous, sweet and juicy. Season: August through October.

Anaheim. This large and softball-shaped avocado may grow to two pounds and has buttery, creamy, soft flesh and a mild, nutty flavor. Season: June through September.

Hass. High-fat flesh, a nutty taste, and almond butter texture make the Hass both the classic West Coast avocado and a favorite worldwide. Its oil content can be 20 percent or higher, and its skin is tough and durable — ideal for shipping, and for use as a scooping cup when preparing Super Bowl guacamole. Season: Year-round.

Other U.S. grown avocado varieties available: Bacon, Fuerte, Zutano, Pinkerton, Gwen, Lamb Hass, Reed.

*Seasons described for Northern Hemisphere.

The four most popular avocado recipes on Food Republic:

  • Lobster Guacamole Recipe
  • Avocado Cream Pasta Sauce Recipe
  • Grilled Avocado With Quinoa Salad Recipe
  • Best Basic Guacamole Recipe
  • Avocados: June through January
  • Bananas: August through October
  • Basil: March through November
  • Blueberries: April through June
  • Broccoli: October through May
  • Broccoli raab: October through May
  • Brussels sprouts: November through March
  • Cabbage: November through June
  • Cantaloupes: March through July
  • Carrots: November through June
  • Cauliflower: November through May
  • Celeriac/celery root: November through June
  • Celery: November through June
  • Cilantro: November through May
  • Chard: November through May
  • Chiles: August through June
  • Coconuts: harvested year-round
  • Collard greens: November through May
  • Corn: August through June
  • Cucumbers: October through June
  • Eggplant: September through June
  • Dragon fruits: June through November
  • Fava beans: March through June
  • Fennel: September through June
  • Grapefruit: September through June
  • Grapes: August and September
  • Green beans: harvested year-round
  • Green onions: harvested year-round
  • Jackfruit: May through November
  • Kale: November through May
  • Guava: harvested year-round
  • Leeks: harvested year-round
  • Lemongrass: September through May
  • Lettuce: November through May
  • Limes: harvested year-round
  • Lychee: July and August
  • Mandarins: October through June
  • Mangoes: May through September
  • Melons: March through July
  • Mushrooms: (cultivated), year-round
  • Okra: August through January
  • Onions: harvested year-round
  • Oranges (navel): October through May
  • Oranges (valencia): January through August
  • Oregano: year-round
  • Papaya: harvested year-round
  • Parsley: year-round
  • Passion fruit: July through March
  • Pea greens: January through April
  • Peanuts: May through December
  • Peas and pea pods: January through May
  • Peppers (sweet): October through July
  • Pommelos: December through April
  • Potatoes: January through July
  • Pumpkins: fall
  • Quinces: fall
  • Radishes: October through June
  • Raspberries: summer
  • Scallions: harvested year-round
  • Shelling beans: August through November
  • Spinach: February and March
  • Squash (summer): September through June
  • Strawberries: October through June
  • Tangerines: September through May
  • Thyme: year-round
  • Tomatillos: September through June
  • Tomatoes: September through June
  • Watermelons: April through July
  • Zucchini: September through June

Experience Miami on a Food Tour

Hi I’m Julian Lara with the Tropical Fruit Growers South Florida; we’re an association of farmers that specialize in growing tropical fruits.

Now you can find these tropical fruits in the supermarket or at our website www.tropicalfrtuitgrowers.com. We’re in The Redlands, an agricultural area 25 miles southwest to Miami, Florida and we’re going to take a look at these avocados.

Avocados are native to Mexico and they’ve been around for thousands of years, and now they grow well all around the world in tropical and subtropical regions and they’ve been recorded here in South Florida in 1833 for the first time and they’ve been available commercially in the early nineteen hundreds.

We have so many varieties of avocado here in South Florida that we almost have them all year round. As you can see right here we have a Russell avocado, it has a much smoother skin than the ones you see in supermarkets that are from California or central America, they’re a lot larger and lower in fat and cholesterol and they’re very delicious.

Our farmers pick these avocados by hand when they are mature and they will either ripen at the supermarket or in your kitchen table… so why don’t we go to the kitchen and cut one of these up.

Now we’re back from the grove and we have our avocados. These are mature ones, these take about 2 to 5 days to ripen and when you get them from our growers they look like this, but when you go to the market make sure you don’t pick any avocados from the bunch that have any blemishes or soft spots.

When they’re ripe they look like this, they’re lighter in color and they yield to slight pressure. If you want your avocados to ripen faster here’s an old trick my grandma taught me: you get your mature avocado, put it in a paper bag, you get a tomato and put it in the bag with the avocado and the ethylene gas from the tomato will make the avocado ripen faster.

To open your avocado pierce the skin with a knife until you hit the seed, go kind of slow so you don’t slip, then cut around the seed, turn the halves in opposite directions so you can remove the seed. Slice a piece off the avocado, peel the skin back and dice it up.

For storing avocado what you got to do is let it ripen on the counter, do not put it in the refrigerator because it won’t ripen. So once it’s ripen on the counter, like this one, you can put it whole in the refrigerator and if you want it to last longer, because these will only last a couple of days in the refrigerator when it’s whole, so you have to slice it up or dice it up and put some lime juice to keep it from browning and it will last about a week. If you want it for longer you can mash this up into a puree, put it in a plastic container and put it in the freezer with some lime juice and it’ll last about six months.

As you can see avocados are very large, this one weighs about 3 pounds and they can weigh up to 4. Avocados are very rich in vitamins E and are used in many different ways, they can be eaten fresh with a little bit of salt or you can dice them up into salads, make some guacamole, slice them up for some sandwiches, or in other countries they use them for milkshakes and for ice-cream. So as you can see avocados have a lot of uses and if you want to order some of our fresh avocados go to our website www.tropicalfruitgrowers.com find one of our growers, have it delivered to your house and also look for some cool recipes on the avocado.

A food production wiki for public health professionals

Key Facts

Hass avocados hanging on a tree. Photo by Department of Agriculture and Food, Government of Western Australi

  • Avocado trees are native to the humid, sub-tropical and tropical regions of central and northern South America. They never go dormant.
  • Nearly 90% of avocado production in the United States takes place in California.
  • Avocados are harvested by hand and start to ripen once they are picked from the tree.
  • Commercial food safety practices for avocados have recently been strengthened due to the Food and Drug Administration’s (FDA) microbiological surveillance sampling of avocados and select avocado products.
  • Between 1998 and 2017, at least 8 avocado-associated outbreaks were reported to CDC’s National Outbreak Reporting System (NORS), causing 156 illnesses, 7 hospitalizations, and no deaths.
  • Pathogens associated with avocado outbreaks and recalls include Salmonella and Listeria monocytogenes.

Introduction

The avocado tree (Persea americana) is a tropical evergreen tree with three horticultural races: Guatemalan, Mexican, and West Indian. Trees can reach up to 60 feet (18 meters) tall and grow throughout the year; they do not enter a dormant state. The timing and length for each crop cycle depends mostly on temperature so crop development dates vary by location and from year to year.

Florida avocado (left) and Hass avocado (right). Photo by: thegardeningcook.com

The avocado was first domesticated in the United States by Henry Perrine in 1833 in Florida. There are more than 56 types of Florida avocados which are classified into three categories: summer, fall, and winter. The summer fruit has a bright green, smooth, thin skin whereas the fall and winter varieties are also bright green but have thicker, rough textured skins. The Hass avocado was discovered in La Habra Heights, California in the 1920s by Rudolph Hass. At first, the Hass avocado was not widely accepted among consumers because of its dark skin color. However, it is now the most widely-consumed type of avocado produced in the U.S. In 1957, Hass avocados only comprised 15% of the total crop yield. By the end of the 2010-2011 crop years, Hass avocados comprised 94.5% of the avocados commercially grown in California.

Avocados come in a variety of shapes, sizes, and colors. They can be shaped like a ball, a teardrop, or a football. Depending on the variety, the interior flesh ranges from bright yellow to yellow-green to pale yellow. Although the shapes and colors vary, all avocados have a smooth, creamy flesh and a delicate nutty flavor.

Foodborne Outbreaks and Recalls

Between 1998 and 2017, at least 8 avocado-associated outbreaks were reported to CDC’s National Outbreak Reporting System (NORS), causing 156 illnesses, 7 hospitalizations, and no deaths. In outbreaks with known etiology, the most commonly implicated pathogens were Salmonella (50%) and norovirus (33%), but have also included Bacillus cereus (17%).

There have also been avocado and avocado product recalls without any reported illnesses. Such voluntary recalls have been due to potential contamination with Salmonella and Listeria.

Below are examples of outbreaks and recalls associated with avocados reflecting the diversity of vehicles, pathogens, and other circumstances:

In 2010, J. Hellman Frozen Foods Inc. of California voluntarily recalled their Mexicano brand Avocado Pulp after random testing by the FDA yielded Listeria monocytogenes. There were no reported illnesses.

In 2011, Fine Mexican Food Products of California voluntarily recalled their frozen avocado pulp and IQF avocado halves after avocado pulp that had been manufactured in the same facility in Peru tested positive for Listeria monocytogenes. There were no reported illnesses.

Señor Mexicano™ Avocado Pulp recalled due to possible health risk. Photo by: U.S. Food and Drug Administration

In 2011, Fresh Food Concepts, Inc. of California voluntarily recalled their Layer Dip products after testing by the FDA revealed that the imported avocado pulp used in the dips contained Listeria monocytogenes. There were no reported illnesses.

In 2014, Latin Specialties, Inc. of Houston voluntarily recalled their whole avocados after testing by the FDA yielded Salmonella. The avocados originated from Unity Groves Corp. of Florida, but had gone through multiple entities, including Fresh King, before receipt by Latin Specialties, Inc. There were no reported illnesses.

In 2019, Henry Avocado Corporation voluntarily recalled their California-grown conventional and organic whole avocados after environmental samples tested positive for Listeria monocytogenes during routine inspection. There were no reported illnesses.

In 2019, Nature’s Touch Frozen Foods (West) Inc. voluntarily recalled their Signature Select brand frozen avocado chunks after routine product sampling by the FDA yielded Listeria monocytogenes. There were no reported illnesses.

Production

The United States is the second largest producer of avocados after Mexico. About 90% of avocado production in the United States takes place in California by more than 5,000 growers. The average grove size in California is about 13 acres. One avocado tree can produce from 200 to 500 avocados per year. About 400 million pounds of avocados are harvested each year in California alone. Florida and Hawaii produce most of the remaining 10% of avocados produced in the United States. In Florida, there are over 6,500 production acres in Miami-Dade County and a small amount of acreage in Collier County, where the climate is conducive to cultivating tropical fruits. Dooryard avocado trees make up an estimated 10% of the canopy in Miami-Dade County. The avocado industry in Florida is estimated to produce more than $55 million annually and supports over 1,000 full-time and part-time jobs.

Worldwide avocado production has dramatically increased from 4.6 billion pounds in 1994 to 6.8 billion pounds in 2004.

Pre-Harvest

In Florida, the common practice is to plant 87 trees per acre (planted 20 feet apart), but newer orchards are increasing the density to 100 trees per acre (planted 18 feet apart). New orchards are usually planted on existing agricultural land that was previously used for agricultural production. The sandy and limestone soils can produce satisfactory yields, ranging between 11,000 and 19,500 pounds per acre.

Avocados Groves in San Diego, North County, CA. May 19, 2016 |Photo by Jamie Scott Lytle

Avocado trees do not require extensive pruning, especially in their younger years. Most pruning takes place every other year and involves removing dead branches from the top of the canopy and maintaining desired width. Trees are kept at or below 20 feet high so they do not topple over from high winds.

Avocado trees to do not search for water, as their roots are shallow in the soil. The top layers of the soil can dry out quickly, and trees do not tolerate flooding, so proper irrigation is a critical part of cultivation. Continuously wet or flooded conditions can result in decreased growth, decreased crop yield, nutrient deficiency, and root infection by Phytophthora fungi, and sometimes tree death.

The frequency of irrigation depends on weather, rainfall, variety planted, type of soil, and season of the year. High-volume irrigation with micro-sprinklers is the most common irrigation system in Florida because it serves as under-tree freeze protection. Regular irrigation is vital to fruit production and survival, specifically in California where the climate is semiarid. California groves are irrigated by sprinklers, micro-sprinklers, or drip systems. In Florida, a general rule of thumb is to irrigate one inch of water per week.

Avocado flowers (petals, stigmas, and anthers) are modified shoots and leaves. Flower buds begin to grow during late summer or fall and continue to develop through winter. Blossoming and fruit set occur from late winter through early summer, but most fruits that are harvested develop from flowers that were pollinated in spring. Avocado flowers are about 2/5 inch wide (1 cm) and occur in groups of about 4 to 10 inches. A mature avocado tree can yield thousands of flowers per year. The flower contains both female and male parts. Once matured, the female part opens first and the male parts open the following day. Due to the large number of flowers in a relatively small area, the avocado tree is prone to genetic variability. Domesticated honey bees (Apis mellifera) are the most economically important avocado pollinators; most growers usually keep honey bee hives in their avocado groves to increase pollination and fruit yield. From pollination to maturity, avocados take at least six to seven months to mature. Mature fruits can stay on the tree for months without ripening; avocados do not ripen until after they are picked from the tree.

Right: Hass avocado flower during the functional female stage, the first opening stage. Left: Hass avocado flower during functional male stage, after dehiscence, the second opening stage. Photos by Department of Agriculture and Food, Government of Western Australia

In order for avocado trees to produce fruit, they require sugars, hormones, and mineral nutrients. The type and amount of fertilizer applied depends mainly on the type of soil and age of the tree. In Florida, a 6-6-6 formulation is applied six times a year during the first two years of establishment at a rate of one pound per tree. An 8-3-9 formulation is applied six times a year during the third to sixth years at a rate of two to three pounds per tree. The amount of fertilizer applied increases with the age of the trees. Soils in south Florida are very alkaline (pH above 6.5), which inhibits the absorption of micronutrients. The most common micro-nutrient applied every year in most avocado orchards is iron, which is applied once or twice a year in a chelated form. A multi-nutrient, micro-nutrient blend, such as Keyplex, is also applied as part of the annual fertilization plan.

Harvest

Avocado harvesting stick. Photo by Bethlehem Motors

Since fruit can stay on the tree for long periods of time without ripening, harvesting may easily overlap from year to year. Harvest can begin in the late fall or early winter and may continue until the following fall. Avocados are harvested by hand; pickers work from the ground, use ladders, or remove the fruit using a pole equipped with a pull-cord operated terminal blade and fruit catching bag. In Florida, avocados are harvested from late May through March. A professional picker can pluck about 3,600 avocados a day using the specially equipped pole. When the fruit is picked off the tree, it is not ripe. As soon as it is picked, the ripening process begins.

Post-Harvest Production

In advanced commercial processing plants, once avocados are transported from the field to the factory, they are brought up by conveyer belt where they are graded and sorted. There are three grades of avocado.

  • “U.S. No. 1” consists of avocados of similar varietal characteristics which are mature but not overripe, well-formed, clean, well-colored, well-trimmed and which are free from decay, anthracnose, and freezing injury, and are free from damage caused by bruises, cuts or other skin breaks, pulled stems, russeting or similar discoloration, scars or scab, sunburn, sunscald or sprayburn, cercospora spot, other disease, insects, or other means. Since these fruits are visibly appealing, they are usually shipped to grocery stores and displayed on shelves.
  • “U.S. No. 2” consists of avocados of similar varietal characteristics which are mature but not overripe, fairly well-formed, clean, fairly well-colored, well-trimmed and which are free from decay and freezing injury and are free from serious damage caused by anthracnose, bruises, cuts or other skin breaks, pulled stems, russeting or similar discoloration, scars or scab, sunburn, sunscald or sprayburn, cercospora spot, other disease, insects, or other means. These fruits are not as nice in appearance as U.S. No. 1 fruits, but still taste the same. They are usually shipped to food service establishments and other retail settings for ingredients in food products, such as guacamole.
  • “U.S. No. 3” consists of avocados of similar varietal characteristics which are mature but not overripe, which are not badly misshapen, and which are free from decay and are free from serious damage caused by anthracnose and are free from very serious damage caused by freezing injury, bruises, cuts or other skin breaks, pulled stems, russeting or similar discoloration, scars or scab, sunburn, sunscald or sprayburn, cercospora spot, other disease, insects, dirt or other means. Sometimes the damage does not allow these fruits to ripen correctly, so they are often used as animal feed.

Del Rey Avocado Company quality control employee Lucero Lopez separates blemished fruit along the processing line at the Fallbrook plant. Photo by Don Boomer

During peak production, processing facilities can produce about 500,000 pounds of avocado per day. Once the avocados are sorted, the U.S. No. 1s are shipped off to grocery stores and some restaurants while they slowly ripen on their journey.

Florida avocados ripen best at temperatures of 60° to 75°F (16° to 24°C). At higher temperatures, fruit ripen unevenly and develop off-flavors. The lowest safe storage temperatures before fruit ripen is 55°F (13°C) for West Indian and 40° F (4°C) for most other Florida varieties. Chilling injury is characterized by a browning or darkening of the skin and/or grayish-brown discoloration of the flesh. After fruit ripen, they may be stored in the refrigerator.

U.S. No. 2s will most likely be used to make guacamole, so they are flash-ripened before they are shipped to their final destination. Pressurized, forced-air ripening rooms are specifically designed to ripen avocados at a faster rate. The ambient temperature is increased and about 100 parts per million of ethylene is pumped into the room. Ethylene is a naturally occurring ripening hormone that is artificially used in avocado processing facilities to speed up the process. The avocados in the ripening chamber become ripe in three days as opposed to seven or eight days. When the process is complete, the room is circulated with cold air to shock the fruit and prevent further ripening. After this step, the fruit are checked to ensure that they are at the desired ripeness. They leave the ripening room on a conveyer belt and pass under a machine that shoots a blast of ultrasound waves through each avocado. The machine tells the computer how ripe each avocado is. Avocados that are over or under ripened are shot off the line. At full speed, each sensor can process up to six avocados per second. The avocados that are ready for shipment are packaged by hand and shipped off to their destination.

For more information regarding the movement of avocados in the U.S., please visit the Produce Point of Origin Database.

Cruz Sandoval a buyer with Ingardia Bros. Produce Inc., holds one of only about 30 cases of avocados in the company’s warehouse in Santa Ana on Monday, October 10, 2016. They usually have about 200 cases. Avocado prices had spiked due to a shortage of supplies from Mexico. Photo by Mindy Schauer, Orange County Register/SCNG

Food Safety

Avocados are favorable to the growth of bacteria, as they have a high lipid and moisture content, are low in carbohydrates, and have a non-acidic pH level. Additionally, avocados and avocado products are often consumed raw and without a ‘kill step’ prior to consumption. Fresh cut avocado products carry an additional risk, as piercing the avocado’s skin may allow for the spread and growth of any pathogens potentially present on the exterior. Particularly in restaurant settings, foods like guacamole may present a foodborne risk due to improper storage or food worker handling, the practice of preparing large batches, and inclusion of other raw ingredients previously implicated in foodborne outbreaks, such as cilantro, tomatoes, onions, and hot peppers. From 1984-2008, guacamole was the potential vehicle in 35 outbreaks reported to the Center for Disease Control and Prevention’s Foodborne Disease Outbreak Surveillance System. The most commonly reported pathogens were Salmonella, Shigella, and norovirus, but also included Clostridium perfringens, Escherichia coli, Bacillus cereus, Staphylococcus, Campylobacter, hepatitis A virus, and chemical agents.

Consumers should thoroughly wash avocados under running water before eating, cutting, or cooking, even if the skin will be removed prior to consumption. Promptly consuming fresh avocado after cutting and discarding the avocado skin may further reduce the risk of illness. Consumers should also follow the standard “clean, separate, cook, and chill” food safety practices.

Under the Food Safety Modernization Act (FSMA) and as a part of the FDA’s risk-based and preventative approach to food safety, the agency developed a new, more robust microbiological surveillance sampling approach. This approach aims to collect many samples of targeted foods over a short period of time to determine any common factors among positive microbiological findings. Avocados were selected for sampling in part due to a CDC study’s finding that Salmonella contaminated salsa or guacamole resulted in 26 outbreaks from 1973-2008. This study also found that contaminated salsa or guacamole accounted for nearly 1 in every 25 restaurant-associated outbreaks with an identified vehicle from 1998-2008, accounting for nearly 3.9% of all food establishment outbreaks.

From 2014-2016, the FDA collected and tested both imported and domestic whole fresh avocado samples to determine the prevalence of Salmonella and Listeria. Avocado pulp samples were also collected and tested for Listeria. The prevalence of Salmonella and Listeria on the skins of whole fresh avocados were 0.74% and 17.73%, respectively. The prevalence of Listeria in avocado pulp was 0.24%. From 2017-2019, the FDA collected and tested both imported and domestic processed avocados and guacamole samples to determine the prevalence of Salmonella and Listeria. Final results of this sampling are pending.

Consumption

Avocado consumption in the United States has doubled over the past 10 years and is now about four times higher than consumption in the mid-1990s. Avocados have become more abundant in the U.S. due to a large increase in avocado imports. From 2012-2015, U.S. net production accounted for about 20% of U.S. consumption, compared to about 80% of U.S. consumption in the 1990s.

The Hass Avocado Board (HAB) is an agricultural promotion group established in 2002 to promote the consumption of Hass avocados in the U.S. A 12-member board representing domestic producers and importers of Hass Avocados directs HAB’s promotion, research, and information programs under the supervision of the United States Department of Agriculture (USDA). Funding for HAB comes from Hass avocado producers and importers in the U.S.

For more information on the shelf life of avocados, please visit the FoodKeeper App.

Nutrition

Avocados are considered a superfood. They are nutrient dense, contain relatively few calories, and provide a substantial amount of vitamins, minerals, and other nutrients. One-fifth of a medium-sized avocado (1 ounce) has 50 calories and nearly 20 vitamins, minerals, and phytonutrients, including 4% of the recommended Daily Value (DV) for vitamin E, 4% vitamin C, 6% folate, 8% fiber, 2% iron, 4% potassium, with 81 micrograms of lutein and 19 micrograms of beta-carotene. The 2010 Dietary Guidelines for Americans recommends that Americans increase their intake of dietary fiber and states that dietary fiber that occurs naturally in foods may help reduce the risk of cardiovascular disease, obesity, and type 2 diabetes, as well as help provide a feeling of fullness and promote healthy laxation. One-fifth of a medium California avocado (1 ounce) provides 8% of the Daily Value for fiber, while enjoying one-half of a medium California avocado provides 20% of the Daily Value for fiber. Avocados can act as a “nutrient booster” by enabling the body to absorb more fat-soluble nutrients, such as vitamins A, D, E, and K, in foods that are eaten with the fruit.

      The Best Way to Tell If an Avocado Is Ripe

      When buying avocados, timing is everything. In the span of just a day or two, they can turn from semi-firm to overripe. A soft, super-ripe avocado won’t hold up when diced for a salad, and a firmer one won’t make great guacamole. Unlike other types of fresh produce, you really have to think ahead to when you’ll actually be eating the fruit. (Yes, avocados are a fruit!)

      If you’re making guacamole that day, you need super-soft avocados that will mash up smooth and creamy. Look for avocados with slightly bumpy, dark green skin (black skin is often a sign of over-ripeness). If the small piece of stem can be easily removed from the top of the avocado, that’s another sign that the fruit is ready to eat. Give it a little squeeze. If it yields easily to pressure, you’re good to go.

      If you want to keep an avocado from continuing to ripen, you can store it in the refrigerator for a day or two. Chilling the fruit will change its texture slightly, but it will still be good to eat.

      Let’s say it’s a Thursday, you’re having friends over for brunch Saturday morning, and you want to make a big platter of avocado fritters. Choose smooth skinned, bright green avocadoes that are firm to the touch and allow them to ripen over the next few days. Check on them daily to make sure they are not ripening too quickly.

      The best place to ripen avocados is on your kitchen counter at room temperature. If you want to speed up the process, add a whole, unpeeled piece of fruit to the bag, like an apple or a banana. The bag will trap ethylene gas produced by the fruit, which helps the avocado ripen faster.

      A question for Dan Gill: I have a rather large avocado tree loaded with fruit. When should I pick the avocadoes, and when should I prune the tree? Any information you can give will be appreciated. — Joe Berthelot

      Answer: Harvesting avocado fruit properly can be challenging. The fruit on most fruit trees changes color and softens when it is ripe and ready to harvest (such as citrus, apples, blueberries and peaches). The fruit of avocado trees is best harvested when immature, green and hard and ripened off the tree. Avocado fruit is usually ready to harvest in September, so it’s time to pick some fruit now. Harvest one or two of the largest fruit and allow them to sit on a counter for about a week. If they are ready to harvest, they will ripen properly and will become soft and be ready to eat.

      After that, harvest fruit off the tree hard and ripen them indoors as you need them. If the fruit does not ripen properly — it shrivels, becomes rubbery or begins to rot — then the fruit was not ready to harvest. Harvest a couple more and do the test again.

      When the picked fruit softens and ripens properly, the crop is ready to harvest. You may leave the fruit on the tree and harvest as needed up to a point. As the fruit on the tree begins to get past optimum time to harvest, the tree will begin to drop fruit. Try to get the crop harvested before a lot of fruit begin to drop.

      Pruning an avocado tree may be done, if needed, in spring after the danger of frost has passed. Generally, retain the lower branches as they are easier to harvest. Prune the top of the tree to strong side branches to keep the height under control and maintain a smaller tree.

      Dan Gill is a horticulturist with the LSU AgCenter. Email questions to [email protected] or add them to the comment section below. Follow his stories at www.nola.com/homegarden, on Facebook and @nolahomegardenon Instagram.

      There are a number of simple signs you should look out for when picking the perfect avocado

      Is there anything more satisfying than a perfectly ripe avocado?

      • Catching an avocado in its fleeting window of ripeness is notoriously difficult.
      • Whether an avo will even soften at all depends on whether it was picked from the tree at the right point.
      • There are ways to ensure the avocado you choose will ultimately ripen into a perfect one, though.
      • You can also speed up the ripening process.

      As delicious as they are, avocados are notoriously temperamental fruits.

      It’s no secret that catching your avo in its small window of ripeness is extremely difficult — and there’s nothing worse than find one that’s too hard, or mushy and brown.

      Then there are the avocados which seem never to soften at all, and you reluctantly end up eating the hard yet watery green flesh atop your toast.

      Many people believe they have ways to hack the system — popping your avocado in the fridge to stop it ripening too soon, or placing in the oven on a low heat to speed up the softening process, for example — but how much can we really do? Does finding a perfect avocado really come down to pure luck?

      As it turns out, there are certain things to look out for in the supermarket to ensure the avocado you take home will ripen perfectly.

      First, however, it’s useful to know the science behind how avocados ripen.

      How avocados ripen

      Avocados don’t actually ripen while on the tree — it’s not until they’re picked that the flesh will start to soften. However, it’s important that the millennial staple is picked at just the right moment.

      “The fruit does not ripen while attached to the tree, even when physiologically mature, because of an inhibitor in the fruit stem,” Kantha Shelke, a food and nutrition scientist and member of the Institute of Food Technologists, explained to HuffPost.

      “It appears to be nature’s way of protecting the fruit from damage from high temperatures. Even exposing the fruits on the tree to ethylene gas will not ripen it.”

      Read more: There’s a restaurant in Brooklyn that serves all avocados — we tried it

      It’s only once an avocado has been picked that it will start to soften, but it needs to stay on the tree long enough to ensure it has the right balance of oil and dry matter, which means it’s imperative that the fleshy fruit isn’t taken from the tree too early.

      If an avocado is picked too soon, it will never soften, will remain hard and watery, and your brunch will be ruined.

      How to pick a perfect avocado

      There are a number of tricks you can use to ensure you choose a winning avocado, according to HuffPost:

  1. Give the fruit a gentle shake — if the seed rattles, the avocado should ripen quickly.
  2. Avoid avocados with loose skin.
  3. Steer clear of fruits that appear to be going bad at the stem end.
  4. Look for a classic pear shape.
  5. Avoid fruits that are softer in patches, as these are likely bruises.
  6. Don’t worry about blemishes or marks on the skin, though.
  7. Give it a gentle squeeze — if it slightly yields to pressure, it’s like to be ripe. If it’s very firm, it’s not ready, and if it feels very soft, it’s overripe.

Once you’ve selected your avocado and taken it home you’ll know it’s ready to eat when you remove the stem cap and underneath is green (if it’s brown, it’s overripe. Sorry).

How to speed up the ripening process

If you bought your avocado on Wednesday but by Friday it’s still on the firm side, fear not: there is a way you can ripen up your avo for the weekend, according to HuffPost.

All you need to do is place the avocado in a brown paper bag or sealed container alongside other fruits which produce ethylene, such as apples and bananas.

Don’t bother heating the avocado in the hope of it ripening, though. It apparently won’t work.

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