Post-Harvest Celery Cooling

Celery is almost synonymous with crisp, fresh food. It is often added to dishes to provide a crunchy texture or it may be used as a fresh, edible garnish for drinks, dips, and other tasty treats. However, while celery is naturally fresh and firm in order to keep it that way proper harvesting, handling, cooling, and storage methods must be carefully observed. Let’s take a closer look at celery and the factors that affect its quality.

General Facts About Celery

The celery species is Apium graveolens var. dulce and it is a member of the apiaceae plant family. Celery is most often associated with its leaf stalks, called petioles, and these stalks have been selectively bred to be long, wide, and solid. However, in addition to the stalks, celery leaves may also be consumed in salads or soups, or dried into herbs. Celery seeds also make a popular seasoning. They are often ground up and combined with salt to form “celery salt;” although, they may also be used for their oil, which is a common and useful ingredient in various pharmaceuticals and perfumes.

Celery forms the foundation of many culinary and cuisine styles including cajun and creole cooking as well as French mirepoix. Celery is also common in a wide range of soups including traditional chicken soup recipes.

Nutritional Facts About Celery

Celery is often falsely purported to be a negative calorie food – that is a food that takes more calories to digest than are yielded from digestion, thus resulting in a net calorie loss. However, this is false. Scientific study indicates that a typical stalk of celery provides about 6 calories and only takes about .5 calories to digest, thus yielding a net calorie gain, not loss, of about 5 and a half calories. However, while celery is not calorie negative, it is nevertheless a useful and common component of many low-calorie diets because it provides low calorie mass that often helps satisfy hunger with few additional calories.

Celery Allergies

Many people are highly allergic to celery and can suffer deadly anaphylactic shock if they consume even trace amounts. The allergy is so severe that the reaction may occur even from food that was merely processed on equipment that was also used with celery. The allergy is more common in Europe than in North America. In fact the European Union requires that all foods that may contain celery or have come into contact with equipment that touched celery be labeled with a warning in much the same way that peanut warnings are required in the US.

General Information About Cooling and Storing Celery

Celery has a long shelf life and maintains its quality quite well when it is properly handled, cooled, and stored. The following are key factors:

Harvest – Celery should be harvested using sharp blades to prevent damage to the stalk. It should also be quickly pre-cooled to remove field temperatures and sanitized to remove bacteria, fungi, and pathogens which may hasten decay.

Temperature – Celery should be stored at a temperature of about 32°F to 36°F and is not prone to chill damage unless temperatures drop below 31.1°F.

Relative Humidity – Celery has a very high water content and thus also needs a very high relative humidity to avoid shriveling and weight loss, which also compromises texture and firmness. A relative humidity of about 98%-100% or full saturation is desired for maximum crispness.

Storage – Celery is usually stored in stalk bunches with all or most of the leaves removed. It may also be sorted and graded based on its quality, color, size, and other factors.

Shelf Life – Under ideal conditions fresh, non-frozen celery may last up to 1-3 months.

Methods of Cooling Celery

The following cooling methods are common and effective for proper celery cooling:

Hydrocooling – Celery is often pre-cooled using the hydrocooling method, which involves removing field heat by rapidly submerging the celery in near-freezing water.

Hydrovac Cooling – Hydrovac cooling involves vacuum cooling – increasing the pressure until water evaporates – while also adding additional chilled water to prevent dehydration and moisture loss.

Forced-air Cooling – Forced-air cooling involves pulling cold air through the celery, thereby forcing circulation and ensuring more rapid cooling than would be possible with room cooling alone.

Proper cooling and storage of celery is key for ensuring maximum taste, quality, and freshness. SEMCO/SEMCOLD LLC designs and installs high quality, dependable produce cooling and storage systems that are ideal for use with celery and other vegetables. Our systems are fully customizable to ensure that every clients gets the exact right system for their particular needs. Please contact us for additional information.