Raw milk

September 19, 2004

Since a recent link mentioned raw milk I thought I'd post a few current

abstracts on the subject plus a few on BLV.

J Dairy Sci. 2004 Sep;87(9):2822-2830.

Prevalence of Salmonellae, Listeria monocytogenes, and Fecal Coliforms in

Bulk Tank Milk on US Dairies.

Van Kessel JS, Karns JS, Gorski L, McCluskey BJ, Perdue ML.

USDA-ARS, Beltsville, MD 20705.

The objective of this study was to determine the prevalence of Salmonella,

Listeria monocytogenes, and fecal coliforms in bulk tank milk in the United

States. As part of the NAHMS Dairy 2002 survey, 861 bulk tank milk samples

were collected from farms in 21 states. Milk was directly plated on

selective agars for direct bacterial enumeration and was enriched in

selective broths to increase detection sensitivity. Somatic cell counts

(SCC) and standard plate counts (SPC) were also determined. Coliforms were

detected in 95% (818 of 860) of the samples, and the average SCC was 295,000

cells/mL. Twenty-two samples (2.6%) were culture-positive for Salmonella,

and 9 serotypes were identified: Montevideo (n = 7), Newport (n = 4),

Muenster (n = 2), Meleagridis (n = 2), Cerro (n = 2), 44:Z36 (Z38) (n = 2),

Dublin (n = 1), Anatum (n = 1), and 9, 12:nonmo-tile (n = 1). Listeria

monocytogenes was isolated from 56 (6.5%) samples, and serotyping of these

isolates yielded 5 serotypes (1/2a, 1/2b, 3b, 4b, and 4c). Of the L.

monocytogenes isolates, 93% were serotypes 1/2a, 1/2b, and 4b, the most

common human clinical isolates. Regional differences in L. monocytogenes and

Salmonella prevalence were observed, but more studies are needed to

determine the validity of these differences. There were no apparent

relationships between SCC or SPC and incidence of Salmonella or L.

monocytogenes. Although the prevalence of L. monocytogenes and Salmonella

was low, these pathogens represent a potential risk to consumers of raw milk

and raw milk products.

PMID: 15375040 [PubMed - as supplied by publisher]

: Appl Environ Microbiol. 2004 Sep;70(9):5644-50. Related Articles, Links

Raw cow milk bacterial population shifts attributable to refrigeration.

Lafarge V, Ogier JC, Girard V, Maladen V, Leveau JY, Gruss A,

Delacroix-Buchet A.

Unite Composition et Hygiene des Produits Laitiers, Agence Francaise de

Securite Sanitaire des Aliments, 39-41 rue du 11 novembre 1918, 94700

Maisons Alfort, France. v.lafarge@...

We monitored the dynamic changes in the bacterial population in milk

associated with refrigeration. Direct analyses of DNA by using temporal

temperature gel electrophoresis (TTGE) and denaturing gradient gel

electrophoresis (DGGE) allowed us to make accurate species assignments for

bacteria with low-GC-content (low-GC%) (<55%) and medium- or high-GC% (>55%)

genomes, respectively. We examined raw milk samples before and after 24-h

conservation at 4 degrees C. Bacterial identification was facilitated by

comparison with an extensive bacterial reference database ( approximately

150 species) that we established with DNA fragments of pure bacterial

strains. Cloning and sequencing of fragments missing from the database were

used to achieve complete species identification. Considerable evolution of

bacterial populations occurred during conservation at 4 degrees C. TTGE and

DGGE are shown to be a powerful tool for identifying the main bacterial

species of the raw milk samples and for monitoring changes in bacterial

populations during conservation at 4 degrees C. The emergence of

psychrotrophic bacteria such as Listeria spp. or Aeromonas hydrophila is

demonstrated.

PMID: 15345453 [PubMed - in process]

Annu Rev Microbiol. 2004 Jun 2 [Epub ahead of print] Related Articles, Links

e's Disease, Inflammatory Bowel Disease, and Mycobacterium

paratuberculosis.

Chacon O, Bermudez LE, Barletta RG.

Department of Veterinary and Biomedical Sciences, University of Nebraska,

Lincoln, Lincoln, NE 68588; Seccion de Bacteriologia Corporacion para

Investigaciones Biologicas (CIB), Carrera, Medellin, Colombia

ochacon@..., Department of Biomedical Sciences, College of

Veterinary Medicine, Oregon State University, Corvallis, OR 97331

luiz.bermudez@..., Department of Veterinary and Biomedical

Sciences, University of Nebraska, Lincoln, Lincoln, NE 68588-0905

rbarletta@...

e's disease is a chronic diarrhea affecting all ruminants. Mycobacterium

avium subsp. paratuberculosis (MAP), a slow-growing mycobacteria, is the

etiologic agent. There is also a concern that MAP might be a causative agent

of some cases of inflammatory bowel disease in human beings, especially

Crohn's disease. Food products including pasteurized bovine milk have been

suggested as potential sources of human infection. This review addresses

microbial factors that may contribute to its pathogenicity. In addition, the

experimental evidence defining MAP as the cause of e's disease and, the

issues and controversies surrounding its potential pathogenic role in human

beings are discussed. Expected online publication date for the Annual Review

of Microbiology Volume 58 is September 8, 2004. Please see

http://www.annualreviews.org/catalog/pub_dates.asp for revised estimates.

PMID: 15355186 [PubMed - as supplied by publisher]

Prev Vet Med. 2003 Dec 12;61(4):249-62. Related Articles, Links

Association between bovine-leukosis virus seroprevalence and herd-level

productivity on US dairy farms.

Ott SL, R, Wells SJ.

USDA, Centers for Epidemiology and Animal Health, 2150 Centre Avenue,

Building B, Mail Stop 2E5, Fort , CO 80526-8117, USA.

stephen.l.ott@...

Bovine-leukosis virus (BLV; also termed 'bovine-leukemia virus') is a

retrovirus that primarily affects lymphoid tissue of dairy and beef cattle.

Our objective was to investigate the association between BLV infection and

annual value of production (AVP) on dairy herds within the United States, as

part of the USDA National Animal Health Monitoring System's 1996 dairy

study. 1006 herds (in 20 states) with at least 30 dairy cows were

interviewed during 1996. The agar-gel immunodiffusion test was used to

detect serum antibodies to BLV. 10-40 cows from each herd were tested and

each tested cow was classified as negative or positive based on results of a

single test. A multivariable regression model was used with the 976 herds

with complete data for analysis. When compared to herds with no

test-positive cows, herds with test-positive cows produced 218 kg per cow

(i.e. 3%) less milk. The average reduction in AVP was $59 per cow for

test-positive herds relative to test-negative herds. For the dairy industry

as a whole, BLV seropositivity was associated with loss to producers of $285

million and $240 million for consumers. Most of this $525 million industry

loss was due to reduced milk production in test-positive herds.

PMID: 14623410 [PubMed - indexed for MEDLINE]

AIDS Res Hum Retroviruses. 2003 Dec;19(12):1105-13.

Humans have antibodies reactive with Bovine leukemia virus.

Buehring GC, Philpott SM, Choi KY.

School of Public Health, University of California, Berkeley, California

94720, USA. buehring@...

Bovine leukemia virus (BLV) is an oncogenic retrovirus that commonly infects

cattle and causes B cell leukosis in 1-5% of infected cattle. BLV-infected

cells are present in marketed beef and dairy products. In the decade after

the discovery of BLV in 1969, studies using agar gel immunodiffusion and

complement fixation assays failed to find antibodies to BLV in human sera.

This led to the prevailing opinion that exposure of humans to BLV and/or the

potential for infection are not significant and therefore the virus is not a

public health hazard. We reexamined this issue using more sensitive

immunological techniques available today. Using immunoblotting to test the

sera of 257 humans for antibodies of four isotypes (IgG1, IgM, IgA, and

IgG4) to the BLV capsid antigen (p24), we detected at least one antibody

isotype reactive with BLV in 74% of the human sera tested. The specificity

of the reactivity was strongly suggested by competition studies and by

ruling out cross-reacting antibodies to other chronic human viruses. Our

results suggest that antibodies reactive with the BLV capsid antigen may

serve as a biomarker for exposure to BLV and this exposure may be

widespread. The results do not necessarily mean that humans are actually

infected with BLV; the antibodies could be a response to heat-denatured BLV

antigens consumed in food. They do, however, suggest that further studies in

this area could be important.

PMID: 14709247 [PubMed - indexed for MEDLINE]

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September 20, 2004

Timely post Cheryl.

Another parent remarked to me yesterday that stool feme and cultures should

be a regular part of the protocol lab work, esp if irregular bowel

activity is present.

We have done at least 7 over the last few years, and three times have

discovered horrible bugs - Gardia, a parasite, Salmonella and only last week

E.Coli. Each time when regular bloodwork was done before we discovered these

infections, EOS were elevated.

It is worth doing these, especially if your child is not yet able to

articulate " tummy aches "

Ours is learning the concept ..holds his tummy and says " hard " now he says

" tummy ache " . The other day he patted his head and said " tummy ache " - so

now we can provide the correct language and a " Nurofen " (like Motrin) and he

feels better!