Val Hillers, Ph.D., R.D.,
Washington State University
Ryan Bell, M.D., (M.S. from WSU)
Theo Thomas, WSU/Yakima Co. Cooperative Extension
In 1997, over 90 cases of Salmonella Typhimurium DT 104 were reported in Yakima County, Washington.
Symptoms included diarrhea, fever, abdominal pain, bloody stool,vomiting.
Median age was 4 years old.
Majority of cases involved children of Hispanic heritage.
A CDC study implicated unpasteurized-milk queso fresco as the source of the Salmonella infections.
Centers for Disease Control and Prevention (CDC) emphasized the need for an intervention.
(line graph showing increase in cases of S. Typhimurium infection in Yakima County and Washington State, by six-month interval, 1990-97)
Decrease consumption/production of unpasteurized-milk queso fresco
Increase knowledge of hazards associated with raw milk
Maintain/Promote a nutritious food in the Hispanic diet
Maintain a traditional food custom
Developed intervention and materials; conducted the program evaluation
Technical assistance to enable unlicensed vendors of queso fresco to develop safe product, get licensed
Implemented the consumer intervention
Newsletters to dairy farmers re risks of raw milk leaving their farm
Publicity about risks of raw milk and assistance in distribution of materials
Recruited people to participate in the intervention
Removed raw milk cheese from commerce
Encouraged dairy farmers to guard against raw milk leaving the farm
Provided encouragement, technical assistance
Collection of preliminary data via survey
Design of a safer, pasteurized-milk queso fresco recipe
Design of a flyer to illustrate the recipe
Acquisition of funding
Design of a program to introduce the new recipe
~ 50% got queso fresco from family member, neighbor, vendor.
~ 50% did not know if queso fresco was made from raw milk.
~ 40% did not believe raw-milk queso fresco could cause illness (~25% unsure).
~ 60% had not heard of Salmonella.
Preliminary pasteurized-milk recipe was obtained from Julia Herrera, a Mexican-American woman from Yakima, WA*
WSU dairy scientists Lloyd Luedecke and Mike Costello modified the recipe to:
Maintain acceptable taste/texture
(*The idea of modifying a recipe obtained from the local community was borrowed from a presentation re chitterlings by EA Peterson, 1997.)
Developed by Ryan Bell, M.S. student in human nutrition
Topics covered by the flyer:
Heat treatment of unpasteurized milk
Sanitization of cheese-making implements
Step-by-step instructions in Spanish and English
Has graphical illustrations for low literacy audience
(graphic - picture of brochure, English and Spanish)
(graphic - page from brochure, illustrating steps in safe queso fresco recipe)
$5,000 gift obtained from the Washington State Dairy Products Commission for Yakima County intervention.
Used to purchase Abuela Educator incentive package
Later, received $22,500 from USDA (EFSF-04800) to expand intervention to other counties in WA.
Abuela project received several awards, which included $6000 in award money. We used these funds to continue the intervention.
Older Hispanic "grandmothers"
hold positions of authority
carry on traditions
(We borrowed this idea from Colorado State University who trained Abuelas as nutrition educators.)
Original group - 15 people from Yakima County
Later, Abuelas were trained in 6 other counties
Training consisted of
How to make queso fresco with pasteurized milk
Hazards of raw milk
How to sanitize equipment
Each Abuela agreed to teach 15 others.
5-quart mixing bowl
8-cup mixing bowl
6-quart stock pot
8-cup mixing bowl
(photograph of training session in a kitchen)
Data was gathered from Abuela educators and participants in workshops.
Pre-test was administered just before the workshops.
Post-test was given at conclusion of the workshops.
Six-month follow-up interview was conducted via telephone by bilingual interviewers.
Yes, about 70% (n=177)
Maybe, more than 20% (n=44)
Yes, more than 80% (n=153)
Not sure (n=21)
Not sure (n=3)
Fresh unpasteurized, n=26
High-temperature/pasteurized milk, n=26
Not sure, n=6
Fresh unpasteurized, n=0
High-temperature/pasteurized milk, n=47
Making queso fresco at home is a strongly held custom within the Mexican-American community.
Many people were aware of the risks of raw milk. However, they continued to make raw-milk queso fresco to preserve their cultural heritage.
Behavior change was prompted by availability of a safer recipe that yielded an acceptable product.
Mexican-Americans were very receptive to using the recipe for pasteurized milk queso fresco because:
The pasteurized milk cheese was safer to eat.
The recipe was easier to make than the traditional recipe.
The recipe produced a good tasting cheese.
We modified a recipe developed by a respected women in the community, which encouraged acceptance of the recipe.
The incentives encouraged participation in the safe cheese workshops.
We surveyed people who did not participate in safe cheese workshops to see if the publicity had increased awareness of risks of raw milk queso fresco.
Don't Know, n=22
Don't Know, n=45
(line graph shows that post-intervention - 1997 - the number of S. Typhimurium cases in Yakima County and Washington State declined.)
Incidence of Salmonella infections dropped rapidly during the intervention.
Avoiding illness of the children appears to have been a prime motivator.
The cultural tradition of home preparation of queso fresco was preserved.
Some of the unlicensed small vendors who were formerly selling raw-milk queso fresco are now licensed and sell pasteurized-milk queso fresco.
Many food safety educational campaigns focus on avoiding certain risky foods.
Encouraging people to abandon a food custom accelerates cultural decomposition and may be nutritionally deleterious.
If possible, interventions should encourage modification rather than elimination of traditional cultural foods.
Food safety interventions that use the expertise of nutrition educators, microbiologists, food scientists and community-based educators are most likely to be effective at reducing microbial risks, maintaining the traditional taste of foods, and preserving cultural food patterns.
Safe cheese workshops continue to be held in dairy farming areas of Washington.
In Yakima County, rates of Salmonella infections rise without continued intervention.
Video showing the process of making queso fresco was developed to use when hands-on training was not feasible.
More than 10,000 copies of the brochure have been distributed by WSU.
Brochure was reprinted by FDA for distribution at Health Fairs in major US cities.
Food safety educators in about 20 other countries have requested copies.
Home production of raw-milk fresh cheese is common in many countries.
Educators have revised the procedures as needed to produce the cheese made in their locality.
Available from Washington State University Bulletins Office (800-723-1763 or pubs.wsu.edu)
Fresh Cheese Made Safely
Video and brochure (VT108)
Queso Fresco Hecho Saludable
Video and brochure (VT108S)
Bell, Hillers and Thomas. The Abuela Project: Safe cheese workshops to reduce the incidence of Salmonella Typhimurium from consumption of raw-milk fresh cheese. Amer. J Public Health 1999; 89:1421-1424.
Bell, Hillers and Thomas. Hispanic grandmothers preserve cultural traditions and reduce foodborne illness by conducting safe cheese workshops. J Amer. Dietetics Assoc. 1999; 99:1114-1116.