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Food Protection Trends
Abstracts - March 2006
Restaurant-associated Outbreak of Salmonella Serotype Heidelberg Linked to Improperly Handled Mushrooms, Wyoming, 2003
New York State Cottage Cheese Shelf-life Characteristics: A Sixteen-year Perspective
Food Drying Workshops Promote Safe Home
Drying Methods
Restaurant-associated Outbreak of Salmonella Serotype Heidelberg Linked to Improperly Handled Mushrooms, Wyoming, 2003
Kelly N. Weidenbach-1, Scott A. Seys-1, Joslyn D. Cassady-1,2, Dean L. Finkenbinder-3,
Neal Bloomenrader-3, Annette G. Heryford-1, Wanda A. Manley-1, James R. Walford-1,
and J. Eric Buxman-1
1-Infectious Disease Epidemiology Program, Wyoming Department of Health, 6101 North Yellowstone Road,
Suite 510, Cheyenne, WY 82002, USA
2-Epidemiology Program Office, Centers for Disease Control and Prevention,
Atlanta, GA, 30333, USA
3-Wyoming Department of Agriculture, Cheyenne, WY, 82002, USA
SUMMARY
In May–June 2003, the Wyoming Department of Health investigated a protracted outbreak of Salmonella
serotype Heidelberg associated with a restaurant in Park County, Wyoming. A total of 65 cases of salmonellosis
were identified, of which 39 were laboratory-confirmed. Three state agencies coordinated a multidisciplinary,
three-pronged outbreak investigation, which included epidemiologic techniques, a systems-based environmental
health investigation, and laboratory methods. The case-control study revealed that mushrooms (OR=20.6;
95% CI=6.43–66.32) and Swiss cheese (OR=8.2, 95%CI=2.49–27.10) were associated with gastroenteritis.
Mushrooms that had once been canned tested positive for S. Heidelberg. Pulsed-field gel electrophoresis
(PFGE) results demonstrated that all Salmonella isolates from case-patients and from the mushrooms were
indistinguishable. Approximately 90% of restaurant patrons who consumed mushrooms became ill.
Contamination of the canned mushrooms during commercial processing was unlikely. The environmental
assessment of food-handling practices revealed multiple opportunities for cross contamination of mushrooms
and other food items with raw meat and poultry products. Additionally, foodhandlers had bare hand contact
with these ready-to-eat food items. This outbreak investigation identified improperly handled mushrooms as
the most likely vehicle of Salmonella Heidelberg. The implementation of a rigorous, multidisciplinary investigation
was critical in identifying the vehicle of transmission, determining the food-handling practices that led to the
outbreak, and implementing control measures.
New York State Cottage Cheese Shelf-life Characteristics: A Sixteen-year Perspective
Steven C. Murphy, Nancy R. Carey, Barbara H. Hammond, and Kathryn J. Boor
Department of Food Science, Cornell University, 413 Stocking Hall, Ithaca, NY 14853, USA
SUMMARY
By multiple criteria, the quality of cottage cheese products
manufactured in New York State has improved measurably between
1988 and 2004. From 1999 to 2004, the average sell-by date on
cottage cheese products collected in New York State was 46.9 days
post-packaging, in contrast to an average 28.0 day sell-by date on
similar products from 1988 to 1992. At 28 days of storage at 6.1oC,
gram-negative bacteria were detected in 2.0% of cottage cheese
samples collected from 1999 to 2004 (n=179), as compared to 29.4%
of samples collected from 1988 to 1992 (n=80). While 5.0% of the
samples analyzed from 1999 to 2004 were determined to be
“unacceptable” by sensory analyses at 28 days post-processing, fully
35.0% of samples tested from 1988 to 1992 were “unacceptable” at
28 days. Factors contributing to the improvements measured in New
York State cottage cheese product characteristics, including adoption
of carbon dioxide addition to cottage cheese dressing prior to
blending, are discussed.
Food Drying Workshops Promote Safe Home
Drying Methods
Patricia A. DiPersio-1, John N. Sofos-2, and Patricia A. Kendall-1
1-Department of Food Science and Human Nutrition and Department of Animal Sciences,
2-Colorado State University, Fort Collins, CO 80523, USA
SUMMARY
Illnesses associated with dried foods have raised concerns about
the safety of home drying methods. Studies at Colorado State
University with apples, beef, carrots, parsley, peaches, potatoes and
tomatoes showed that traditional drying methods may allow survival
of Escherichia coli O157:H7, Salmonella and Listeria monocytogenes,
and that simple modifications enhanced pathogen inactivation during
dehydration. To encourage adoption of modified recommendations,
a booklet, Drying Foods, and workshop were developed and pilottested
with extension educators and volunteers (n = 75). Social
Cognitive Theory and the Health Belief Model guided development
of the materials and workshop. Surveys assessed food drying
knowledge, attitudes and behavior pre-, post-and 6 weeks following
the workshop. Sensory assessments of dried carrot and potato slices
prepared using modified treatments enhanced experiential learning.
Knowledge and attitude scores regarding safe food drying methods
significantly (P < 0.05) improved between the pre-workshop
evaluation and the follow-up evaluation. Participants also indicated
improvements in food drying practices at the 6-week follow up. Acidblanched
potato slices received higher (P < 0.05) scores for
appearance, flavor and overall acceptability, compared with untreated
slices. Carrot samples received similar scores for flavor and
acceptability regardless of treatment. Outcomes indicate improved
subject knowledge, attitude and behavior, which may reinforce
adoption of new food drying guidelines.
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