Lesson
1
Introduction
Microbiological Safety of Fresh Fruits & Vegetables
Lesson 1 of 4
Supported in part by a
USDA-CSREES grant entitled “Improving Safety of
Complex Food Items using Electron Beam Technology.”
Authors:
Dr. Tom A. Vestal & Dr. Frank J. Dainello: Texas AgriLife Extension Service
Mr. Jeff Lucas: Texas A&M University
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Lesson
1
Objectives
 Consumption patterns and the increase in foodborne disease
from produce.
 Define foodborne disease.
 Describe foodborne infection and foodborne intoxication.
 Identify causes of foodborne disease outbreaks.
 Identify agents of foodborne disease.
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Lesson
1
Per capita (lb) consumption of raw fruits &
vegetables in the U.S. (USDA 1999).
1982
1983
1984
1985
1986
1987
Vegetables
Fruits
1988
0
20
40
60
80
100
120
140
160
FDA, Outbreaks Associated with Fresh Produce, Table lV-2., 2001.
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Lesson
1
Average Servings Consumed
Year
Fruit
Vegetables
1989-1991
1.3
3.2
1994-1996
1.5
3.4
U.S. GAS, Fruits and Vegetables: Enhanced
Federal Efforts to Increased Consumption. 2002
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Lesson
1
Average Servings Consumed
1994
1996
1998
2000
Total Servings
Fruit & Vegetables
3.44
3.43
3.38
3.37
Total Servings
Vegetables
2.06
2.05
2.02
2.02
Total Servings
Fruits
1.05
1.05
1.04
1.00
U.S. GAS, Fruits and Vegetables: Enhanced
Federal Efforts to Increased Consumption. 2002
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Lesson
1
Increased Consumption of Fresh Produce and
the Occurrence of Foodborne Disease
“During the last three decades, the number of
outbreaks caused by foodborne pathogens associated
with fresh produce consumption reported to the
Centers for Disease Control and Prevention has
increased.”
Sivapalasingam et al., Journal of Food Protection.,
Vol 67, No. 10, 2004, pp 2342-2353
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1973 – 1997 Produce-associated
foodborne illness data…
Produce-Associated Foodborne
Illness Data
Outbreaks
Hospitalizations
Illnesses
Deaths
1973 - 1997
190
598
16,058
8
Lesson
1
Produce of
greatest risk…
 Salad
 Lettuce
 Juice
 Melon
Produce as a % of all outbreaks
 Sprouts
 0.7% in the 1970s
 12% in the 1990s
 Berries
Sivapalasingam et al., Journal of Food Protection.,
Vol 67, No. 10, 2004, pp 2342-2353
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Lesson
1
Factors Affecting an Increase in Foodborne
Illness Related to Fresh Fruits & Vegetables.
 Increased consumption of raw
fruits & vegetables.
 Greater consumption of foods not
prepared in the home.
 Increase in popularity of salad bars
(buffets).
 Greater volumes of both intact and
prepared fruits & vegetables.
 Shipments from centralized
locations.
 Distributions over a wider
geographical area.
 Increased global trade.
FDA, Outbreaks Associated with Fresh Produce, 2001
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Lesson
1
Foodborne Disease
Sometimes referred to as food poisoning.
An illness contracted
through the consumption of
contaminated food stuffs
containing agent(s) that
cause an adverse health
reaction.
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Lesson
1
Growing Hazards

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Soil borne microbes
Contaminated soil or irrigation water
Wildlife and bird feces
Improperly composted manures
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Lesson
1
Harvesting Hazards
 Poor personal hygiene
 Human contamination (lack of or
inadequate toilet and hand washing
facilities)
 Unclean harvesting containers and
equipment
 Metal and lubricant contamination
from harvesting equipment
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Lesson
1
Processing Hazards
 Cross contamination of microbes
 Appropriate temperature
 Metal and lubricant contamination from processing
equipment
 Human contamination
 Failure to adequately clean and sanitize
processing equipment at proper intervals
 Use of unapproved and/or non-potable
water supply
 Proper pest and animal control practices and
equipment
 Not using sanitized storage, processing, and
shipping containers
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Lesson
1
Storage and Distribution Hazards
 Temperature conducive to microbe
population growth
 Transportation equipment
contaminated by previous cargo
 Incidental lapses in pest and
animal control effectiveness
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Lesson
1
Preparation Hazards
Kitchen surface contamination
Improper washing of hands and produce
Utensil cross contamination
Lack of proper temperature control
Contamination from other meal
items such as raw meat
 Improper cooking
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Lesson
1
Foodborne Infection
A foodborne disease caused by the
consumption of contaminated foods
containing live microorganisms or
the spores of those microorganisms.
Growth and multiplication of the
microbes or spores must occur in
order to cause disease.
Most bacterial pathogens double in
population every 20 minutes.
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Lesson
1
Foodborne Intoxication
A foodborne disease caused by the
consumption of contaminated foods
containing a chemical agent or
toxin as a by-product of microbial
growth. Consumption of live
microorganisms is not required.
An example of an intoxicant is
Clostridium botulium, found in soil,
affects the nervous system and has
been found in improperly processed
canned foods, potatoes, olives,
spinach, garlic, mushrooms, beets,
asparagus, peppers, beans, and
eggplant.
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Lesson
1
Agents of Foodborne Disease
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Bacterial
Viral
Parasitic
Chemical
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Lesson
1
Examples of Microbiological Agents (Pathogens) of
Foodborne Disease
Listeria monocytogenes
Salmonella
Escherichia coil 0157:H7
Shigella spp.
Clostridium botulinum
Bacterial
Hepatitis A
noroviruses
Viral
Giardia
Cyclospora
Cryptosporidium
Parasitic
Food Safety Guidelines for the Fresh-cut Produce Industry
4th
Ed, IFPA., 2001., P. 17
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Lesson
1
Symptoms of Disease
Foodborne Disease of Bacterial Origin
Acute upper GI nausea,
vomiting
1 – 6 hours
Preformed heat stable toxins of S.
aureus and B. cereus.
Upper small bowel,
watery diarrhea
6 – 72 hours
C. perfringens, V. cholerae, B. cereus
(diarrheal), enterotoxigenic E. coli.
Inflamed lower intestine
(inflammatory ileocolitis)
16 – 72 hours
Salmonella, Shigella, C. jejuni, V.
parahaemolyticus, Yersinia,
enteroinvasive E. coli.
Sensory or motor
neurologic, with or
without diarrhea
1 – 4 days
C. botulinum toxin
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Lesson
1
Pathogens & Spoilage Organisms
Disease:
 Pathogens: Microorganisms that cause disease.
 Spoilage Organisms: Microorganisms that through
growth render food stuffs unsuitable for consumption
due to changes in odor, flavor, color consistencies or
visible presence.
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Lesson
1
Common Spoilage Organisms
Organism
Product
Source
Pseudomonas species
Vegetables
Soil, plant material
Lactic Acid Bacteria
Vegetables
Soil
Molds
Fruits and vegetables
Soil, plant materials
Yeasts
Fruits
Soil
Food Safety Guidelines for the Fresh-cut Produce Industry
4th Ed, IFPA., 2001., P. 17
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Lesson
1
References
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International Fresh-cut Produce Association. 2001. Food Safety Guidelines for the Freshcut Produce Association. 4th. Edition.
Serdula M, Gillespie C, Kettel-Khan L, Farris R, Seymour J, Denny C. Trends in Fruit and
Vegetable Consumption Among Adults in the United States: Behavioral Risk Factor
Surveillance System, 1994-2000. American Journal of Public Health. June 2004. Vol 94, No
6.
Silliker, Inc. 2003. Principles of Food Microbiology Short Course. Huntington Beach, CA.
March, 2003.
Sivapalasingam S, Friedman C, Cohen L, Tauxe R. Fresh Produce: A Growing Cause of
Outbreaks of Foodborne Illness in the United States, 1973 through 1997. Journal of Food
Protection. 2004. Vol 67. No 10. Pp. 2342-2353.
U.S. Food and Drug Administration. CFSAN. 2001. Analysis and Evaluation of Preventive
Control Measures for the Control and Reduction/Elimination of Microbial Hazards on Fresh
and Fresh-Cut Produce. Food and Drug Administration (FDA), Washington, D.C.
U.S. General Accounting Office. 2002. Fruits and Vegetables: Enhanced Federal Efforts to
Increase Consumption Could Yield Health Benefits for Americans. General Accounting
Office (GAO), Washington, D.C.
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Module 1
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