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Pathogens Commonly Associated with Fresh

Produce: How Can They Be Controlled? David Nyachuba, Ph.D.David Nyachuba, Ph.D.

Assistant Professor, Department of Nutrition, UMass–AmherstAssistant Professor, Department of Nutrition, UMass–AmherstDirector of UMass Extension Food Safety Education ProgramDirector of UMass Extension Food Safety Education Program

Good Agricultural Practices (GAPs) Food Safety TrainingGood Agricultural Practices (GAPs) Food Safety Training

March 4, 2009March 4, 2009

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Food Safety – Everyone Can Play A Role GrowersGrowers Fresh produce handlers:Fresh produce handlers:

packerspackers distributors distributors

Food processors, wholesalers, Food processors, wholesalers, distributorsdistributors

Retailers including food serviceRetailers including food service ConsumersConsumers

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Hazards Occur:

GrowingGrowing HarvestingHarvesting ProcessingProcessing StorageStorage DistributionDistribution RetailingRetailing Final PreparationFinal Preparation

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Definitions MicroorganismMicroorganism

Small, living organismSmall, living organism PathogenPathogen

Illness-causing microorganismIllness-causing microorganism HazardHazard

An agent that is reasonably likely to cause illness or injury An agent that is reasonably likely to cause illness or injury in the absence of controlin the absence of control

ContaminationContamination When harmful microorganisms, chemicals or foreign When harmful microorganisms, chemicals or foreign

objects get into food, either naturally or by accidentobjects get into food, either naturally or by accident Cross-contaminationCross-contamination

Microorganisms are transferred from one food or surface Microorganisms are transferred from one food or surface to anotherto another

Foodborne illnessFoodborne illness Illness carried or transmitted to people by foodIllness carried or transmitted to people by food

Foodborne outbreakFoodborne outbreak Incident in which Incident in which two or more peopletwo or more people experience the same experience the same

illness after illness after eating the same foodeating the same food

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Types of Food Safety Hazards

1.1. Microbial HazardsMicrobial Hazards

2.2. Chemical HazardsChemical Hazards

3.3. Physical HazardsPhysical Hazards

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Foodborne Illness Statistics cases: 76 million illnesses in the U.S. cases: 76 million illnesses in the U.S.

each yeareach year hospitalizations: 325,000 per yearhospitalizations: 325,000 per year deaths: 5,000 per yeardeaths: 5,000 per year

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Cost of Foodborne Illness Cost: $10-83 billion Cost: $10-83 billion

each year*each year*

* FDA/CFSAN. 2004. Produce safety from production to consumption:2004 action plan to minimize foodborne illness associated with fresh produce consumption. http://www.cfsan.fda.gov/~dms/prodpla2.html

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Foodborne Illness Statistics

Food service: Food service: 61%61% Homes: Homes: 32%32% Plants: Plants: 7% 7%

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Foodborne Illness: Symptoms Upset stomachUpset stomach Fever Fever HeadacheHeadache NauseaNausea VomitingVomiting DiarrheaDiarrhea Dehydration (sometimes severe) Dehydration (sometimes severe) MeningitisMeningitis ParalysisParalysis DeathDeath

Infective dose varies and is thought to be dependent upon the Infective dose varies and is thought to be dependent upon the susceptibility of the individual susceptibility of the individual As few as 10 to 100 pathogenic cells can make you sick!As few as 10 to 100 pathogenic cells can make you sick!

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Individuals More Susceptible to Foodborne Illness

The very young – The very young – infants and pre-school infants and pre-school age childrenage children

Older adultsOlder adults Pregnant womenPregnant women People taking certain People taking certain

medicines e.g. medicines e.g. antibiotics and antibiotics and immunosuppressants immunosuppressants

Those with weakened Those with weakened immune systems immune systems

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Relative Susceptibility to Listeriosis*

Condition Relative susceptibility

Transplant 2584

Cancer-Blood 1364

AIDS 865

Dialysis 476

Cancer-Pulmonary 229

Cancer-GI/Liver 211

Cancer-Bladder/Prostate 112

Diabetes-non-insulin dep. 25

Diabetes-insulin dep. 30

Alcoholism 19

Over 65 years old 7.5

<65, no other condition 1

* Goulet & Marchetti, 1996

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Foodborne Illness Statistics

Microbial: 94% of foodborne illnessesMicrobial: 94% of foodborne illnesses Chemical: 4%Chemical: 4% Physical:Physical: 2%2%

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Microbial Hazards

Microbial Hazards:Microbial Hazards: BacteriaBacteria VirusesViruses Fungi (yeasts, molds)Fungi (yeasts, molds) ParasitesParasites

BacteriaBacteria are the leading cause of are the leading cause of foodborne illnessfoodborne illness

E. Coli Gram Stain,CDC

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FAT TOM*

What Conditions Do Foodborne Microorganisms Need To Grow?

Food

Acidity

Temperature

Time

Oxygen

Moisture

* NRAEF ServSafe Coursebook – Fourth Edition

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FAT TOM

FoodFood Foodborne microorganisms need nutrients Foodborne microorganisms need nutrients

to grow. Specifically:to grow. Specifically: carbohydratescarbohydrates proteinsproteins

F

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FAT TOM

AcidityAcidity Foodborne microorganisms grow Foodborne microorganisms grow

best in food that has a pH range of 4.6 to 7.5 (food best in food that has a pH range of 4.6 to 7.5 (food with slightly acidic pH or neutral pH)with slightly acidic pH or neutral pH)

pH of most products falls into this rangepH of most products falls into this range

Vinegar = 2.0Baking Soda = 8.1

A

Acidic Neutral Alkaline

pH 4.6 pH 7.5 pH of most food is 4.6 to 7.5 Bacteria grow best in food with pH values 4.6 to 7.5

0 7 14

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FAT TOM

135ºF (57ºC)

41ºF (5ºC)

98.6ºF (37ºC) TemperatureDanger Zone(41 to 135ºF)

Ideal for bacterialgrowth

Temperature

– Foodborne microorganisms survive and grow well at temperatures between 41˚F and 135˚F*

* These temperatures based on current FDA Food Code/USDA Guidance. State regulations may differ.

T

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FAT TOM

TimeTime Foodborne microorganisms need Foodborne microorganisms need

sufficient time to growsufficient time to grow Bacterial cells divide every 20 minutesBacterial cells divide every 20 minutes Storing food in TDZ for 4 hours or more would Storing food in TDZ for 4 hours or more would

result in bacterial growth and multiplication to result in bacterial growth and multiplication to dangerous levelsdangerous levels

T

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Bacterial Multiplication

Cells divide twofold every 20 minutes

TimeT

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FAT TOM

OxygenOxygen Some foodborne microorganisms Some foodborne microorganisms

require different levels of oxygen or no oxygen at require different levels of oxygen or no oxygen at all to growall to grow

Aerobes: require oxygen to growAerobes: require oxygen to grow• e.g. e.g. SalmonellaSalmonella, , E.coliE.coli

Facultative anaerobes: are able to grow either Facultative anaerobes: are able to grow either with or without free oxygen with or without free oxygen

• e.g. e.g. Staphylococcus aureusStaphylococcus aureus Obligate anaerobes: can survive and grow Obligate anaerobes: can survive and grow

only when oxygen is absentonly when oxygen is absent• e.g. e.g. ClostridiumClostridium spp. spp.

O

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FAT TOM

MoistureMoisture Most foodborne Most foodborne

microorganisms microorganisms require moisture to require moisture to growgrow

The amount of The amount of moisture available in moisture available in food for this growth is food for this growth is called water called water activity (aw)activity (aw)

M

Water activity (aw) scale:

No growth Growth

aw minima for growth of microorganisms:

Staphylococcus aureus 0.86 Salmonella spp. 0.93 Clostridium botulinum 0.93 Clostridium perfringens 0.93 Bacillus cereus 0.95

0 10.85

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FAT TOM Several methods can be used to keep Several methods can be used to keep

microorganisms from growing: microorganisms from growing: Add lactic or citric acid to food to make it more Add lactic or citric acid to food to make it more

acidic*acidic* TemperatureTemperature

Refrigerate or freeze food properlyRefrigerate or freeze food properly Cook food properlyCook food properly

TimeTime Minimize time food spends Minimize time food spends

in the TDZ (41 to 135ºF)in the TDZ (41 to 135ºF) Use vacuum packaging to remove oxygen*Use vacuum packaging to remove oxygen* Add sugar, alcohol, or acid to lower food’s water Add sugar, alcohol, or acid to lower food’s water

activity*activity*

*Only food processors can use methods involving food acidification, modified atmosphere packaging, and moisture reduction

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Food Safety Management Systems

Food Safety Management Systems Grower Food

processor

Food service Consumer

GAPs, GHPs

HACCP, GMPs, SOPs, SSOPs

HACCP, Active Managerial Control, SOPs

—

Prevent

hazards

Reduce hazards to safe levels

Eliminate hazards

Prevent

hazards

Reduce hazards to safe levels

Eliminate hazards

Prevent

hazards

Reduce hazards to safe levels

Eliminate hazards

Prevent

hazards

Reduce hazards to safe levels

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Microbial Hazards

Microbial Hazards:Microbial Hazards: BacteriaBacteria VirusesViruses Fungi (yeasts, molds)Fungi (yeasts, molds) ParasitesParasites

BacteriaBacteria are the leading cause of are the leading cause of foodborne illnessfoodborne illness

E. Coli Gram Stain,CDC

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Some Pathogens Concern in Fresh Produce

BacteriaBacteria Salmonella Salmonella spp.spp. E. coli E. coli O157:H7O157:H7 Shigella Shigella spp.spp. Bacillus cereusBacillus cereus Clostridium botulinumClostridium botulinum Listeria Listeria

monocytogenes monocytogenes Vibrio choleraVibrio cholera

VirusesViruses Hepatitis AHepatitis A virus virus Norwalk/Norwalk-like Norwalk/Norwalk-like

virusvirus

ParasitesParasites Cyclospora Cyclospora spp.spp. Cryptosporidium Cryptosporidium

spp.spp. GiardiaGiardia

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Where Microbial Pathogens Live

Common in soils…Common in soils…Listeria Listeria monocytogenesmonocytogenes

Bacillus cereusBacillus cereusClostridium Clostridium botulinumbotulinum

Residents of human Residents of human and animal intestinal and animal intestinal tracts…tracts… Salmonella Salmonella speciesspecies E. coli E. coli O157:H7O157:H7 Shigella Shigella speciesspecies Viruses and Viruses and

parasitesparasites

National GAPs Program

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Sources of Pathogenic Microorganisms on Fresh Produce

human and animal feceshuman and animal feces contaminated watercontaminated water unsanitary farm environmentunsanitary farm environment unsanitary facilitiesunsanitary facilities improperly treated animal manure or biosolid improperly treated animal manure or biosolid

wasteswastes poor worker hygiene and sanitation practices poor worker hygiene and sanitation practices

during production, harvesting, sorting, during production, harvesting, sorting, packing, and transport packing, and transport

cross-contamination during transport of fresh cross-contamination during transport of fresh produce from farm to market produce from farm to market

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An ounce of prevention is

worth a pound of cure

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Good Agricultural Practices (GAPs)

GAPs are the basic environmental and operational GAPs are the basic environmental and operational conditions that are necessary for the production of conditions that are necessary for the production of safe, wholesome fruits and vegetables*safe, wholesome fruits and vegetables*

GAPs can enhance food safety and help prevent and GAPs can enhance food safety and help prevent and reduce the risk of foodborne illnessreduce the risk of foodborne illness

* Rangarajan, A., E.A. Bihn, R.B. Gravani, D.L. Scott, and M.P. Pritts. 2000. Food Safety Begins on the Farm: A Grower’s Guide. Cornell Good Agricultural Practices Program. Ithaca, NY.

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Strategies for Controlling Potential Microbial Food Safety Hazards on Your Farm You should control hazards during:You should control hazards during:

productionproduction harvestingharvesting postharvest handlingpostharvest handling

Farm food safety planFarm food safety plan

GoalGoal: Prevent contamination: Prevent contamination

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Prerequisite Food Safety Programs

Personal hygiene programPersonal hygiene program Employee food safety training programEmployee food safety training program

teach workers about food safety and their role in preventing teach workers about food safety and their role in preventing microbial contamination of fresh fruits and vegetablesmicrobial contamination of fresh fruits and vegetables

results = safer produce!results = safer produce! Provide well maintained restroom to employees and customersProvide well maintained restroom to employees and customers

handwashing stations must be equipped handwashing stations must be equipped sign should reflect all languages used on the farmsign should reflect all languages used on the farm

Record keepingRecord keeping document what your did for food safetydocument what your did for food safety Keep good records - important for tracebackKeep good records - important for traceback

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Review

Be aware of the sources of pathogenic Be aware of the sources of pathogenic microorganisms on fresh produce microorganisms on fresh produce

Understand food safety principlesUnderstand food safety principles PREVENT CONTAMINATION!PREVENT CONTAMINATION! Good Agricultural Practices (GAPs)Good Agricultural Practices (GAPs)

GAPs can enhance food safety and help GAPs can enhance food safety and help prevent and reduce the risk of foodborne prevent and reduce the risk of foodborne illnessillness

Farm Food Safety Plan

Develop a written farm food safety planDevelop a written farm food safety plan Implement farm food safety planImplement farm food safety plan Farm food safety plan in effectFarm food safety plan in effect

currentcurrent records on filerecords on file

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The End