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Issue No. 609

The Vegetarian Newsletter 

A Horticultural Sciences Department Extension Publication on 
Vegetable and Fruit Crops 

Eat your Veggies and Fruits!!!!!

Publish Date: 
February 2016

Tomato and Watermelon Variety Evaluation Program

Josh Freeman, North Florida Research and Education Center, Quincy, FL

In today’s competitive vegetable production environment it is critical that growers can produce the largest amount of high quality produce on every acre they farm in order to maximize efficiency. Seed suppliers often introduce new varieties every year and it can be difficult for producers to keep up with what could be the best varieties for their operation. In many cases, newer improved varieties can increase yield by 25% which could make a significant impact on farm economics. Our program of variety evaluation seeks to give producers a first look at new varieties as compared to industry standards. We conduct tomato variety trials during the fall and spring and watermelon trials during the spring. We seek to create a production scenario that mimics commercial production as much as possible. These trials can never include all possible varieties but we try to engage stakeholders and include as many relevant varieties as possible. As you can see in the tables below (results from two recent variety trials) there are several newer watermelon and tomato varieties that offer significant improvement in yield over some standard varieties. Yield is not the only factor to consider when choosing a variety for your operation. Other important factors such as disease resistance, fruit quality, and earliness. Consult your local county extension agent and the Vegetable Production Handbook of Florida (http://edis.ifas.ufl.edu/pdffiles/cv/cv29200.pdf) before making any substantial decisions about your operation.

We make an attempt to conduct these variety trials every year so stay in touch for the latest variety trial results (http://nfrec.ifas.ufl.edu/faculty/dr-josh-freeman/#d.en.193420).

Figure1. Tomato Variety Trial in Quincy, FL

1_1.jpg

2015 Watermelon Variety Trial

Twin row plots containing five triploid watermelon seedlings per row were established on March 16, 2015 at the North Florida Research and Education Center (NFREC) in Quincy, FL. The experimental design used was a randomized complete block with four replications. Soil type at NFREC is Orangeburg loamy sand with pH 6.3. Watermelon seedlings were transplanted into raised beds fumigated with a mixture of chloropicrin and Telone and covered with black polyethylene totally impermeable film mulch. Beds were 30 inches wide and 8 inches tall.  Row spacing was 8 feet and plants were spaced 3 feet in the row. Standard crop protection practices were used to maintain vine health. The diploid pollinizer variety SP-6 was used. Four pollinizer plants were included in each plot, two per row. Harvests were performed on June 8 (84 days after planting), June 18 (94 days after planting), and July 1 (107 days after planting). Each fruit was weighed individually. Five fruit per plot were cut for quality analysis following the June 8 harvest. Experimental data was analyzed using the GLM procedure in SAS and means separation was performed with Duncan’s multiple range test at the 5% level, when appropriate. 

Watermelon Variety Trial – Spring 2015 Cumulative Harvest – NFREC Quincy

Variety

Source

Yield (lb/acre)z

Avg Weight

(lb)

% Total Yield by Count

Hollow Heart y

Hard Seed x

°Brix

30

36

45

60

Maxima

Origene

118124 a

18.5

ab

23

26

37

14

0.4

bcd

0.5 ns

12.0

a

Talca

Origene

115881 ab

17.8

a-e

13

30

39

19

0.2

bcd

0.6

11.2

a-e

Wolverine

High Mark

111706 abc

16.5

b-f

6

26

43

25

0.7

a-d

0.3

11.5

a-d

SV 7112

Seminis

108524 abc

17.9

a-d

17

31

38

14

0.4

bcd

0.1

11.2

a-e

Premont

Clifton

107272 abc

18.1

a-d

11

33

41

15

0.2

bcd

0.5

11.3

a-e

SV 7018

Seminis

104824 a-d

17.4

a-f

6

29

46

19

0.1

cd

0.4

11.4

a-d

Razorback

High Mark

104305 a-d

17.0

b-f

9

28

41

22

0.2

bcd

0.3

11.1

a-e

Grafted Fascination

Tri-Hishtil

103951 a-d

18.3

abc

19

29

39

13

1.1

abc

1.5

11.1

a-e

Sugar Fresh

Syngenta

103844 a-d

18.0

a-d

13

21

45

21

0.3

bcd

0.1

10.4

e

AC 7197

Nunhems

101657 a-d

16.4

b-f

8

25

43

24

0.1

cd

0.6

11.2

a-e

AC 7187

Nunhems

100751 a-d

17.3

a-f

4

32

46

18

1.6

a

0.4

11.6

a-d

Crunchy Red

Harris Moran

99538 a-d

17.2

a-f

14

28

38

21

0.2

bcd

0.2

10.6

de

7015

High Mark

99291 a-d

16.7

b-f

11

24

35

30

0.3

bcd

1.6

12.0

a

Traveler

Harris Moran

97140 a-e

16.3

c-f

4

19

44

34

0.1

cd

0.2

11.5

a-d

Fascination

Syngenta

95964 a-e

17.1

a-f

13

21

39

27

0.3

bcd

1.3

10.8

de

Joy Ride

Seminis

95852 a-e

17.6

a-f

13

33

36

18

0.0

d

0.2

12.0

a

Exclamation

Syngenta

95343 a-e

16.7

b-f

9

19

51

21

0.2

bcd

0.3

11.2

a-e

Summer Breeze

Seminis

94098 a-e

16.4

b-f

5

26

40

29

0.3

bcd

0.2

11.8

abc

Lucille

Origene

93732 b-e

16.4

b-f

7

17

52

24

0.2

bcd

0.1

10.9

cde

Warrior

Nunhems

92535 b-e

19.2

a

19

34

35

12

1.6

a

0.3

11.1

a-e

SV 0241

Seminis

92123 b-e

16.0

ef

4

16

39

40

0.7

a-d

0.5

11.3

a-e

AC 6177

Nunhems

92027 b-e

15.7

ef

2

21

41

36

0.2

bcd

0.7

11.1

a-e

Captivation

Syngenta

90213 cde

15.5

f

3

12

43

42

0.0

d

0.3

10.9

cde

Sweet Polly

Siegers

89897 cde

16.1

def

3

19

41

38

0.0

d

0.1

10.7

de

AC 7167

Nunhems

89771 cde

16.7

b-f

4

21

45

30

1.2

ab

0.5

11.0

b-e

TRI-X 313

Syngenta

87660 cde

16.0

def

7

20

44

29

1.5

a

0.1

11.9

ab

Embasy

Nunhems

82555 ed

16.1

def

6

18

45

30

0.4

bcd

0.4

10.8

ed

Troubadour

Harris Moran

81676 ed

16.0

def

4

14

43

39

0.1

cd

0.5

11.6

a-d

Sweet Dawn

Syngenta

74314 e

17.7

a-e

9

34

46

12

0.0

d

1.0

10.8

de

Means are to be compared within columns, means not followed by the same letter are significantly different at P≤0.05, ns = not significant

Z Yields are based on a plant population of 1815 plants per acre

Y Hollow heart is a visual rating of severity on a 0-5 scale with 3-5 being unmarketable

X Hard seed were counted on four faces of cut fruit – Data represents average hard seed count per fruit

Fruit count is based on the following weights –

    60 count = ≥ 9 and ≤ 13.5

    45 count = > 13.5 and ≤ 17.5

    36 count = > 17.5 and ≤ 21.5

    30 count = > 21.5

2015 Fall Tomato Variety Trial

Single row plots containing 12 tomato plants were established on August 3, 2015 at the North Florida Research and Education Center (NFREC) in Quincy, FL. Soil type at NFREC is Norfolk loamy fine sand with pH 6.5. Experimental plots were arranged in a randomized complete block design with four replications. Tomato seedlings were transplanted into raised beds covered with white on black polyethylene mulch.  No fumigant was applied because of time constraints. A bed top application of Reflex and Dual Magnum herbicides were applied after bed formation and before plastic was deployed. Beds were 30 inches wide and 8 inches tall. Row spacing was 6 feet and plants were spaced 20 inches in the row.  An assessment of bacterial spot severity was conducted on October 16 prior to the first harvest. Harvests were performed on October 19, October 29, and November 12 at the mature green to early breaker stage. Fruit were weighed and graded according to USDA standards. Experimental data was analyzed using the GLM procedure in SAS and means separation was performed with Duncan’s multiple range test at the 5% level, when appropriate.

Tomato Variety Trial – Fall 2015 – NFREC QuincyCumulative Harvest

Variety

Source

% Marketable

Avg Weight (grams)

Marketable Yield (lb/acre)

% Bacterial Spot Severity

Med

Large

XL

Total

Red Morning

Harris Moran

91

a

200

ns

8949

a-d

23487

ab

36006

ns

68279

a

53

a-e

Quincy

Seminis

85

cd

190

6695

b-e

21600

abc

28672

56967

ab

44

cde

SV 7631

Seminis

91

ab

205

4710

ef

16025

cd

36086

56821

ab

50

a-e

FL 91

Seminis

90

ab

197

7532

a-e

17925

bcd

30811

56628

ab

41

de

XTM 7262

Sakata

88

a-d

200

9926

abc

19407

a-d

27254

56586

ab

42

de

XTM 2261

Sakata

85

cde

213

6133

cde

21677

abc

25324

56095

ab

65

a

Resolute

Bejo

90

ab

194

4641

ef

14814

d

34287

53742

ab

42

cde

FL 47

Seminis

89

abc

206

7844

a-e

19062

a-d

26144

53050

ab

48

b-e

BHN 602

BHN

88

a-d

200

6443

b-e

19114

a-d

27238

52795

ab

45

cde

Volante

Sakata

89

ab

202

6133

cde

18531

bcd

27081

51745

ab

51

a-e

SV 1131

Seminis

85

de

186

9094

def

19268

a-d

25316

49627

b

50

a-e

Red Bounty

Harris Moran

89

ab

191

7073

a-e

16572

cd

23930

47575

b

57

abc

XTM 2260

Sakata

86

cd

182

9920

a-e

18624

bcd

16794

45338

b

62

ab

HMX 3837

Harris Moran

87

a-d

219

10924

ef

19824

a-d

14044

44792

b

56

a-d

Dixie Red

Seminis

87

bcd

198

2391

f

9458

e

32827

44675

b

52

a-e

Means are to be compared within columns, means not followed by the same letter are significantly different at P≤0.05, ns = not significant


FAWN Tools for Localized Freeze Forecasts

Gary K. England

Multi-County Extension Agent – Fruit Crops

An act of the Florida Legislature in 1997 established the Florida Automated Weather Network (FAWN) as a statewide system that consisted of five UF/IFAS Extension Weather Stations and added 11 new stations for a total of 16 by 1998.  The FAWN network now consists of 44 stations that monitor temperature at four locations (10 cm deep in the soil, 60 cm above the soil, and two and ten meters above the soil), barometric pressure, solar radiation, and wind speed and direction. In addition the system calculates dewpoint and wet bulb temperature as well as evapotranspiration (ET).  All data are automatically collected and transmitted to the FAWN Offices in Gainesville where they are archived and posted on the FAWN Website (http://fawn.ifas.ufl.edu).

Over the years, a number of tools designed to provide important information to growers were added to FAWN.  Some of the most popular resources are Irrigation Scheduling and Citrus Pesticide Tools, along with the Cold Protection Toolkit.

The Cold Protection Toolkit was designed as a resource to growers who produce crops that are sensitive to extreme winter temperatures and require some type of cold protection strategy.  Application of water, typically through an irrigation system, is one of the most popular means of protecting sensitive crops from cold. The goal of the Cold Protection Toolkit is provide the producer with information to achieve cold protection in the most water efficient means, thus ultimately reducing the amount of water necessary to protect crops.  Summarized below are some of the more popular components of the Cold Protection Toolkit.

I.  National Weather Service (NWS) Forecast - Interactive Map

The interactive map can give an NWS Pinpoint Forecast for any location (Figure 1.).  On the map, locations of FAWN weather stations, historical locations of NWS Fruit Frost Weather Stations and My Florida Farm Weather Stations (FDACS Stations) are noted.  NWS Pinpoint Forecasts are generated by correlating weather data from the nearest official NWS reporting stations around the state with historical weather data form the now defunct network of several hundred NWS Fruit Frost Stations typically located in significant agricultural production regions around the state.  As a freeze approaches, NWS meteorologists will generate a forecast for the official NWS reporting stations in their region. Pinpoint Forecasts are generated using correlations to historical data from the nearest Fruit Frost Station for a given location.

II.  Forecast Tracker for FAWN Stations

Once a grower has obtained an NWS Pinpoint Forecast for their location, they can observe how actual temperature measurements at FAWN stations are trending compared to a graph of the NWS forecast for the station.  Growers typically know the critical temperature where their crop could be damaged by excessively cold temperatures.  If the temperature data generated by Forecast Tracker is trending significantly lower or higher than the NWS Forecast, growers can take critical temperature into consideration and decide whether their plan of action for a cold event should be altered.

III. Minimum Overnight Temperature

This tool utilizes measurements of ambient temperature and dewpoint calculations taken at sunset at each FAWN station, and are utilized as variables in a calculation called the Brunt Equation.  The result of the calculation is the approximate low temperature that can be expected at that station.

The Brunt Equation has proven to be most effective during radiation freeze events that occur when winds are minimal or calm and significant heat escapes from the landscape to a cloud free sky.  During advective freezes, or those typically accompanied by significant winds, colder and drier air is still actively moving into the region.  Since dewpoints tend to drop as additional colder dryer air enters the region during advective freezes, the Brunt Equation may not be as effective.

IV.  Wet-Bulb Based Irrigation Cutoff Temperature

The Wet-Bulb Based Irrigation Cutoff Temperature is a tool designed as a guide for growers to determine when to turn off their irrigation system with minimal risk of the temperature of their plant material falling below the critical temperature established for their crop.  The wet bulb temperature is the temperature resulting from evaporative cooling that occurs when water is introduced into the system and subsequently evaporates.  As a rule of thumb, wet bulb temperature is approximately in between ambient and dewpoint temperatures.

If irrigation water applied to a crop is either turned off or interrupted by equipment failure when the wet bulb temperature is lower than the critical temperature of the crop, significant crop damage could occur as evaporative cooling results in the temperature of plant tissue “crashing” to the wet bulb temperature.  When wet bulb temperature in the field is above the critical temperature of the crop, the system can be turned off with minimal risk of damage.  This concept can also be run in reverse to determine a safe time to turn on the irrigation system as temperatures drop during a potentially damaging cold weather event.

There are many other tools and informational content of use to growers and others on FAWN.  Several UF/IFAS Extension Agents that work with producers of cold sensitive crops conduct Winter Weather Schools in the fall of most years.  Workshop content typically consists of principles of cold protection, understanding freeze forecasts and updates of new resources available on FAWN.

2_1.png

Figure 1. Screen shot of the NWS Forecast interactive Map on FAWN.  Users can click anywhere on the map to obtain the NWS Pinpoint Forecast for the location. 


Agenda

Innovative Genetics and Breeding Approaches to Address Critical Issues for Florida Horticultural & Agronomic Crops

June 14, 2016

1:30 – 5:30 PM

Keynote Lunch Speaker: Dr. Dave Clark, Environmental Horticulture Department.
UF/IFAS Plant Breeding: Basics for understanding what we do, why we do it, and how we do it

1:30 - 1:45Welcome and Pretest
1:45 - 2:15

Marker-Assisted Selection in Breeding

James Olmstead, UF Horticultural Sciences Department, Gainesville, FL

2:15 - 2:45

Genetic Approaches for Improvement in UF/IFAS Sweet Sorghum Breeding Program

Sanyukta Shukla, Postdoctoral Research Associate, Microbiology and Cell Science Department, Gainesville, FL
2:45 - 3:15

Propagating Native Species to Protect Wild Ecosystems

Mack Thetford, Environmental Horticulture Department, WFREC, Milton, FL
3:15 - 3:30Break
3:30 - 4:00

Controlling Establishment of Non-native Species

Zhanao Deng, Environmental Horticulture Department, GCREC, Balm, FL

4:00 - 4:30

Developing Non-conventional Crops for Florida

Jose Chaparro, Horticultural Sciences Department, Gainesville, FL

4:30 - 5:00

Application of Genetic and Breeding Techniques for Disease Resistance

Jude Grosser, Horticultural Sciences Department, CREC, Lake Alfred, FL
5:00 - 5:15Post-test and conclusion

Article 18 - Protecting workers from heat illness

Temperatures were above 91 degrees with a heat index of over 102 on June 14, 2015. The autopsy findings indicated heat exhaustion as the cause of death. Armin Velazquez Ramos, 37, was subcontracted to pick oranges at a citrus grove.  According to the police report, after the lunch break, Velazquez became disoriented, complained of wanting water and started exhibiting signs of heat exhaustion. About 45 minutes after he left his tree to get water, the crew leader found Ramos lying along a dirt road near the water point. The crew leader stated that he can tell the workers to take breaks and provide water, but he can’t provide shade for them. The citation stated that the contracted crew leader did not implement a heat illness prevention program for his employees and failed to provide an environment free from recognized hazards likely to cause death.

Agriculture ranks as one of the most dangerous occupations in the U.S.  Between 2003 and 2011, more than 5,000 farm laborers died of various illnesses and accidents while at work. For some, the death of Armin Velazquez Ramos came as a shock, but for others it did not, as it has been shown that the risk of heat illness from high temperatures is one of the most serious challenges to the safety and health of farmworkers.

This is why, at UF/IFAS, we developed a new heat illness class that will be offered as part of the Farm Labor Supervisor Training Program. This class covers personal risk factors, prevention and how to recognize and treat various levels of heat illnesses. Detailed examples of agricultural workers who died from heat-related illnesses are used to emphasize the importance of symptom awareness.

In order to avoid fatalities, it is important that we pay special attention to new and returning migrant farmworkers.  Most people who die from heat stroke at work are in their first few days on the job. It takes time for the body to adapt to working in a new temperature and conditions, even if people have done similar work in the past. Just one week off from working in heat can put workers at higher risk upon their return to hot and humid weather.

There are three levels of heat illness.  It starts with heat cramps, then the intensity increases to heat exhaustion and finally, the most lethal: heat stroke.  Heat cramps start with leg, arm, and/or stomach cramps, dizziness, and headache. If left untreated, the next level, known as heat exhaustion, includes heavy sweating; fast, weak pulse; and nausea or vomiting. The symptoms of heat stroke include possible unconsciousness, fainting, convulsions, and high body temperature.

Heat illnesses and deaths are preventable. In the class, we talk about preventative measures that can be employed to ensure that individuals minimize their risk of developing heat illness.  Water should be available nearby and workers should drink some every 15 minutes, even if not thirsty. Rest should be available in the shade or air conditioning to cool the body down. Appropriate clothing helps, such as a hat and/or light colored clothing.

It is the employers’ responsibility to provide workplaces that are safe from excessive heat.  To save lives, it is important to know the signs and symptoms of heat-related illnesses, watch for changes in behavior of workers, and have an emergency plan. .

We teach other topics in addition to safety as part of the Farm Labor Supervisor Training program.  For example, Wage & Hour classes teach rules and regulations that keep farm workers treated fairly and paid correctly.   We also have a class on Discrimination and Harassment, with a particular focus on sexual harassment, to keep people in the fields and groves protected.   

Farm Labor Supervisors and other attendees may take one or as many classes as they choose. If people complete eight classes and pass a test in each, they can earn the Certificate of Farm Labor Management.  Three classes are specifically required to earn the Certificate:  Wage & Hour; Human Resource Compliance, and one class in worker safety.   All classes are offered in both English and Spanish.   Public trainings are held in the fall in multiple locations around Florida, and private trainings can be arranged at any time.  For more information go to:  http://swfrec.ifas.ufl.edu/programs/economics/fls/

Authors:   Zayala, S., and C. Thissen.  Sharon Zayala is a Humility of Mary volunteer who is working with the Farm Labor Supervisor training program at the University of Florida’s Southwest Research and Education Center, Immokalee, FL, 239-658-3400. Carlene Thissen is the Coordinator of the program, reporting to Fritz Roka.  239-658-3449 carlene@ufl.edu.


Strawberry fruit held in different types of clamshell containers:

a comparison of cooling and shipping characteristics

Steven A. Sargent, Jeffrey K. Brecht and Donald J. Huber

Horticultural Sciences Department, University of Florida,

PO Box 110690, Gainesville FL 32611

Strawberries are one of the most perishable of our fresh-market crops. Our previous tests showed that timely cooling after harvest is critical to extend fruit quality during shipping and handling operations. Strawberries that were cooled within 1 hour of harvest had significantly higher quality after 7 days storage at 34°F compared with those that had a 6-hour delay to cooling. Fruit from the delayed cooling treatment had 20% more soft fruit, 50% higher weight loss, and lower levels of sugar and other nutrients including Vitamin C (Nunes et al., 2005).

With a Specialty Crops Block Grant from the Florida Dept. of Agriculture and Consumer Services, we also previously conducted extensive testing of commercial forced-air cooling systems for strawberries and found that the time for 7/8 Cooling, to about 38 to 42°F pulp temperature, varied significantly (Sargent et al., 2014). These differences in cooling times are caused by several factors that influence the uniformity of pulp temperatures during forced-air cooling:

•        the number and arrangement of vent openings of the clamshell and flat (carton)

•        clamshell position on the pallet layer (clamshells on the air inlet side cool faster than those on the air outlet side).

•        pallet position within the cooling tunnel (those pallets furthest from the fan tend to cool slower)

•        whether or not openings under pallets are blocked during cooling

This current study was funded by the Florida Strawberry Growers Assn. and had the goal to evaluate rigid clamshell containers currently used by Florida growers for cooling efficiency and the extent of compression bruising during storage. The complete report is available upon request from the FSGA (Sargent et al., 2016).

In spring 2015, samples of five, 1-pound and three, 2-pound container types were obtained from Florida shippers who represented the majority of fruit volume in the state (Table 1). There were two sets of tests. Cooling tests were conducted on 1-lb and 2-lb clamshell types using two, small-scale, forced-air coolers. Subsequent cooling tests were conducted only for 1-lb clamshell types with a commercial forced-air cooler.

For each test, strawberries were commercially harvested into the various clamshell types at Fancy Farms, Plant City. For the small-scale tests, there were four flats for each clamshell type (eight, 1-lb clamshells per flat and four, 2-lb clamshells per flat). Following harvest, the flats were taken immediately to the coolers at Wish Farms, Plant City, where each small-scale unit cooled four flats at a time. For these tests, inlet and outlet pulp temperatures were measured for each flat during the recommended 7/8 Cooling Time (Figure 1). Air temperature in the cold room was about 34oF.

Subsequently, 1-lb clamshells were cooled in a commercial forced-air cooler at Wish Farms. For this test, two flats with the same clamshell type were placed end-to-end, outside-to-inside, within a pallet in the forced-air cooling tunnel and inlet and outlet pulp temperatures were measured, along with air temperature and airflow rates through the flats (Figure 2). Following all cooling tests, samples were taken for initial quality assessment and the remaining flats were stored in the cold room and sampled after 7 days.

Table 1. Clamshell types used in the study.

1-Pound Clamshell Types

2-Pound Clamshell Types

1

Highland 116

1

Highland 132

2

Pactiv 977z

2

Peninsula H9360

3

Peninsula H7357

3

Peninsula 3130170

4

Peninsula H7356-4 (raised bottom)

5

Peninsula 85035

figure 1

Figure 1. Four flats containing the same clamshell type were first cooled in identical, small-scale forced-air coolers, each with four-flat capacity (left). Later tests were conducted for each 1-lb clamshell type, with two flats, end-to-end from outside to inside using the commercial forced-air cooler (right). Blue arrows indicate direction of airflow.

figure 2

Figure 2. Top view of a pallet layer, showing location of flats for three clamshell types (A, B, C) and direction of airflow across the flats, from outside to inside of the forced-air tunnel.

Results:

Results for cooling studies for the 1-lb clamshell types were similar for both small-scale and commercial coolers; therefore, results summarized here were from the commercial forced-air cooler. Results from cooling the 2-lb clamshell types are from tests with the small-scale unit.

·         Strawberries in 1-lb clamshells reached 7/8 Cooling over a wide range of times; those at the outside of the pallet (air inlet) cooled about twice as fast as those on the inside (air outlet), ranging from 35 minutes to 88 minutes (Table 2).

·         Fruit cooled in 2-lb clamshells had similar results, although 7/8 Cooling Times were slightly longer, 43 to 89 minutes (Table 3).

·         Firmness decreased about 20% after 7 days of storage at 34oF, but uniformly between clamshell types (Tables 4, 6).

·         Soluble solids content and total titratable acidity remained fairly constant.

·         Incidence of bruising increased during 7 days of storage; the main causes were sidewall ribs and raised clamshell bases (Tables 5, 7).

·         Strawberries packed in 2-lb clamshells had more bruising than those in 1-lb containers (Figure 3).

Table 2. Mean 7/8 Cooling Times for 1-lb clamshell containers in small-scale cooler.

7/8 Cooling Time (minutes)

Highland 116

Pactiv 9772

Peninsula H7356-4

Peninsula H7357

Peninsula 85035

Inlet mean*

35

39

49

38

40

Outlet mean

71

83

88

87

76

*Four temperatures/mean.

Table 3. Mean 7/8 Cooling Times for 2-lb clamshell containers in small-scale cooler.

 

7/8 Cooling Time (minutes)

Peninsula H9360

Pactiv A9794

Highland 132

Inlet mean*

43

56

65

Outlet mean

87

89

84

*Four temperatures/mean.

Table 4. Selected quality parameters for fruit in 1-lb clamshell containers, initial and after commercial cooling plus 7 days storage at 34oF.

 

External Colorz

Firmness (Newton/mm)

Soluble Solids Content (oBrix)

Total Titratable Acidity (%)

Clamshell type

L*

Chroma*

hue*

Initial

33.7

48.3

30.2

3.5

5.4

0.8

After 7 days

34.2

44.4

28.0

2.6

5.4

0.8

zL*= Lightness (0=black and 100= white); C*= Chroma Value (higher values = more saturation); hue* angle (0°=red, 90°=yellow).

Table 5. Bruising and cuts for fruit in 1-lb clamshells after commercial cooling plus 7 days storage at 34oF.

  

Bruising (%)

Fruit location

Bruise sizez

Highland 116

Pactiv 9772

Peninsula H7357

Peninsula H7356-4

Peninsula 85035

Fruit-to-fruit

small

4.11

0.60

4.62

0.00

0.00

medium

0.00

0.00

0.00

0.00

0.00

large

17.81

17.37

20.00

30.65

36.51

Top

small

1.37

0.60

1.54

0.00

0.00

medium

0.00

0.00

0.00

0.00

0.00

large

1.37

1.20

1.54

0.00

0.00

Bottom

small

2.74

3.59

4.62

1.61

3.17

medium

0.00

0.00

0.00

0.00

0.00

large

0.00

2.40

3.08

12.90

7.94

Side

small

0.00

0.00

0.00

0.00

0.00

medium

0.00

0.00

0.00

0.00

0.00

large

1.37

0.00

0.00

1.61

4.76

 

Cuts from vent (%)

Top

small

0.00

0.00

0.00

0.00

0.00

medium

0.00

0.00

0.00

0.00

0.00

large

0.00

0.00

1.54

0.00

0.00

Bottom

small

1.37

0.00

0.00

0.00

0.00

medium

0.00

0.00

0.00

0.00

0.00

large

1.37

0.60

0.00

3.23

0.00

Side

small

2.74

4.79

1.54

0.00

0.00

medium

0.00

0.00

0.00

0.00

0.00

large

15.07

14.37

6.15

17.74

6.35

 

Total bruising (%)

28.77

25.75

35.38

46.77

52.38

 

Total cuts (%)

20.55

19.76

9.23

20.97

6.35

 

Total fruit

73

167

65

62

63

zBruise sizes, based on visible surface: small=1/4; medium=1/2; large=entire side.

Table 6. Selected quality parameters for fruit in 2-lb clamshells, initial and after small-scale cooling plus 7 days storage at 34oF.

 

External Colorz

Firmness (Newton/mm)

Soluble Solids Content (oBrix)

Total Titratable Acidity (%)

Clamshell type

L*

Chroma*

hue*

Initial

35.1

46.5

29.6

3.3

7.3

0.71

After 7 days

35.4

46.6

29.6

3.0

6.9

0.78

zL*= Lightness (0=black and 100= white); C*= Chroma Value (higher values = more saturation); hue* angle (0°=red, 90°=yellow).

Table 7. Bruising and cuts for fruit in 2-lb clamshells after small-scale cooling plus 7 days storage at 34oF.

  

Bruising (%)

Fruit location

Bruise sizez

Highland 132

Pactiv A9794

Peninsula H9360

Fruit to fruit

small

1.54

1.11

0.00

medium

6.15

0.74

0.90

large

12.82

19.26

22.42

Top

small

3.08

3.70

0.45

medium

2.56

0.37

0.90

large

4.62

2.96

4.04

Bottom

small

7.18

4.44

4.93

medium

4.10

0.74

0.00

large

4.10

3.70

3.14

Side

small

0.00

1.11

1.35

medium

0.51

1.85

0.45

large

0.00

2.96

1.35

Cut from vent (%)

Top

small

4.62

0.74

0.90

medium

1.03

0.37

0.45

large

2.05

0.00

0.45

Bottom

small

4.62

0.37

1.79

medium

6.67

2.96

0.00

large

6.15

2.59

4.04

 

Total bruising (%)

46.67

42.96

39.91

 

Total cuts (%)

25.13

7.04

7.62

 

Total fruit number

195

270

223

figure 3

Figure 3. Examples of: “fruit-to-fruit” compression (left), cut from vent opening (center), and cut from top edge (right), following 7 days storage at 34oF.

References:

Nunes, M.C., J. Brecht, A. Morais, and S. Sargent. 2005. Physicochemical changes during strawberry development in the field compared to those that occur in harvested fruit during storage.  HortTechnology 15:153-156.

Sargent, S., A. Berry, and J. Brecht. 2014. Commercial scale hydrocooling of fresh market strawberry. American Society for Horticultural Science Annual Meeting. http://ashs.confex.com/ashs/2014/webprogram/Paper20160.html

Sargent, S.A., J.K. Brecht and D.J. Huber. 2016. A two-fold approach to extending postharvest quality of Florida strawberries during commercial shipping and handling. Final Report to Florida Strawberry Growers Assn. 37 pp.