Colorado State University Extension
SafeFood Rapid Response Network
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IN THE NEWS
Edited by: Stephanie Wallner, M.S., Mary Schroeder, M.S., R.D, Pat Kendall, Ph.D., R.D., Colorado State - Winter 2007
MICROWAVES ZAP GERMS IN SPONGES
Dishcloths and sponges are known to breed harmful bacteria such as E. coli and Salmonella, potential sources of foodborne illness. Food safety experts have deliberated for years as to which is safer for kitchen clean-up. The debate may no longer matter, now that University of Florida researchers have discovered the germ-fighting abilities of a microwave oven.
Led by Gabriel Bitton, professor of environmental engineering, the research team found that placing wet sponges or scrubbers on high power for 2 minutes in a microwave oven can effectively zap microorganisms of all sorts. Although dishwashers are commonly used by consumers to clean sponges and scrubbers, the microwave is far superior according to these researchers.
The scientists soaked sponges and scrubbing pads in untreated wastewater containing fecal bacteria, viruses, protozoan parasites and bacterial spores (including Bacillus cereus spores which are quite resistant to radiation, heat and toxic chemicals, and are notoriously difficult to kill). They also used bacterial viruses as substitutes for disease-causing viruses, such as hepatitis A. They then used a microwave oven to zap the sponges and scrub pads for varying lengths of time, wringing them out and checking for microbes after each test.
The results were clear. Two minutes of microwaving on full power mode killed or inactivated more than 99 per cent of all the living pathogens in the sponges and pads. The Bacillus cereus spores required four minutes for total inactivation. Professor Bitton said the heat, rather than the microwave radiation, was the most likely cause of death for the pathogens. As the microwave works by exciting water molecules, it is important to put wet rather than dry sponges or scrub pads into the oven. Wetting the sponge first will also prevent the sponge from catching on fire.
It appears that the microwave is a very powerful and an inexpensive tool for sterilization. Because kitchen cloths/sponges are an ideal breeding ground for microbes, Bitton suggests that cooks should microwave these items every other day.
Source:
Park, D.K., Bitton, G., Melker, R. (2006). Microbial inactivation by microwave radiation in the home environment. Journal of Environmental Health, 69(5), 17-24.
ALOE VERA IMPROVES PRODUCE QUALITY AND SAFETY
Aloe vera is a tropical and subtropical plant that has been used for centuries for its medicinal and therapeutic properties. Researchers in Spain have now developed a special aloe vera gel for use as an edible coating to prolong the quality and safety of fresh produce. With growing consumer concern over the use of chemicals as a means of food preservation, edible coatings such as this provide a safe, natural and environmentally-friendly alternative to conventional synthetic preservatives that are currently applied to produce after harvesting.
For this study, researchers chose table grapes, which like many fruits undergo changes during storage that induce and accelerate the ripening process, thus reducing their overall shelf life and making them susceptible to fungal decay and invasion by foodborne pathogens. A group of Crimson Seedless grapes was dipped in the aloe vera gel and stored for five weeks under low temperatures. A second untreated group was similarly stored, with changes in quality between the two groups determined over time. The untreated grapes showed signs of deterioration within about seven days, whereas the gel-coated grapes remained well-preserved for up to 35 days under the same experimental conditions. The gel-treated grapes maintained firmness, experienced less weight loss and less color change (factors associated with increased ripeness and spoilage) than the untreated grapes. Additionally, sensory comparison of both untreated and gel-treated grapes found that the gel-treated grapes were generally superior in taste.
High in antioxidants, the gel appears to act as a natural barrier to moisture and oxygen, aspects which often speed food deterioration. Additionally, the gel appears to contain various antibiotic and antifungal compounds that can potentially delay or inhibit microorganisms that can cause foodborne illness and food spoilage. The interest in beneficial properties of Aloe vera and other natural compounds by the food industry may soon lead to new functional food ingredients which improve food safety and quality in a variety of foods and beverages.
Source:
Serrano, M. Valverde, J.M. Guillen, F., Castillo, S., Martinez-Romero, D. Valero, D. (2006). Use of Aloe vera gel coating preserves the functional properties of table grapes. J. Agric. Food Chem, 54, 3882-3886.
ONLINE MASTERS (PROMS) DEGREE PROGRAM
MICHIGAN STATE UNIVERSITY
Anew distance learning opportunity is now available through Michigan State University's online Professional Master of Science (ProMS) in Food Safety degree. The program was created in response to a marketing research study that revealed an undeniable need on the part of the food industry, government and public health for their employees to be specifically educated in the many aspects of safeguarding our food supply. The program results in a 30-graduate credit master of science degree. The ProMS in Food Safety Program is offered through the College of Veterinary Medicine at MSU as a "Plan B" non-thesis program intended for mid-career/mid-management working professionals. For more information, go to: http://www.foodsafe.msu.edu/education.html.
