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Unformatted text preview: F r e s h - C u t P r o d u c t s :M a i n t a i n i n g Q u a l i t y a n d S a f e t y Section 3c STANDARDTZNIONOF QTJALITY
By Adel A. Kader and Beth Mitcham Quality of fresh-cut fruits and vegetables is a
combination of attributes that determine their value
as human food. These quality factors include visual
appearance (freshness, color, defects, and decay),
texture (crispness, turgidity, juiciness, firmness,
toughness, and tissue integrity), flavor (taste and
smell), nutritive value (vitamins A and C, minerals,
and dietary fiber), and safety (absence of chemical
residues and microbial contamination).
Quality of the fresh cut products depends
upon quality of the intact commodity and its maintenance until preparation, method of preparation, and
subsequent handling conditions (speed of cooling, 2. Pre-harvest factors: Climatic conditions such as
temperature and rainfall influence quality at harvest
and length of postharvest-life since the effects of
environmental stresses are cumulative. Cultural
practices such as soil type, nutrient and water
supply, pest management, and crop load affect the
composition of the harvested plant part. Excess
water supply, excess nitrogen, and low calcium are
related to poor postharvest-life of fresh fruits and
vegetables. Contact of the edible plant part with soil
where un-sterilized organic fertilizers are used
increases the potential for contamination with
human pathogens. maintaining optimum temperature and relative
humidity, expedited marketing, and proper sanitation). Fresh-cut operations should not be viewed as a
way to utilize inferior quality, overmature, or defec- 3. Harvesting stage: Selecting the optimum
maturity for each commodity is essential to providing the best combination of eating quality and
postharvest-life. Vegetables picked at a point when tive commodities that can not be marketed intact.
Only good quality intact fruits and vegetables and
cultivars that are more suitable for preparation of
cut products should be used in order to assure good
quality for the consumer. they are still growing (such as broccoli, sweet corn,
summer squash, and asparagus) have very high
metabolic activity and small amounts of storage
reserves, while those harvested mature (such as
winter squash and potato) have low metabolic Factors Influencing Composition
of Intact Commodities and Quality 1. Genetic factors: For many fruits and vegetables
there are large differences among cultivars in
composition and quality. For example, vitamin A
content of carrots ranges from 8,500 to 19,500 IU per
100 grams and flesh browning potential varies
greatly among apple and pear cultivars. Use of
broccoli and cauliflower cultivars that form less
compact heads may facilitate cutting the florets with
less damage. It is possible that new cultivars with
desired characteristics will be developed through
plant breeding and biotechnology; examples include
lower polyphenol oxidase activity (less browning of
cut products), reduced activities of cell waII degrading enzymes (better firmness retention and less
exudation of cell sap from cut products), and/or
better flavor (higher sugars, lower acidity, more
intense aroma, no off-flavors). activity and large amounts of storage reserves.
Immature vegetables deteriorate much faster than
mature vegetables. Stringiness and ribbiness of over
mature cabbage, celery, and lettuce render them
unsuitable for fresh-cut products. Fruits taste best
when picked fully-ripe or nearly so, but these fruits
may be too soft for a fresh-cut product. Compromises
between optimum flavor and texture are often
Maintaining between harvest and preparation:
the quality of fresh fruits and veg- etables between harvest and preparation (peeling,
cutting, etc.) depends upon care in handling (minimizing mechanical injuries), rapid cooling, maintenance of optimum temperature and relative humidity, and exclusion of ethylene from ethylene sensitive
commodities. Fruits picked mature-green or
partially-ripe should be ripened before cutting to
ensure good eating quality. Fresh-Cut Products: Maintaining Quality and Safety Preparation Procedures Influence Quality of Signs of Deterioration Section 3c of Fresh-cut Products Cut Products
1. Cleaning: Thorough cleaning of the intact commodity (including use of chlorine to reduce microbial
load) is essential to producing a clean cut product.
The microflora of fresh cut fruits and vegetables may
originate from pre-harvest contamination or from
processing equipment. Thus, both the commodity
and equipment used must be kept as clean as possible during preparation. Washing of the cut product
removes tissue exudate, which can be a favorable
substrate for microbial growth.
2. Cutting: Preparation of fresh-cut products involve
wounding of the plant tissues which leads to increased rates of respiration, ethylene production,
browning, water loss, and overall quality deterioration. The greater the wounding (such as cutting into
smaller pieces), the shorter the post-preparation life
of the product. For example, the post-cutting life of
peeled and cut carrots is longer than that of sliced
carrots, which is longer than that of grated carrots.
Sharp knives (blades) will reduce product injury.
Presence of off-size (large pieces for
the product) and/or inedible tissues (core pieces,
roots, peels, etc.) detract from the quality of the cut
4. Packing: Proper packaging can help maintain
quality of the cut products by reducing water loss
and tissue browning. If packaging restricts gas
diffusion too much, it is possible that oxygen depletion and/or accumulation of carbon dioxide can lead
to fermentative metabolism and off-odor development.
Cooling and maintenance of optimum temperature
[0"C (32"F) for most products] and relative humidity
(95 to 98%) during transport, in temporary storage at
destination wholesale and retail handling facilities,
and during retail display are the most important
factors in maintaining quality of cut products.
Expedited handling (reducing the time between
preparation and consumption) ensures good quality.
Dating of fresh cut product packages (such as preparation date, sell by date, or best if used by date) is
highly desirable. 1. Bruised or broken pieces resulting from packaging too tightly and/or rough handling.
2. Wilting, wrinkling, shrivelling, flabbiness, flacidity, and excessive drying due to water loss.
3. Mushiness resulting from excessive tissue softening.
4. Development of off-colors (yellow, red, tan, brown,
or black discoloration) due to loss of chlorophyll
(green color), enzymatic browning, and/or physiological disorders such as tip burn of lettuce.
5. Presence of free liquid within packages of freshcut products. This may be associated with sliminess and incidence of decay-causing pathogens
(such as soft rot bacteria).
6. Presence of undesirable odors. such as fermented
aroma due to accumulation of ethanol, acetaldehyde, and/or ethyl acetate; foul odor due to
bacteria; or musty and molding smell due to
7. Bloated bags due to excess gas in sealed bags
resulting from fermenting or decaying product.
Wounding plant tissues can accelerate loss of vitamins, especially the water-soluble vitamin C. All the
recommended procedures for maintaining overall
quality of cut fruits and vegetables should help
quality. Our data so far
indicates that vitamins A and C losses in cut fruits
become significant only after the products visual
quality has deteriorated below the level of marketability. However more research is needed to quantify
minimize loss of nutritional changes in nutrients due to cutting and identify
procedures for reducing losses in nutritional quality
during the time between preparation and consumption.
grade standards for fresh cut
There are no U.S.
products. However, the Fresh Products Branch of the
USDA Agricultural Marketing Service, Fruit &
Vegetable Division and the Fresh-cut Produce F r e s h - C u t P r o d u c t s :M a i n t a i n i n g Q u a l i t y a n d S a f e t y Industry developed
inspection instructions that were
published in November 1993then reprinted with a
few revisionsin May 1994.These instructions
provide guidelinesand definitions that can serve as a
commonlanguagefor the Inspection Servicein the
inspectionand certification of fresh-cut (ready-touse) products. [Copiesof this booklet (Fresh-cut
produce:shipping point and market inspection
instructions)can be purchased($tO per copy)from
the USDA-AMS-Fruit & VegetablesDivision or from
the International Fresh Cut ProduceAssociation]
Brecht,J.K., 1995.Physiologyof lightly processed
fruits and vegetables.
HortScience30:L8-22. Section 3c Romig, W.R. 1995. Selection of cultivars for lightly
processedfruits and vegetables. HortScience 30:3840
Shewfelt, R.L. 1987. Quality of minimally processed
frui ts and vegetabl es.J. Food Qual i ty 10 : 143- 156
W atada, A .8., N .P . K o, and D .A . Mi nott. 1996.
Factors affecting quality of fresh-cut horticultural
products. P ostharv. B i ol . Technol . 9:115- 125
Wiley, R.C. (editor). t994 Minimally processed
regfrigerated fruits and vegetables. Chapman Hall,
New York, 368 p. ...
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This note was uploaded on 05/03/2009 for the course FST 160 taught by Professor Giovanni during the Winter '08 term at UC Davis.
- Winter '08