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Current and Emerging Organisms in Raw Milk that Affect Public Health - Dr. Purnedu Vasavada, University of Wisconsin-River Falls, from NIAA's One Health: Implications for Animal Agriculture, March 15 - 17, 2010, Kansas City, MO, USA.
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© Dr. P.C. Vasavada.2010 All Rights Reserved.
Current and Emerging Organisms in Raw Milk that Affect Public Health
Dr. Purnendu C. Vasavada Animal and Food Science Department University of Wisconsin - River Falls
River Falls, WI 54022
Presented at 2010 NIAA Annual Meeting Kansas City, MO. March 15-17, 2010
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© Dr. P.C. Vasavada.2010 All Rights Reserved.
Main Objective To review current and emerging pathogens in raw
milk, including the “less recognized” and “presumptive” pathogens in the context of safety and public health risk associated with consumption of raw milk and in milk products manufactured from unpasteurized milk
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Milk Mustaches…
Raw Milk: = Alfred E. Newman
What, Me Worry?
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Introduction Microorganisms in milk Sources of microorganisms Pathogens in Milk – Historical aspects Current and Emerging Pathogens Less recognized and presumptive pathogens Summary
Outline
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UW River Falls
UW River Falls
30 th UW River Falls Food Microbiology Symposium and Rapid Methods in Food Microbiology Workshop River Falls, WI.USA , October 17-20, 2010
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Significance of Microorganisms in Milk Quality and shelf life Regulatory and vendor compliance Fermentation, starter cultures, flavor
organisms, adjunct flora, probiotic organisms Safety - Pathogens, toxins, biosecurity
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Bacteria Yeast and molds Viruses/Bacteriophages Rickettsiae
Microorganisms in milk
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Bacillus*
Corynebacterium Clostridium
Enterococcus
Lactobacillus Listeria*
Microbacterium Micrococcus Pediococcus
Weisella
Important spoilage microorganisms- Bacteria
Achromobacter* Acinetobacter*
Alcaligenes*
Enterobacter Escherichia
Flavobacterium
Moraxella* Proteus
Schewanella Zymomonas
Psychrotrophic
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Yeasts Candida
Cryptococcus Debaromyces Rhodotorula
Torulopsis Yarrowia
Important spoilage microorganisms -Yeast and Molds
Molds Alternaria
Aspergillus Aureobasidium Botrytis
Cladosporium Geotrichum
Mucor Penicillium Rhizopus
Thamnidium
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Milk from the healthy animal is usually sterile Contamination may occur from
Cow (Mastitis, Systemic disease (Bovine Tuberculosis) Skin microflora Environmental contamination (air, soil,dus), water,
manure, bedding material (sawdust), silage Equipment (milking equipment, pipe-line, utensils, drains,
transportation trucks Vector ( insects , flies) Humans ( personnel: milkers and milk handlers
Sources of microorganism in Raw Milk
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Raw milk recognized since early 1900s as a significant source of diseases
Pasteurization introduced in 1906, PMO developed in 1924 Milkborne outbreak constituted 25% of all disease outbreaks
due to contaminated food and water, today, less than 1% of all outbreaks attributed to contaminated milk and milk products.
Raw milk sales controlled or banned in over 40 states. 87% of raw milk outbreaks during 1973-1992 in states that
permit intrastate sale Position statements and scientific consensus about public
health risk of raw milk
Raw Milk and Public Health Threat
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Public Health, Regulatory and Educational Organizations’ Position on Raw Milk Issue American Veterinary Medical Association (AVMA) Association of Food & Drug Officials (AFDO) Health Canada National Association of State Departments of Agriculture (NASDA) National Association of State Public Health Veterinarians (NASPHV) National Conference on Interstate Milk Shipments (NCIMS) program State regulatory agencies University cooperative extension programs
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Raw milk demand growing Political pressure on relaxing/overturning milk
pasteurization regulations/allowing sale of raw milk
Less then 0.5% of U.S. milk is consumed unpasteurized.
Yet, raw milk and cheese result in approximately twice the outbreaks as conventional products
Raw Milk and Public Health Threat
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Growing Demand for Raw Milk and activism
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Mar 10, 2010 EAU CLAIRE, Wis. (AP) -- Hundreds of people packed a legislative hearing in Eau Claire Wednesday on legalizing the sale of unpasteurized milk. The proposed legislation would allow consumers to buy raw milk directly from a farm and give dairy farmers immunity from liability if someone got sick drinking the unpasteurized product.
Hearing Held About Legalizing Raw Milk
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Milkborne disease outbreaks by Food category, United States, 1973-2005
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Pathogens identified in unpasteurized dairy Products associated illness outbreaks, U.S., 1990-2006
• Source: SCPI Outbreak Alert! Database, 2008.
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Bellingham company recalls raw milk due to E. coli fears Posted on February 24, 2010 by Drew Falkenstein
a Bellingham, Washington company called Jackie's Jersey Milk recalled raw milk product due to possible contamination by E. coli O157:H7. The contamination was detected during routine sampling and testing of the company's products by the Washington State Department of Agriculture.
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Tuesday, March 16, 2010 • WALWORTH COUNTY, WI
State orders Elkhorn farm to stop raw milk sales through cow-share program ELKHORN — State agriculture officials have ordered an Elkhorn farm to stop selling raw milk through a cow-share program after more than two dozen people fell ill.
The order against Zinniker Farm Inc., says 35 people from Walworth, Waukesha and Racine counties have been diagnosed with campylobacter jejuni since Aug. 13. That’s a bacterial infection that causes diarrhea, cramping and vomiting.
All the victims said they had consumed raw milk. Thirty of them said they got it from the Zinniker farm. Tests matched campylobacter jejuni found in 29 victims’ feces to campylobacter jejuni found in cow feces on the farm.
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E. Coli in raw milk sends kids to the hospital December 13, 2005 By Brian Barker and KATU Web Staff VANCOUVER, Wash. - If you or your children have been drinking unpasteurized milk or been experiencing diarrhea, you might want to get checked out by a doctor.
The Clark County Health Department says they have confirmed six cases of E. coli have in children between the ages of 5 and 19.
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FDA Warns Consumers to Avoid Drinking Raw Milk
E coli outbreak in Washington blamed on raw milk Raw milk distributors targeted by regulators
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E. coli 0157:H7 infection associated with Unpasteurized Goat’s Milk
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UK: Threat of E-coli contamination spreads
23 Dec 2005 Source: just-food.com
Fears that certain brands of camembert may be infected with the dangerous strain of E-coli, 026, have spread to include other raw milk products imported from France, the Food Standards Agency (FSA) announced yesterday (23 December).
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Pathogens in Raw Milk - Historical aspects
M. tuberculosis C. diptheriae C. burnetii Staph. aureus Salmonella Streptococci Brucellae
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Pasteurization statutes - 1906/ PMO adoption “TB Free” and “Brucella Free” status of dairy herds “Certified” milk movement Refrigeration of milk On-farm hygiene and milk quality programs
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Current and Emerging Pathogens Emerging Pathogens are infectious agents whose incidence in humans has increased dramatically within the past two decades, or one that has the probability of increasing in future
CDC (1994)
Salmonella spp. E. coli 0157:H7 Listreia monocytogenes* Yersinia enterocolitica* Staphylococcus aureus Clostridium spp. Bacillus cereus* Campylobacter jejuni * Pyschrotrophic
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Pathogens in raw milk Several well designed studies to assess incidence of
pathogens in raw milk Steel et al. 1997 Ontario Bulk Tank Raw Milk Jayarao and Henning 2001. Bulk tank milk in SD and
Western Mn Waak et al. 2002. Listeria monocytogenes in raw milk in
Swedish dairy Karns et al 2005. Salmonella enterica in bulk tank milk by
PCR
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Pathogens in Bulk Tank Milk
Oliver et al (2009
Pathogen % Campylobacter 2 – 9.2% E. coli O157:H7 0 - 0.75% Listeria monocytogenes 2.8 - 7.0%
Salmonella spp 0 – 11% Shiga-toxin E. coli 2.4 - 3.96% Yersinia enterocolitica 1.2 – 6.1%
Oliver et al (2009)
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Pathogens in raw milk*
Pathogen % positive
Campylobacter jejuni 0.4 – 12.3 % E. coli 0157:H7 0.8 – 3.8% Salmonella spp. 0.2 – 8.9% L. Monocytogenes** 1.0 – 12.6 % Y. enterocolitica 11.3 - 89%
• Compiled from Several International studies, Oliver et al. 2005.
** Incidence of L.M. in raw milk varies from 0 %- 45.3 %
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Yersinia enterocolitica in Raw Milk
Larkin et al. 1991
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Campylobacter jejuni in Raw Milk
Larkin et al. 1991
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Changing Paradigm – Microorganisms: The Good Bad and Ugly
New category: Less recognized/ presumptive /opportunistic pathogens
Beneficial Organisms Spoilage Organisms Recognized and emerging pathogens
Less Recognized and Suspected Pathogens
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Less Recognized and Suspected Foodborne Pathogens
Enterobacteriaceae Helicobacter and Arcobacter Spore forming organisms Lactic acid bacteria Coryniform and Mycobacteria Zoonotic organisms
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Less Recognized and Suspected Foodborne Pathogens Enterobacteriaceae
Citrobacter spp., 5 outbreaks 3 attributed to milk
Klebsiella. Isolated from milk, milk products, water, vegetation
Spore forming organisms Bacillus cereus, B. brevis, B.licheniformis Clostridium perfringens
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Enterobacter sakazakii Linked to deaths of premature infants in neonatal
intensive care units Reconstituted infant formulae Several recalls of infant formulae Environmental contamination
C. sak
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E. Sakazakii Necrotizing enterocolitis, sepsis, meningitis in neonatal infants Powdered milk-based infant formulae
recognized as a vehicle for infection Outcome poor (fatality rate 40 - 80%) Wide spread in environment Variable heat resistance Biofilm production
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E. sakazakii - Heat Resistance
D = 30.5 sec
D = 591.9 sec
Thermal Death Time Curves for 2 E. Sakazakii Heated at 58°C
E. sakazakii- Biofilm Formation Stainless Steel: Adherent Micro-Colonies
Hoescht Stain of ES after attachment (1:10 TSB – 4 h, RT), rinsing and Incubation (TSB – 24 h and 48 h at 37oC)
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Less Recognized and Suspected Foodborne Pathogens
Zoonotic pathogens Mycobacterium paratuberculosis Brucellosis Q fever Leptospirosis
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Mycobacterium paratuberculosis (MAP)
Johne’s and Crohn’s disease Detection and isolation of M. paratb. Heat inactivation of MAP
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Other Mycobacterium spp. M. bovis M. scrofulaceum
Associated with infected lymph nodes in children
isolated from raw milk M. gordonae
“tap water bacillus” Isolated from raw milk and water
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© Dr. P.C. Vasavada.2010 All Rights Reserved.
Brucellosis Zoonoses affecting farmers, Vets Undulant fever, Malta fever
B.abortus, B. melitensis, B.suis Brucellosis outbreak associated with soft
cheese from unpasteurized sheep and goat’s milk and travel to endemic areas
Trends in Raw milk/Cheese consumption Disease making a come back?
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Less Recognized and Suspected Foodborne Pathogens:”LAB”
Streptococci S.pyogenes, S. agalactiae S. zooepidemicus Enterococci E. durans, E, feacium, E. fecalis Lactobacillus, Lactococcus,
Leuconostock & Pediococci All isolated from human infection
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Less Recognized and Suspected Foodborne Pathogens Streptobacillus moniliformis Pleomorphic Gram negative rods Acute illness associated with rat- bite fever 1926 Haverhill fever traced to raw milk
consumption Coryniform bacteria C. diptheriae, C. bovis, C. ulcerans
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Less Recognized and Suspected Foodborne Pathogens Protozaon parasites Cryptosporidium Giardia Toxoplasma gondii – Raw Goat’s milk
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Coxiella burnetii
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Q Fever in The Netherlands December 16, 2009 An outbreak of Q fever 2,293 human cases have been confirmed
in 2009, including 6 deaths Part of the ongoing outbreak of Q fever in
the Netherlands since 2007 190 cases (2007)1,000 cases in 2008.
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Coxiella burnetii a highly infectious agent resistant to heat, drying, and many
common disinfectants, allowing it to survive for a long time in the environment.
can become airborne and inhaled by humans.
could be developed for use in biological warfare and is considered a potential terrorist threat.
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Q Fever - Recommendation- Eat only milk and dairy products that have
been pasteurized. Do not drink raw milk or eat raw milk
products.
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Summary Raw milk is a recognized source of pathogen Inadequate Some organisms pose special
challenge due to their slow growth, low occurrence or special characteristics
Detection challenges and approaches Education, awareness and implementation of
preventative strategies (HACCP)
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Emphasis on Dairy Products Quality and Safety
Quality Control Quality Assurance Quality Systems TQM HACCP On-Farm HACCP ? Hygiene
GMPs
HACCP
TQM
Microbes play a significant role in food quality and safety
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Detection Challenge Many suspected pathogens are :
Slow growing fastidious organisms VNC Similar to other contaminating flora Do not grow readily on microbial media ….and hence the need for novel approaches and methods
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Detection Challenge: MAP, Parasites and viruses On-farm “quick tests” in most cases have
not been tested or approved for use in milk Assays typically do not have the sensitivity or specificity to detect/indentify pathogens such as E. coli O157:H7 Multiplex detection not possible Molecular methods?
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PCRs, Biosensors and Microarrays: MAP, Parasites and viruses Rapid Progress made in detection
and characterization methods and approaches Symposia, workshops worldwide for research dissemination and training
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UW River Falls Food Microbiology Symposium
30 th UW River Falls Food Microbiology Symposium and Rapid Methods in Food Microbiology Workshop
River Falls, WI.USA October 17-20,2010
You are invited!!!
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© Dr. P.C. Vasavada.2010 All Rights Reserved.
Conclusion Raw milk and unpasterurized milk product
consumption continues to cause illness and outbreaks
Inadequate regulations restricting raw milk and unpasterurized milk product
Unpasteurized product outbreaks are more common and cause more severe illness than pasteurized product outbreak
Educate consumers, public health partners and legislators about health risks of consuming unpasteurized products
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Raw Milk Safety : Control of Pathogens
“First priority in producing dairy foods: produce safe foods.” “To produce safe dairy products, it is vital to understand the
causes of foodborne illness and the peculiarities of the organisms involved”
Elmer H. Marth, Emeritus Professor , UW- Madison
‘It is very difficult to get a person to understand something when his/her salary depends on not understanding it.’
Upton Sinclair from The Jungle
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Acknowledgement
Any Questions ??? Thank You !!
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See you in Wisconsin !!