We all know that vegetables lose some of their nutrients by the time they
 are boxed, shipped, stored, and finally arrive in the grocery store. Our
 business wants to prove that fresh picked vegetables are more nutritious than
 store bought. What is the most compelling scientific results and/or evidence
 that proves this. And by how much? In other words, what is the difference in
 nutrient content between fruits and vegetables picked fresh out of the
 garden versus those picked up "fresh" from the grocery store? Please show us
 your search strategy and the specific URLs where we can scientifically
 document that fresh picked vegetables/herbs are more nutritious than store
 bought. We are looking for current, and very credible, statistics and
 scientific results.
    I've searched the USDA Nutrient Database and Nutrient Retention
Database, they were of no help. They compared various types of cooking
and processing methods with "fresh" foods from the grocery store.
    I've looked at studies on frozen foods and they suggest that many
frozen vegetables lose nutrients from the time they're picked to the
time they are processed for freezing. And these frozen foods generally
retain more nutrients (especially Vitamin C, vitamin A, thiamine,
folate, and potassium) than those "fresh" vegetables at the grocery
store. Clearly that suggests that the garden fresh vegetables will
retain more nutrients than the grocery store fresh veggies. But I have
yet to find the specific numbers in an American study. I hope you can
help.

---

Request for Question Clarification by knowledge_seeker-ga on 13 Nov 2003 07:32 PST

Hi deeper,

I've been working on your question for the last hour and now have a
good general sense of the topic and research avenues. I do have some
questions for you.

You said: 

"Our business wants to prove that fresh picked vegetables are more
nutritious than store bought."

Besides a reduction in nutritional content (data for which I am
finding very little) would you also be interested in research that
shows other deficiencies of store-bought vegetables; for example -
that they are more likely to be bruised or broken, have higher
incidence of disease, or are more dehydrated than farm-fresh?

Also, how much weight should I put on your statement, "the specific
numbers in an American study"?  If I find, say, an Australian or
Canadian study, would that be acceptable?

And finally, do you want any information related to fruit? Or should I
focus only on vegetables?

I'm going to work on this for another hour or so this morning, and if
I don't hear from you, I'll renew my lock but put it on hold for a
bit. I don't want to go running too far down the wrong path.

Use the CLARIFY QUESTION button to respond to me so that I will
alerted by email when you do.

Thanks! Looking forward to hearing from you. 

-K~

---

Request for Question Clarification by knowledge_seeker-ga on 13 Nov 2003 11:07 PST

Update:

The good news is, I am finding plenty of research. But, I?m still a
bit worried about my focus, so do need you to clarify.

1 -- If you want me to keep this to US studies only, I?m afraid we
won?t have much to go on.  Most of the actual research papers I?ve
come across are international ? Brazil, UK, Australia, Greece, and
from international organizations like FAO.  I personally think it
would be a mistake to discount these. There is a wealth of information
out there that is not US-based.

2 ? What we?re really dealing with is TIME from the field to the
consumer and TECHNIQUE for packaging, storage, and transport. Those
are the things that differentiate the truly fresh from the
?supermarket fresh.?

Most of the research surrounds the degradation of *specific* nutrients
in *specific* vegetables that take place as a result of *specific*
storage techniques and duration, temperature and light exposure,
handling, cutting and trimming, or packaging methods.

Of course all of these things could affect farm-fresh vegetables as
well. Poorly stored farm vegetables will deteriorate more quickly than
properly stored market vegetables.

Am I to assume that you want studies that compare ?typically? packed
and stored grocery store vegetables to completely unprocessed,
unpackaged, completely fresh (direct from garden to consumer)
vegetables?


3 ? Many of the articles are highly technical in biochemical terms.
I?ll give you an example below. If you aren?t comfortable in this
realm, I may have trouble providing an answer for you.

Effect of acute ingestion of fresh and stored lettuce (Lactuca sativa)
on plasma total antioxidant capacity and antioxidant levels in human
subjects
http://www.ingenta.com/isis/searching/Expand/ingenta?pub=infobike://cabi/bjn/2002/00000088/00000006/art00003


4 ? From what I?ve read, I don?t believe there is going to be a simple
summing up. All of these studies are tightly focused, and the answer
in one case does not seem to be the answer for the other. In other
words, what?s good for the lettuce isn?t necessarily good for the
carrot. :-)


I await your clarification to let me know if we?re on the right track here. 

Thanks ? K~

---

Clarification of Question by deeper-ga on 13 Nov 2003 16:08 PST

Hi Knowledge,

We are quite excited that you have "taken on" this challenging
question. I will try to answer each of your questions/comments
carefully, because the FOCUS of this research is critical.
 
1. Re: your "besides a reduction in ..." question: we will accept data
on bruised, broken etc as a side interest, but since grocery stores
rarely display such produce, the consumer rarely sees it, and thus it
will have little "sales potency" for us as a business trying to prove
that fresh picked vegetables are more nutrious than store bought.

2. Re: your "other couintries than USA" question: again we will accept
other country data as mildly compelling, but certainly not as
compelling to the USA consumer.

3. Re: include fruit data" question: yes, again, as a side line, but
please focus on veggies.

4. Re: your question about "typical packed?: YES, you are to assure
that we want studies that compare ?typically? packed and stored
grocery store vegetables to completely unprocessed, unpackaged,
completely fresh (direct from garden to consumer) vegetables.

5. Re: your point about the "highly technical nature?: we are
comfortable in this realm, although we want to know the bottom line
too (every scientific study, no matter how technical, has a summary of
results").

6. Re: your point about the non-generalizability of results: yes, we
understand that, and are ok with that.

GENERAL answer to your excellent questions: 
as we can both see, this research could veer off into many sidelines.
Please keep in mind always that we are a business trying to find
compelling evidence that fresh veggies are more nutrious than store
bought. Period. Whatever you can find that will bolster our case shall
be helpful to us, and we will pay you the $50. You might end up giving
us alot of "sideline" data, that may or may not be useful to us as a
business. If that is the case, we will pay you based on the
"usefulness" to our sales and marketing efforts. I hope that you
understand that, and can hit a "home run" here for us, because you
seem to have a wonderful grasp of the subject matter, and could
stumble upon some heretofore hidden, but dynamic statistics for
excatly what we are asking for. Go for it! We are cheering you on!

---

Request for Question Clarification by knowledge_seeker-ga on 14 Nov 2003 10:13 PST

FRIDAY UPDATE---------

Hi Deeper,

Wow. Thanks for the cheering section!  Very encouraging!

And thank you for the clarifications. They help a great deal. 

Today I sent an email to someone I know at the USDA (Bob). He
forwarded me to a Nutrient Specialist there. She then forwarded my
email to a Vegetable Specialist. I expect there will be several more
forwards to several more specialists before my email lands right back
on Bob?s desk. At that point, if nothing else, we will have confirmed
that we are, in fact, dealing with a government agency. ;-)

So, while that?s happening, I?ve been slowly amassing individual
research articles to support what we?re looking for, which brings me
to my next question:

Nearly all of the research studies I?ve found provide only ABSTRACTS
for free online. Most do give a summary of the result in the abstract,
but the details of the research aren?t presented. A few of these
provide access to FULL TEXT ARTICLES for a fee (eg $25 for 48 hrs of
access) or by paying a subscription. Most do not. To read these in
full, you?d have to track them down at your local University library.

Will this work for you?

And finally, are we on a deadline here? I ask because, unless the USDA
specialist hands us a nice pretty comparison report this afternoon,
this is going to take quite some time to find, organize, and put
together for you. I?m thinking (taking into account the weekend and my
availability) that I probably won?t be able to wrap this up properly
until late Monday or even Tuesday next week.

If you need it sooner, say so! If I don?t think I can make your
deadline, I?ll pass my work along to another researcher who may be
able to finish the job sooner.

Meanwhile, I will keep you apprised of my progress. 

Keep cheering!

-K~

---

Clarification of Question by deeper-ga on 14 Nov 2003 12:03 PST

Hi Knowledge~

Wow. Thanks for the encouraging update. 

1. We are glad that you are pursuing the "personal specialist" route.
That could be promising.

2. We will totally accept abstracts (as long as the results are
summarized therein). If we like the study enough, we will "buy it."
But the abstract will let us know just how relevant it is. And handing
us abstracts certainly counts toward your payment.

3. There is no deadline here. We would "like" you to be done by
mid-week, but if the process and/or results justify more time, so be
it. Do not hand off your project to another, becasue this is your
baby.

4. if you "over-acheive" and provide us with just the outstanding
statistics we want, we are very open to a nice tip.
 
Keep the deep pursuit!

---

Request for Question Clarification by knowledge_seeker-ga on 18 Nov 2003 06:41 PST

Hi deeper,

Am just checking in with you. I think I've found all there is to be
found, so now it's a matter of sorting it out, making sure it's enough
to support your argument, and then formulating an answer. I expect to
have something for you by the end of today.

I followed up with the USDA..nothing yet. Also have sent 2 more emails
to vegetable experts who stand out in their fields, so to speak. :-)

Will be in touch ..

-K~

---

Request for Question Clarification by knowledge_seeker-ga on 18 Nov 2003 07:02 PST

Oh..and by the way .. if none of these people get back to me, I'll
provide you with all of their contact information so you can follow up
directly.

-K~

Ok deeper, 

Here it is!

This has certainly been quite a project. Good thing I like vegetables!
I?ve tried to first, sum things up for you, and then present you with
the data to support the summary. However, not every point is reflected
in the data. For example, I found a generic reference to "water
soluble vitamins" degrading over time, but little research having to
do with the B vitamins specifically.

I?m confident that overall you?ll find it to be a good argument for your case. 




===============================================================
REASONS FRESH VEGETABLES ARE MORE NUTRITIOUS THAN STORE-BOUGHT 
===============================================================

SUMMARY
-------

From the moment they are harvested, plant matter begins to undergo
senescence -- a genetically regulated process which leads to the death
of cells, organs, or whole organisms.

In plants, senescence is accompanied by structural changes and/or
changes in biochemical and biophysical metabolic properties. This may
involve degradation of proteins, chlorophyll and nucleic acids.

This cell breakdown causes vegetables to cease forming nutritive
chemicals. As a result, they begin to lose nutrients in the form of
water soluble vitamins (B & C), antioxidants, and protein.

For this reason, time from field to consumer and the care of the crop
in between, are the defining variables that differentiate the
nutritive value of farm-fresh vegetables from those bought from
grocery stores.

Also, any type of processing, even minimal, including cutting, slicing
or trimming increases the rate at which vegetables undergo nutritional
and quality deterioration.

Additionally, the more hands (and processes) they pass through on
their way to the consumer, the more likely they are to pick up
contamination such as bacteria.

Finally, because vegetables going to market must be picked earlier in
their development cycle than farm-fresh vegetables, many are harvested
before they achieve maximum nutrient capacity.

 
SPECIFICS
---------

Grocery Vegetables
Time from Field to Consumer: 5 -14 days 


During that time, the following occurs:  

     1. Vitamin C (ascorbic acid / ascorbate) degrades* 

     2. Degradation B vitamins
     .....B1 /thiamine; 
     .....B2 /riboflavin;
     .....B3 /niacin;
     .....B5 /pantothenic acid;
     .....B6 / pyridoxine
     .....B9 / Folate and folic acid (2 forms of B9)
   

     3. Loss of Antioxidants -- 

     .....Monoterpenes: limonene, carvone, carveol; 
     .....Diterpenes: retinoids
     .....Tetraterpenes: carotenoids like alpha- and beta-carotene,
          lutein, lycopene zeaxanthine, cryptoxanthine


     Also mentioned:  Glucoraphanin, the glucosinolate precursor 
                      of anticancer isothiocyanate sulforaphane


     4. Decrease in protein 

     5. Potential for human contamination via packaging and handling
 
     6. Increase in some natural toxins 
        (eg: synthesis of glycoalkaloids in potatoes)




*Exceptions ?

Tomatoes and red sweet peppers picked unripe, increase vitamin A as
they ripen off the vine, but decrease in Vitamin C.


=================================
PEER REVIEWED PUBLISHED RESEARCH
=================================

Only the first study below actually compares nutrients between farm
fresh and simulated commercial storage and transport.

Most illustrate the breakdown of specific nutrients in specific
vegetables over time. However, the thing to remember is that every
time they refer to storage or processing, the researchers have to
start with a baseline control ? that is *fresh-picked* produce. They
can?t begin with a product that has already been transported and
stored for several days. The results would be meaningless.

For example, I?ve been to the USDA research farms in Beltsville
Maryland. They have acres of fields and miles of greenhouses where
they maintain these crops for testing purposes.

So, in reality, to be valid, all of these studies should be comparing
?fresh? produce to that which has been stored, transported, or
otherwise processed as it would be for retail sale.


---------------------

"Total aliphatic and indole glucosinolates, phenolic compounds
(flavonoids and hydroxycinnamoyl derivatives), and vitamin C contents
were evaluated in freshly harvested broccoli (Brassica oleracea L.,
var. italica, cv. Marathon) inflorescences. These were film-wrapped
and stored for 7 days at 1 degrees C to simulate a maximum period of
commercial transport and distribution.

"Results showed major losses at the end of both periods, in comparison
with broccoli at harvest. Thus, the respective losses, at the end of
cold storage and retail periods, were 71-80% of total glucosinolates,
62-59% of total flavonoids, 51-44% of sinapic acid derivatives, and
73-74% caffeoyl-quinic acid derivatives. Slight differences in all
compound concentrations between storage and retail sale periods were
detected. Distribution and retail periods had minimal effects on
vitamin C."


HEALTH-PROMOTING COMPOUNDS IN BROCCOLI AS INFLUENCED BY REFRIGERATED
TRANSPORT AND RETAIL SALE PERIOD.
Vallejo F, Tomas-Barberan F, Garcia-Viguera C.
Laboratorio de Fitoquimica, Departamento de Ciencia y Tecnologia de
los Alimentos, CEBAS-CSIC, P.O. Box 4195, E-30080 Murcia, Spain.

ABSTRACT
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12720387&dopt=Abstract

PURCHASE - $25
http://pubs.acs.org/emeta/AcsLogin?url=%2FUADB%2Fxppview%2Fcgi-bin%2Farticle.cgi%2Fjafcau%2F2003%2F51%2Fi10%2Fpdf%2Fjf021065j.pdf&mode=login

 
--------------------

"Being highly unsaturated, carotenoids are susceptible to
isomerization and oxidation during processing and storage of foods.
Isomerization of trans-carotenoids to cis-carotenoids, promoted by
contact with acids, heat treatment and exposure to light, diminishes
the color and the vitamin A activity of carotenoids."

CHANGES IN CAROTENOIDS DURING PROCESSING AND STORAGE OF FOODS. 
Rodriguez-Amaya DB.
Arch Latinoam Nutr. 1999 Sep;49(3 Suppl 1):38S-47S.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10971842&dopt=Abstract

[abstract only]


--------------------


"The present study investigated whether storage under
modified-atmosphere packaging (MAP) affected the antioxidant
properties of fresh lettuce (Lactuca sativa)...

"Eleven healthy volunteers (six men, five women) consumed 250 g fresh
lettuce, and blood was sampled before (0 h) and 2, 3 and 6 h after
consumption...

"The protocol was repeated 3 d later with the same lettuce stored at
5°C under MAP conditions (O2?N2 (5:95, v/v))...

"Results showed that after ingestion of fresh lettuce, plasma total
radical-trapping antioxidant potential (TRAP), measured as area under
the curve, was significantly higher ?. THAN THE VALUE OBTAINED WITH
MAP-STORED LETTUCE"

EFFECT OF ACUTE INGESTION OF FRESH AND STORED LETTUCE LACTUCA SATIVA)
ON PLASMA TOTAL ANTIOXIDANT CAPACITY AND ANTIOXIDANT LEVELS IN HUMAN
SUBJECTS
British Journal of Nutrition,   December 2002, vol. 88, no. 6, pp. 615-623(9)
http://www.ingenta.com/isis/searching/Expand/ingenta?pub=infobike://cabi/bjn/2002/00000088/00000006/art00003

[Full text for purchase. $16.36 ]

-------------

"Beta-carotene acts as a pro-vitamin A or anti-cancer compound.
Carrots contain the highest amount of beta-carotene of common fruits
and vegetables, but each year 25% of carrot production is lost in the
U.S. during processing and storage...

"...This article is a review of the most recent studies concerning
beta-carotene retention in carrots during processing and storage.

"...The trans form of beta-carotene in carrots is replaced by the cis
form during processing. Beta-Carotene can be extracted from carrots,
but the half-life of free beta-carotene is reduced to 2 d in the juice
extract at room temperature..."

Crit Rev Food Sci Nutr. 1998 Jul;38(5):381-96
PRESERVATION OF BETA-CAROTENE FROM CARROTS.
Desobry SA, Netto FM, Labuza TP.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9704189&dopt=Abstract

[abstract only]

--------------------

"Fresh Lima beans were subjected to various combinations of handling
factors, including storage time and temperature, air during storage,
water during preparation, hulling, and preparation method, to
determine their effects on ascorbic acid, thiamin, and carotene
content.

Longer storage time and higher storage temperature resulted in
significant reduction in ascorbic acid. Bruising, such as that
occurring when beans are mechanically hulled, caused significant
losses of both carotene and ascorbic acid."


J Am Diet Assoc. 1976 Dec;69(6):640-4
EFFECTS OF STORAGE AND HANDLING ON VITAMINS IN FRESH LIMA BEANS.
Head MK, Giesbrecht FG.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=993537&dopt=Abstract

[abstract only]

---------------

"...the effect of traditional processing practices on the retention of
ascorbic acid, riboflavin and thiamine were studied using amaranth,
cowpea, peanut, pumpkin and sweetpotato leaves

"...sun/shade drying and storing in ventilated containers resulted in
a significant?decrease in ascorbic acid, riboflavin and thiamine for
all vegetables"

J Am Diet Assoc. 1976 Dec;69(6):640-4
EFFECTS OF STORAGE AND HANDLING ON VITAMINS IN FRESH LIMA BEANS.
Head MK, Giesbrecht FG.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8833430&dopt=Abstract

[abstract only]
----------------------


"The effects of post-harvest and packaging treatments on glucoraphanin
(4-methylsulfinylbutyl glucosinolate), the glucosinolate precursor of
anticancer isothiocyanate sulforaphane [4-methylsulfinylbutyl
isothiocyanate], were examined in broccoli (Brassica oleracea var.
italica) during storage times. The results showed that at 20 degrees
C, 55% loss of glucoraphanin concentration occurred in broccoli stored
in open boxes during the first 3 days of the treatment and 56% loss
was found in broccoli stored in plastic bags by day 7."


THE EFFECT OF POST-HARVEST AND PACKAGING TREATMENTS ON GLUCORAPHANIN
CONCENTRATION IN BROCCOLI (BRASSICA OLERACEA VAR. ITALICA).

Rangkadilok N, Tomkins B, Nicolas ME, Premier RR, Bennett RN, Eagling
DR, Taylor PW.

ABSTRACT
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12452663&dopt=Abstract

ARTICLE [48 hr web access - $25]
http://pubs.acs.org/emeta/AcsLogin?url=%2FUADB%2Fxppview%2Fcgi-bin%2Farticle.cgi%2Fjafcau%2F2002%2F50%2Fi25%2Fpdf%2Fjf0203592.pdf&mode=login


--------------

"The effect of modified atmosphere packaging (MAP) and cooking on the
flavonoids and vitamin C content (ascorbic + dehydroascorbic acid; AA
+ DHAA) of fresh-cut spinach was evaluated...

"A decrease in the total antioxidant activity was observed during
storage, particularly important in MAP-stored spinach."

EFFECT OF POSTHARVEST STORAGE AND PROCESSING ON THE ANTIOXIDANT
CONSTITUENTS (FLAVONOIDS AND VITAMIN C) OF FRESH-CUT SPINACH.
Gil MI, Ferreres F, Tomas-Barberan FA.

ABSTRACT
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10794612&dopt=Abstract

PURCHASE $25
http://pubs.acs.org/emeta/AcsLogin?url=%2FUADB%2Fxppview%2Fcgi-bin%2Farticle.cgi%2Fjafcau%2F1999%2F47%2Fi06%2Fpdf%2Fjf981200l.pdf&mode=login


----------------

"...The ascorbate content declined rapidly in broccoli (Brassica
oleracea L. var. italica) florets, but not in the stem tissue, during
post-harvest senescence...it was observed that mRNA levels of
chloroplastic APX, BO-sAPX and BO-tbAPX, had decreased by 12 h after
harvest in broccoli florets, suggesting that the active oxygen species
(AOS) scavenging system in chloroplasts was largely abolished in
florets during the early hours of the post-harvest period."


ASCORBATE METABOLISM IN HARVESTED BROCCOLI 
Received 7 July 2003; Accepted 21 July 2003
Fumie Nishikawa*,1, Masaya Kato3, Hiroshi Hyodo2, Yoshinori Ikoma3,
Minoru Sugiura3 and Masamichi Yano3

http://jxb.oupjournals.org/cgi/content/abstract/54/392/2439


[Full text available - 24 hours for US $19.00.]

--------------------

Harvest-induced senescence of broccoli results in tissue wilting and
sepal chlorosis. As senescence progresses, chlorophyll and protein
levels in floret tissues decline and endo-protease activity (measured
with azo-casein) increases

IDENTIFICATION OF DEHYDRATION-RESPONSIVE CYSTEINE PROTEASES DURING
POST-HARVEST SENESCENCE OF BROCCOLI FLORETS
Simon A. Coupe2,, Ben K. Sinclair, Lyn M. Watson, Julian A. Heyes and
Jocelyn R. Eason3,

http://jxb.oupjournals.org/cgi/content/abstract/54/384/1045


[Full text available - 24 hours for US $19.00.]

-----------------

* I?m not clear on whether or not this study began with fresh produce. 


"The objective of this work was to conduct a systematic, comparative
kinetic study of Vitamin C deterioration for four different frozen
green vegetables, in the whole temperature range occuring in the real
distribution chain of frozen foods.

In all cases, Vitamin C loss followed apparent first order kinetics.
Spinach showed a significantly faster nutritional degradation at all
temperatures (50% loss in 2 months at -15oC), followed by green beans
and green peas, whereas, in okra, Vitamin C was well retained."

COMPARATIVE KINETIC STUDY AND EVALUATION OF NUTRIENT DEGRADATION
DURING DISTRIBUTION AND STORAGE OF FOUR FROZEN GREEN VEGETABLES
http://ift.confex.com/ift/2002/techprogram/paper_13520.htm

[abstract only]

------------------

"Fresh peppers (Capsicum annuum L., variety California) in their green
and red ripe stages were stored at 20 degrees C for 7 and 19 days to
determine the effects of storage on whole fruit antioxidant capacity
(TAA) and ascorbate (ASC) content, as well as on some antioxidant
enzyme activities, such as catalase (CAT), superoxide dismutase (SOD),
and those of the ASC-glutathione cycle.

"...TAA, as well as the ASC content, was higher in red peppers than in
green, and storage increased the ASC in both green and red fruits."

ANTIOXIDANT SYSTEMS AND THEIR RELATIONSHIP WITH THE RESPONSE OF PEPPER
FRUITS TO STORAGE AT 20 DEGREES C.
Jimenez A, Romojaro F, Gomez JM, Llanos MR, Sevilla F.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=14518958&dopt=Abstract

[abstract only]

----------------------------

"...Concentrations of total ascorbate dropped significantly in spinach
leaves following detachment, regardless of the storage atmosphere"


THE EFFECTS OF ETHYLENE, DEPRESSED OXYGEN AND ELEVATED CARBON DIOXIDE
ON ANTIOXIDANT PROFILES OF SENESCING SPINACH LEAVES

D. Mark Hodges1 and Charles F. Forney 
Atlantic Food and Horticulture Research Centre, Agriculture and
Agri-Food Canada, 32 Main Street, Kentville, Nova Scotia, B4N 1J5
Canada

http://jxb.oupjournals.org/cgi/content/full/51/344/645

[full text]

-----------------------
NATURAL TOXIN ISSUES
-----------------------

"Potatoes contain antinutritional and potentially toxic compounds ??
In this overview, we describe ?reported changes in glycoalkaloid
content of fresh and processed potatoes during storage, ?. Reducing
the glycoalkaloid content of potatoes will provide a variety of
benefits extending from the farm to processing, shipping, marketing,
and consumption of potatoes and potato products."


POSTHARVEST CHANGES IN GLYCOALKALOID CONTENT OF POTATOES.
Friedman M, McDonald GM.
Western Regional Research Center, U.S. Department of Agriculture,
Albany, California 94710, USA.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10335373&dopt=Abstract

[abstract only]



---------------------------
FOOD CONTAMINATION ISSUES
---------------------------

Locally produced farm-fresh vegetables may be safer (and thus more
nutritious) than store-bought vegetables, since *some* food-borne
pathogens originate in internationally grown crops.

The FDA states: 

Cyclospora cayetanensis

"...recently, it has been associated epidemiologically in the USA and
Canada with foodborne outbreaks. Items of fresh produce, mostly
imported, appear to be the vehicles - mesclun lettuce, basil, and
raspberries."
 

Also, the FDA notes some of the primary barriers to achieving their
?Healthy People 2000? objectives include:

"The increasing proportion of food imported from other countries.?

"The introduction of new food processing and packaging technologies.
For example, the use of modified atmosphere to prolong the shelf-life
and maintain the quality of vegetables may enable anaerobic organisms,
including human pathogens, to proliferate."

"The difficulty of convincing food workers that they need to be
concerned about food safety. A study of convenience store managers and
employees in Michigan showed that they tend to overestimate their
knowledge. Actual sanitary conditions in stores were closely
associated with actual knowledge."

"The difficulty of motivating all those who prepare food to follow
proper food preparation practices."


HEALTHY PEOPLE 2000: STATUS REPORT
FOOD SAFETY OBJECTIVES
http://www.foodsafety.gov/~dms/hp2k.html


More information:

FDA: Guide to Minimize Microbial Food Safety Hazards for Fresh Fruits
and Vegetables
http://www.cfsan.fda.gov/~dms/prodguid.html



-----------------

This I?m not sure is useful, but will leave it in and you can decide. 
  

The following studies illustrate the danger of Hepatitis A virus being
transmitted from food handlers to consumers. Naturally, the more food
handlers involved in the processing of vegetables, the higher the
likelihood of contamination.

However, I haven?t been able to confirm where in the handling process
contamination takes place. It may in fact be at the farm. And, I
haven?t confirmed whether grocery store produce is an issue, or
whether the concern is more with restaurants. This may be a whole
other research project, but wanted to at least let you know about it.


THE SURVIVAL OF HEPATITIS A VIRUS IN FRESH PRODUCE.
Croci L, De Medici D, Scalfaro C, Fiore A, Toti L.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11883673&dopt=Abstract

[abstract only]


Applied and Environmental Microbiology, July 2000, p. 2759-2763, Vol. 66, No. 7

CONTAMINATION OF FOODS BY FOOD HANDLERS: EXPERIMENTS ON HEPATITIS A
VIRUS TRANSFER TO FOOD AND ITS INTERRUPTION
S. Bidawid,1,* J. M. Farber,1 and S. A. Sattar2
http://aem.asm.org/cgi/content/full/66/7/2759?view=full&pmid=10877765

[full text]


====================
SUPPORTING ARTICLES 
====================

Not necessarily referenced or peer reviewed, but most from reputable sources.  


---------------------

"While the fat soluble vitamin content of food tends to be quite
stable and resists degradation, water soluble vitamins are fragile and
easily destroyed by lengthy storage, high temperatures, processing,
and cooking.

"Fruits and vegetables contain their highest level of nutrients when
they are harvested at full ripeness and eaten soon thereafter, with
only minimal processing. Thus, the most nutritious produce consists of
homegrown fruits and vegetables picked at full maturity (avoid picking
prematurely and allowing them to ripen off the vine) and eaten
immediately.

"Fresh" supermarket produce does not always fit this description as it
is often picked before fully ripe, shipped long distances, and stored
under poor conditions.

"A cool, dark place is generally best since vitamin degradation
accelerates at higher temperatures and several of the water soluble
vitamins, riboflavin and vitamin C in particular, are very light
sensitive"


COLUMBIA UNIVERSITY COLLEGE OF PHYSICIANS & SURGEONS
MEDICAL GUIDE: The Basics of Good Nutrition - Vitamins
http://cpmcnet.columbia.edu/texts/guide/hmg05_0003.html#5.2


---------------------------
Postharvest Issues for Protected Agriculture Production
Postharvest Handling and Monitoring of Quality for Vegetables Produced
in Greenhouses in Hot, Arid Climates
Wilfried H. Schnitzler

Institute for Vegetable Science, Technische Universit ät München, Freising, Germany

"Postharvest losses include physiological changes and vitamin C
degradation of vegetables; these may be affected by postharvest
temperature and respiration rate. ?. Respiration rate is a good index
of the potential postharvest life of a vegetable since it increases
with the rate of deterioration.

"...Temperature, relative humidity, gases, micro-organisms and insects
are the most important environmental factors that affect water loss
from vegetables.."

POSTHARVEST HANDLING AND MONITORING OF QUALITY FOR VEGETABLES PRODUCED
IN GREENHOUSES IN HOT, ARID CLIMATES
http://www.icarda.cgiar.org/APRP/html/Publications/Right/PrWS/PostHarvest.pdf

------------------

"Qualitative losses include losses in (a) edibility, (b) nutritional
quality, (c) caloric value, and (d) consumer acceptability of
products.

.... The rate of biological deterioration depends on various
environmental (external) factors including temperature, relative
humidity, air velocity, and concentrations of ethylene, oxygen, and
carbon dioxide."

POSTHARVEST LOSSES OF HORTICULTURAL PERISHABLES
http://www.iita.org/info/ph2/news2.htm

--------------------

"...Much of the green produce available in the supermarket or
greengrocers is far from fresh. It is not uncommon for produce, after
harvesting, to spend several days being sorted and packaged. Once
placed in a refrigerated truck, the hapless vegetable may spend
several more days on a journey to a distribution centre, where yet
more time may be spent stored in a refrigerator. When it finally makes
its way through a supermarket checkout, the ?fresh? vegetable or fruit
may have spent a week or more in storage from the time it was picked.
Cold storage, fluctuations in light and temperature, and display
beneath supermarket lights, each cause degradation and breakdown of
nutrients.

"...Tests show that green beans, for example, lose 40 percent of their
vitamin C content in the first two days after harvesting, and within
three days of harvesting, a whopping 58 percent of vitamin C has gone.
Often foods are harvested before they are fully ripe, with the
expectation that further ripening will occur after harvest."

FRESH, FROZEN OR CANNED? 
By: Lynda Wharton
http://www.sculptforwomen.com/index.cfm?fuseaction=article&articleId=27

--------------


This website discusses many of the major vegetable crops, and while
not giving specific nutrient information, does discuss the loss of
some nutrients in some vegetables as a result of improper storage over
time. I?ve provided some sample excerpts below.


OREGON STATE UNIV. Commercial Vegetable Production Guides
http://oregonstate.edu/Dept/NWREC/vegindex.html


ASPARAGUS
"...Fresh asparagus is highly perishable and deteriorates rapidly at
temperatures above 40 F. ? In addition to general deterioration, spear
growth, loss of tenderness, loss of flavor, loss of vitamin C, and
development of decay take place at moderately high temperatures."

ASPARAGUS - ASPARAGUS OFFICINALIS 
http://oregonstate.edu/Dept/NWREC/asparagu.html


BEETS (GREENS)
"Research has shown that kale packed in polyethylene-lined crates and
protected by crushed ice keeps in excellent condition for 3 weeks at
32 F but only 1 week at 40 F and 3 days at 50 F. Vitamin content and
quality are retained better when wilting is prevented."

BEETS
http://oregonstate.edu/Dept/NWREC/beetch.html#storage



BROCCOLI
"...Broccoli is highly perishable, and it is usually stored for only a
brief period as needed for orderly marketing. Broccoli should be
hydrocooled or packed in ice immediately after harvest and kept at 32
F to maintain good salable condition, fresh green color, and vitamin C
content. ? The respiration rate of freshly harvested broccoli is very
high - comparable to that of asparagus, spinach, or sweet corn."

BROCCOLI
http://oregonstate.edu/Dept/NWREC/broc-pr.html

--------------

This Q & A illustrates the increase in Vitamin A and the decrease in
Vitamin C in tomatoes as they ripen from green to red.


"Q: At what stage of development does fruit contain the most nutrients?? 

"I found no specific information on the rate of degradation of
nutrients in tomato or peach, but in general, the fresher the better.
However a couple of points should be mentioned..."

"...some specifics for red and green tomato provided by the
Cooperative Extension Service (at the Univ. of Rhode Island). Their
source was: Pennington, J.A.T. (1989). Food values of portions
commonly used.

			GREEN	                RED
           Vitamin A (IU)	789		1394
           Vitamin C (mg)	29		22
           Vitamin B1 (mg)	0.07		0.07


AT WHAT STAGE OF DEVELOPMENT DOES FRUIT CONTAIN THE MOST NUTRIENTS?
http://www.madsci.org/posts/archives/dec97/875556095.Bt.r.html

-----------------

This very long in-depth FAO report contains a wealth of information on
post harvest losses in vegetables. While they make reference to
vitamin and other nutrient losses, I found no specific data. However,
I?ve pulled a couple of relevant quotes for you here --


CHAPTER 1. FRUITS AND VEGETABLES: AN OVERVIEW ON SOCIO-ECONOMICAL AND
TECHNICAL ISSUES

"Physiological deterioration of fruits and vegetables refers to the
aging of products during storage due to natural reactions.
Deterioration caused by biochemical or chemical agents refers to
reactions, of which intermediate and final products are undesirable.
These can result in significant loss of nutritional value.."



CHAPTER 3. GENERAL CONSIDERATIONS FOR PRESERVATION OF FRUITS AND VEGETABLES


"...Because MP [minimally processed ] refrigerated products can be
raw, the cells of the vegetative tissue may be alive and respiring (as
in fruits and vegetables), and biochemical reactions can take place
that lead to rapid senescence and/or quality changes. ? in most cases,
minimally processed foods are more perishable than the unprocessed raw
materials from which they are made."

HANDLING AND PRESERVATION OF FRUITS AND VEGETABLES BY COMBINED METHODS
FOR RURAL AREAS
TECHNICAL MANUAL
FAO Agricultural Services Bulletin 149
FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS
Rome, 2003
http://www.fao.org/DOCREP/005/Y4358E/y4358e00.htm#Contents



===============
CONTACTS
===============

I?ve contacted the following organizations and individuals, but have
received no information from them.

So that you may follow up, here?s the info for you. 

-------------
Email sent to USDA: 

Rena Cutrufelli rcutrufelli@rbhnrc.usda.gov 
http://www.ars.usda.gov/pandp/people/people.htm?personid=1226

She forwarded it to ?vegetable specialist?:

David ??
hni01dh@libra.rbhnrc.usda.gov

No reply.


-------------------

These folks have a number of post-harvest specialists. Since some have
no email, I sent my request to general delivery--

UC DAVIS - DEPARTMENT OF VEGETABLE CROPS AND WEED SCIENCE PROGRAM
http://veghome.ucdavis.edu/contact.htm

FACULTY
http://veghome.ucdavis.edu/faculty.htm


University of California, Davis
One Shields Ave.
Davis, CA 95616
Telephone: (530)752-0516
Fax: (530)752-9659

General Info Email: info@vegmail.ucdavis.edu
 
Received reply today:

"I am forwarding your request to the Postharvest Research and
Information Center. You should also check the following web site:
http://groups.ucanr.org/UC_GAPs/index.cfm

Check the "documents" page."

Mary E. (Kitty) Schlosser
Vegetable Research & Information Center
University of California
One Shields Ave.
Davis, CA 95616
Phone: 530-752-1748
Fax: 530-752-9659
Email: meschlosser@ucdavis.edu

Web: vric.ucdavis.edu

---------------------------

So, that?s what I?ve done. I?m going to leave you to digest everything
I?ve given you. I understand it may take awhile, that?s fine. Let me
know if you need clarification of any of the points.

As I said, this has been a huge undertaking, but I?ve sure learned a
lot. Kind of makes me look at that store-bought broccoli and those
pre-peeled carrots and wonder why I even bother ? maybe we should
arrange with the editors for me to be paid in produce.  ;-)  I?ve got
a craving for a good fresh salad right about now!

Let me know if you need anything ?

-K~

-------------
search terms
-------------

where to begin?  :-)

I pretty much just worked PubMed to death. I didn?t think to save all
of my searches from there, but this is a partial sampling of a couple
hour?s work. The last number in the column refers to the number of
returns for the search that I then worked through.


#18 Search "farm to fork" 18:45:12 16 
#12 Search vegetable contamination bacteria 18:41:19 253 
#10 Search vegetable contamination 18:37:18 1573 
#9 Search farm vegetable HAV 18:12:06 1 
#6 Search virus vegetable HAV 18:10:57 9 
#3 Search virus vegetables HAV

#34 Search spinach storage 18:55:53 57 
#33 Search riboflavin spinach storage 18:55:48 0 
#31 Search riboflavin degradation spinach 18:54:33 47 
#30 Search riboflavin degradation vegetable 18:54:16 95 
#26 Search thiamine degradation vegetable 18:52:20 55 
#25 Search thiamine degradation  18:51:35 5475 
#23 Search thiamine vegetable 18:50:09 119 
#22 Search thiamine breakdown vegetable
#43 Search "farm gate" 17:16:09 11 
#41 Search "harvest induced" 17:11:44 7 
#40 Search "field to consumer" 17:11:15 0 
#39 Search "farm to consumer" 17:10:48 133 
#38 Search "ascorbate metabolism" vegetable storage 17:09:51 8 
#35 Search "ascorbate metabolism" vegetables 17:08:31 200 
#34 Search "ascorbate metabolism" 17:08:08 6634 
#32 Search ascorbate metabolism 17:04:17 6634 
#17 Search "post harvest"  17:03:27 200 
#16 Search "post harvest" nutrient 14:43:21 2 
#14 Search "field to consumer" nutrient 14:43:04 0 
#13 Search "field to store" nutrient 14:42:58 0 
#12 Search "farm to store" nutrient 14:42:51 0 
#6 Search "fresh vegetables" 14:38:54 169 
#2 Search "fresh cabbage" 14:37:53 104 
#1 Search "fresh carrots"

---

Request for Answer Clarification by deeper-ga on 20 Nov 2003 10:38 PST

Hi great researcher,

We have received your new research, and want to thank you! It will
take us a little time to digest all this... maybe a day or two. Then
we will "rate the answer" and pay you! Again, thank you for the deep
research.

---

Clarification of Answer by knowledge_seeker-ga on 26 Nov 2003 07:55 PST

Hi deeper!

Thank you for the rating and nice tip. 

I'm sorry the results weren't as dazzling as you had hoped. Yes, there
seems to be a void in the research when it comes to measuring the
difference in nutritional value between farm-fresh and market-fresh
vegetables. I had hoped that the material I provided would give you
enough to build your case by way of examples since a nice clean
summarizing chart wasn't to be found.

I would strongly suggest that you follow up personally with both the
USDA contact and the folks at UC Davis. Neither ever did get back to
me, but I suspect if you deal with them directly you will have better
luck getting them to hand you some more concrete data.

Best of luck with your veggie venture! 

-K~

Thank you for your strong effort. The results were not dazzling, but
that seems to be because there just isn't much on this subject.
Nevertheless, we are rating this a 5 star due to the effort and
persistence, and especially because you went beyond just a web-based
search (ie, actually called contacts, etc). Much appreciation.

The research completed was worth hundreds times more than paid. $50
should have got the 'business' posing the question a couple of links
to some newspapers reports. Not the intense and scientific reply
given. Google Answers is really devaluing the work done by researchers
if 'businesses' are encouraged to believe that several days of
research is worth only $50. The tip should have been $450, and that
would still be a con. If you really are a business pay a decent
research rate.