Dr. Purnedu Vasavada - Current and Emerging Organisms in Raw Milk that Affect Public Health

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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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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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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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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 !!

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Dr. Purnedu Vasavada - Current and Emerging Organisms in Raw Milk that Affect Public Health