In This Update:

2005 E. coli levels similar to last yearís low

CDC report shows Listeria incidence rises slightly

US Agricultural Groups Support Peru Trade Agreement

Determining the food irradiation beliefs of community nutrition educators: do beliefs influence educational outreach?

Electron beam and gamma irradiation effectively reduce Listeria monocytogenes populations on chopped romaine lettuce

Ridding Exotic Fruits of Bugs: irradiation Promises to Boost US Imports of Brazilian Papayas and Mangoes

Combination of hot-water surface pasteurization of whole fruit and low-dose gamma irradiation of fresh-cut cantaloupe

The Food Safety and Inspection Service (FSIS) E. coli sampling results show the prevalence of this pathogen in ground beef remains low. During the 2005 calendar year, just 0.173 percent of ground beef samples tested positive for E. coli O157:H7, which is similar to the 2004 level of 0.175 percent. In terms of ready-to-eat products, the number of samples testing positive for Listeria monocytogenes increased slightly during 2005 (up from 0.55% to 0.64%) while Salmonella levels decreased from 0.08 percent to just 0.06 percent. The full data are available on the FSIS Web site at http://www.fsis.usda.gov/Science/Microbiology/index.asp.

The FSIS sampling program started in 1994 to estimate the prevalence of certain pathogens in raw and ready-to-eat meat and poultry products. In 2005, FSIS collected nearly 11,000 samples and only found 19 to be positive for E. coli O157:H7. The declining trend in both the number of positive samples and human illness from this pathogen are due in part to the beef checkoff funded research into interventions that have been applied throughout the beef production chain.  

The Centers for Disease Control and Prevention released a report showing that while certain food-borne pathogens were declining, listeria incidents raised slightly, missing the government's goal of reducing listeria cases by 50 percent. Human occurrences of listeria were three cases per million people in 2005, compared with 2.7 cases per million in 2004.

The Agricultural Coalition for U.S.-Peru Trade sent a letter to every member of Congress urging them to support the Peru Trade Promotion Agreement (PTPA). The letter said, "The PTPA sets a new and higher standard for future trade pacts. More than two-thirds of current U.S. agricultural exports to Peru will immediately receive duty-free treatment upon entry into force of the agreement. The tariffs on remaining U.S. agricultural products will be reduced over time, with all tariffs eliminated within 17 years." At the present time, approximately 1.5% of U.S. agricultural exports to Peru have duty-free access.
 

The letter also stated, that without implementation of the PTPA, "U.S. agriculture will continue to be prejudiced by this non-reciprocal trade and will be forced to compete for business in Peru against countries that already have free trade agreements with the South American nation."
 

The coalition is comprised of 58 organizations including: American Farm Bureau Federation, American Meat Institute, American Soybean Association, National Association of Wheat Growers, National Cattlemen's Beef Association, National Chicken Council, National Corn Growers Association, National Milk Producers Federation, National Pork Producers Council, National Turkey Federation, and U.S. Apple Association.

OBJECTIVE: To develop an instrument to measure the food irradiation beliefs of community nutrition educators and to determine the influence of those beliefs on food irradiation educational outreach.

DESIGN: Survey development, cross-sectional telephone survey.

SETTING: Cooperative Extension Program.

PARTICIPANTS: All Family and Consumer Sciences (FCS) county extension agents serving in the most populated counties in Texas (n = 134, response rate = 99%). These participants may not be representative of all FCS extension agents.

VARIABLES MEASURED: Food irradiation beliefs and educational outreach as well as selected demographic variables.

ANALYSIS: To determine validity and reliability of the instrument, factor analysis and Cronbach's alpha were conducted, respectively. To determine if food irradiation beliefs influenced food irradiation educational outreach, logistic and multiple regression analyses were conducted, with significance set at P < .05. RESULTS: The instrument had adequate reliability; two belief scales were identified through factor analysis, referred to as Safety Beliefs and Understanding Beliefs. Additionally, regression analysis suggested that educators' beliefs about food irradiation influenced the amount of food irradiation education they provided.

CONCLUSIONS AND IMPLICATIONS: Results suggest that educators' beliefs about the safety and their understanding of food irradiation are predictors of the educational outreach they provide about it, indicating the potential value of professional development regarding food irradiation.

Thompson BM, Knight SL; Office of Curriculum, Baylor College of Medicine, Houston, Texas 77030-3498, USA. brittat@bcm.tmc.edu

ABSTRACT
Fresh, chopped romaine lettuce contaminated with a seven-strain cocktail of Listeria monocytogenes (in a solution containing approximately 108 organisms per ml) that had attained a level of contamination of between 7 and 8 log CFU/g was packaged in 15-g samples. The lettuce was irradiated with a Co60 source at 1.15 or 0.51 kGy and then stored at 4C. In addition, samples contaminated with isolated strains 16397, 0733, and 1992 were subjected to either electron beam irradiation at doses ranging from 0.3 to 1.2 kGy or gamma irradiation at 0.56 kGy without subsequent refrigerated storage. All postirradiation and control samples were diluted with Butterfieldís phosphate buffer and plated in duplicate on modified Oxford media. Samples that received electron beam or gamma irradiation without subsequent refrigerated storage were also plated in duplicate on modified Oxford media plates coated with two 7-ml layers of basal yeast extract agar. Electron beam irradiation yielded D10-values (the dose required to eliminate 90% of the microbial population) of 0.16, 0.17, and 0.19 kGy for strains 16397, 0733, and 1992, respectively. The corresponding log reductions obtained for these same three strains at 0.56 kGy of gamma irradiation were 2.91, 2.62, and 2.66 log, respectively. Gamma irradiation at 1.15 and 0.51 kGy with subsequent refrigerated storage (4C) reduced populations by 5 and 2 log, respectively, compared with controls. Neither the irradiated samples nor the control samples showed increases in population during the storage periods. Our results indicate that low-dose irradiation can effectively reduce or eliminate L. monocytogenes on chopped romaine lettuce, improving the safety of ready-to-eat salads.

Brazilian papayas are not first on most Americansí list of favorite fruits, but with increased migration of Latin Americans to the north this fruit is becoming more prominently displayed on grocer shelves.

Brazil is the worldís largest producer of papayas. The problem is that the fruit is a magnet for pests and, once tested to US. Department of Agriculture specifications, often risks high rates of spoilage while en route to US markets. George Karski, president of Concord. NH-based Securefoods, believes the answer to winning a place for Brazilian papayas in US fruit bowls, and improving its transport overseas, is to use irradiation treatment technology. His company, a subsidiary of gold mining and energy investment firm Brazilian Resources, is prepared to spend millions of dollars to build and operate irradiation equipment for Brazilís papaya export industry.

Brazilís papayas are traditionally treated for fruit flies with hot water dips. The treatments, while generally successful degrade the fruitís potential shelf life. Cheaper ocean transport is out of the picture for most Brazilian papaya exporters, who must use costly air transport to ship to U.S. markets. According to Karski, Brazilian papayas that do arrive in the United States in sellable condition still get shortchanged. The fruit is picked long before it ripens and tastes like cardboard, he said in a recent interview.

Irradiation treatment facilities placed close to growing areas will allow Brazilian papaya farmers to pick the fruit closer to its peak of taste, Karski said. Irradiation kills harmful bacteria and embedded insects, without changing the overall quality of the fruit. More importantly it slows ripening to allow Brazilís papaya exporters to take advantage of ocean transport. ìThe only loser from irradiation treatments will be the airline industry,î Karski said.

The average cost to fly a 10-pound carton of papayas from Brazil to the United States is about $9, compared to $1 per case for ocean transport. The fruit is generally sold to wholesalers who command a 10 to 5 percent commission from retailers. If ocean transport is used, the fruit could be sold at U.S. retail for about 90 cents per papaya compared to more than $1.50 with air transport, Karski explained.

Securefoods will use irradiation to treat a variety of Brazilian fruits, such as mangoes, for export to North America. Itís estimated that Brazil ships abroad more than $180 million in tropical fruits a year.

The Brazilian agricultural authorities support Securefoods irradiation treatment, but the program still requires bilateral approval from USDAís Animal and Plant Health Inspection Service, which Karski believes will happen soon. Once Securefoods gets its USDA approval, it will install four food irradiators in Bahia in Northeast Brazil. The regionís papaya production outstrips its domestic consumption. ìFruit is often discarded, or left rotting in the fields.î Karski said.

Securefoodsí first irradiator will be located in Eunapolis, Bahia, near the port of Ilheus. The second unit will be installed at Salvador, a large port and the capital of the State of Bahia. Fortaleza, Ceara, and Recife, Pernambuco, both of which are large papaya export areas, will be the sites for the two other units, Karski said. Irradiation technologies have been used for more than 40 years to sterilize medical, personal hygiene products and food packaging. In recent years, the meat industry has used irradiation to kill harmful bacteria, such as E. coli, salmonella, listeria, campylobacter and vibrio, in beef and poultry. Exposure to these bacteria contributes to 76 million food borne illness and about 5,000 deaths a year in the United States alone.

About 40 counties have approved irradiation treatments for about 40 food products. The International Consultative Group on Irradiation estimates that irradiation is used to treat about a billion pounds of food products and ingredients a year. In the United Stales, about 50 million pounds of spices are irradiated annually.

Numerous health organizations and government agencies, such as the American Medical Association, American Dietetic Association, US Center for Disease Control and Prevention, U.S. Food and Drug Administration, and World Health Organization, approve irradiation as a safe way to treat food products.

In 2002, USDA approved irradiation treatment for certain imported fruits and vegetables against 11 types of fruit flies and the mango seed weevil However, the technologyís use for this purpose has been minimal. USDA allows irradiation treatments for interstate movements of certain exotic fruits and sweet potatoes from Hawaii to the U.S. mainland. Interest in the technology has increased in recent years with fumigations and chemical treatments coming under increasing fire for their negative environmental and public health effects.

Methyl bromide is one of the most widely used fumigants for phytosanitary purposes in the United States and around the world. The fumigant, unlike others, penetrates produce completely without altering its appearance or taste. However, some scientists and environmental groups have pegged methyl bromide a major contributor to the earthís ozone depletion, especially when it is used for large-scale soil treatments.

In 1992, the 183 parties to the Montreal Protocol, including the United States, added methyl bromide to the list of ozone depleting substances, and production was frozen in 1995 to 1991 levels. When the parties met again in 1995, they agreed to completely phase out the gas among industrial countries by 2010. In 1997, the Montreal Protocol accelerated methyl bromideís phase-out for industrial countries to 2006. Starting in 1969, the use of the gas was reduced by 25 percent and by 50 percent in 2001. By January 2003, methyl bromides use was cut by 70 percent. Methyl bromide use in developing countries will end by 2015.

For quarantine purposes, the United States and other industrialized countries will allow approved agricultural products shippers to continue using methyl bromide, Even for those shippers allowed to continue using methyl bromide, the cost of the fumigants is expected to increase. Before 1999, methyl bromide treatments for cherry exports were generally $1.25 per pound. Today, methyl bromide fumigations exceed $5 per pound for this commodity.

Shippers and treatment providers are considering alternative treatments to methyl bromide. USDA, which has spent more than $146 million in research and outreach related to the development of treatment alternatives has become a proponent of irradiation technology.

ìTo me it provides a much safer environment than methyl bromide and other chemical treatments, said Inder ìPaulî Gadh, import specialist with USDAís APHIS. This technology has a lot of potential for use not just in the United States but in many countries.  

From an operational perspective, it will be difficult for irradiation to completely replace methyl bromide. Irradiation not a very good alternative for many methyl bromide fumigators,î said Al Marulli, a former USDA official and proprietor of Agricultural Trade Services, based in Chicopee, Mass. Not to say it canít be done, but they will have to figure out how to make money from it.î

There are three types of irradiation technologies used for phytosanitary purposes: electron beams, X-rays and gamma rays. While each technology operates a little differently, the amount of radiation used is minimal.

There are four major builders of irradiation equipment: Graystar, MDS Nordion, Reviss Services and IBA. Irradiation units are generally sold to companies involved in product treatment activities.

After much evaluation, Securefoods decided to pick GrayStar units for its Brazil venture. GrayStarís Genesis unit cost about $2 million apiece and, if all the government permits are together, can be installed in less than six weeks, according to Martin Stein, GrayStarís chief executive.

Recent illnesses linked to bacteria on imported fruits and vegetables have left many people concerned about the effectiveness of currently prescribed pre-shipment treatments. A 1969 salmonella outbreak in the United Slates was linked to Brazilian mangoes, which according to import records were treated by hot water dip to kill Mediterranean fruit flies. The U.S. Center for Disease Control and Prevention (CDC) traced the shipment back to a single farm in Brazil. Investigators found that the dip tanks on the tam, were ìunclosed, and toads, birds, and droppings of bird feces were noted in or near the tanks,î CDC also found that dipping mangoes too quickly between hot and cool water tanks causes the fruit to contract, encouraging pathogens to enter through the skin.

The USDA responded to this case by recommending that mango exporters adequately filter and chlorinate their dip tank water. The agency also asked these exporters to wait 30 minutes between the hot and cool water dips. Some industry experts believe hot water dip treatments should be replaced by new technology such as irradiation. ìHot water treatment has proven to be untrustworthy,î Karski said.

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