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

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

© Dr. P.C. Vasavada.2010 All Rights Reserved.

1

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


2

Milk Mustaches… What, Me Worry?

Raw Milk: =
Alfred E. Newman


3

Outline
  Introduction
  Microorganisms in milk
  Sources of microorganisms
  Pathogens in Milk – Historical aspects
  Current and Emerging Pathogens
  Less recognized and presumptive pathogens
  Summary


4

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


6

Microorganisms in milk
  Bacteria
  Yeast and molds
  Viruses/Bacteriophages
  Rickettsiae


7

Important spoilage microorganisms-
Bacteria
  Bacillus*   Achromobacter*
  Corynebacterium   Acinetobacter*
  Clostridium   Alcaligenes*
  Enterococcus   Enterobacter
  Lactobacillus   Escherichia
  Listeria*
  Flavobacterium
  Microbacterium
  Moraxella*
  Micrococcus
  Proteus
  Pediococcus
  Weisella
  Schewanella

 Psychrotrophic
  Zymomonas

8

Important spoilage microorganisms -
Yeast and Molds
Yeasts Molds
  Candida   Alternaria
  Cryptococcus   Aspergillus
  Debaromyces   Aureobasidium
  Rhodotorula   Botrytis
  Torulopsis   Cladosporium
  Yarrowia   Geotrichum
  Mucor
  Penicillium
  Rhizopus
  Thamnidium

9

Sources of microorganism in Raw Milk
  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

10

Raw Milk and Public Health Threat
  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

11

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

12

Raw Milk and Public Health Threat
  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


13

Growing Demand for Raw Milk
and activism


14

Hearing Held About Legalizing Raw Milk

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.

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16

Milkborne disease outbreaks by Food
category, United States, 1973-2005


17

Pathogens identified in unpasteurized dairy
Products associated illness outbreaks, U.S.,
1990-2006

• Source: SCPI Outbreak Alert! Database, 2008.


18

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.


19


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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.

21


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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.


26

FDA Warns Consumers to Avoid
Drinking Raw Milk
E coli outbreak in Washington
blamed on raw milk
Raw milk distributors targeted
by regulators


27


28

E. coli 0157:H7 infection associated with
Unpasteurized Goat’s Milk


29

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).


30


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Pathogens in Raw Milk -
Historical aspects
 M. tuberculosis
 C. diptheriae
 C. burnetii
 Staph. aureus
 Salmonella
 Streptococci
 Brucellae

32

  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


33

Current and Emerging Pathogens
  Salmonella spp. Emerging Pathogens are infectious
  E. coli 0157:H7 agents whose incidence in humans has
increased dramatically within the past two
  Listreia monocytogenes*
decades, or one that has the probability
  Yersinia enterocolitica* of increasing in future
  Staphylococcus aureus CDC (1994)

  Clostridium spp.
  Bacillus cereus*
* Pyschrotrophic
  Campylobacter jejuni

34

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

35

Pathogens in Bulk Tank Milk
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 Oliver et-al (2009
2.4 3.96%
Yersinia enterocolitica 1.2 – 6.1%
Oliver et al (2009)


36

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 %


37

Yersinia enterocolitica in Raw Milk

Larkin et al. 1991

38

Campylobacter jejuni in Raw Milk

Larkin et al. 1991

39

Less Recognized and Suspected Pathogens
Changing Paradigm –
Microorganisms: The Good Bad and Ugly
  Beneficial Organisms
  Spoilage Organisms
  Recognized and emerging pathogens
New category:
Less recognized/ presumptive /opportunistic
pathogens

40

Less Recognized and Suspected
Foodborne Pathogens
  Enterobacteriaceae
  Helicobacter and Arcobacter
  Spore forming organisms
  Lactic acid bacteria
  Coryniform and Mycobacteria
  Zoonotic organisms


41

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


42

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

43

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


44

E. sakazakii - Heat Resistance
Thermal Death Time Curves for
2 E. Sakazakii Heated at 58°C

D = 591.9 sec

D = 30.5 sec

E. sakazakii- Biofilm Formation
Stainless Steel: Adherent Micro-Colonies
Hoescht Stain of ES after attachment (1:10 TSB – 4 h, RT),
rinsing and Incubation (TSBReserved. and 48 h at 37oC)
© Dr. P.C. Vasavada.2010 All Rights – 24 h

45

Foodborne Pathogens
Zoonotic pathogens
  Mycobacterium paratuberculosis
  Brucellosis
  Q fever
  Leptospirosis


46

Mycobacterium paratuberculosis (MAP)
  Johne’s and Crohn’s disease
  Detection and isolation of M. paratb.
  Heat inactivation of MAP


47

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

48

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?

49

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

50

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
 

51

Foodborne Pathogens
  Protozaon parasites
  Cryptosporidium
  Giardia
  Toxoplasma gondii – Raw Goat’s milk


52

Coxiella burnetii


53

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.


54

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.

55

Q Fever - Recommendation-
  Eat only milk and dairy products that have
been pasteurized.
  Do not drink raw milk or eat raw milk
products.


56

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)


57

Emphasis on Dairy Products
Quality and Safety
  Quality Control
  Quality Assurance
TQM
  Quality Systems
HACCP
  TQM
GMPs
  HACCP
Hygiene
  On-Farm HACCP ?
Microbes play a significant role in food quality and safety

58

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


59

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?


60

PCRs, Biosensors and Microarrays:
MAP, Parasites and viruses detection
Rapid Progress made in
and characterization methods and
approaches
Symposia, workshops worldwide for
research dissemination and training


61

UW River Falls
Food Microbiology Symposium

30 th UW River Falls You are invited!!!
Food Microbiology Symposium and Rapid
Methods in Food Microbiology Workshop
River Falls, WI.USA
October 17-20,2010

62

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

63

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
 

64


Acknowledgement

Thank You !! Any Questions ???

65

See you in Wisconsin !!


66

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

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