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posted on Monday, April 13, 2009 4:35 PM


April 13 2009 (FoodBizDaily) - Of late, in the news, some pistachio and peanut-butter brands have been blacklisted as being contaminated with Salmonella.  First, it was reported that some US peanut-butter brands were tainted. After a while, reports of samples from two of the local brands as being contaminated came in. At present, the news is that it’s pistachio nuts, primarily from the US, that have the contamination; however, as a precautionary measure, there was voluntary recalling of the majority of the brands from the market.

According to reports by the US Department of Agriculture (USDA), many of the commonly occurring food-borne illnesses are often caused by the Salmonella bacteria; this report is given in the USDA’s website fact sheet. It’s imperative that we adopt a complete farm-to-table approach to food safety if we are hoping to bring down Salmonella infection, or salmonellosis, as it is termed. Farmers, food industry, food inspectors, retailers, food-service workers, and consumers are all critical links in the chain of food-safety.

More than 2,300 serotypes of bacteria make up the Salmonella family. These serotypes are one-celled organisms and are too tiny to be seen by the naked eye, that is, without a microscope. Of these, the Salmonella Enteritidis and Salmonella Typhimurium are the two types that cause about half of all human infections; these two are also the most common types found in the United States.

It’s the intestinal tract of human beings and other animals, birds included, that forms the home of Salmonella. Transmission to human beings normally occurs through the consumption of food contaminated with animal feces. Salmonella is heat-sensitive, and, therefore, would be able to survive if present in raw meat and poultry if the product is undercooked, or not cooked to a safe minimum internal temperature, according to the USDA.

Cross-contamination is another way in which salmonellosis can be caused by the bacteria. This occurs when Salmonella gets transmitted by direct contact of ready-to-eat foods, such as salads, with juices from raw meat or poultry.The Salmonella bacteria have been found to be causing illnesses for more than a century now. It was Dr Daniel E. Salmon, an American scientist, who discovered the bacteria.

The Philippine Nuclear Research Institute (PNRI) suggests the use of irradiation as one of the effective interventions to save food from contamination by the Salmonella bacteria.

Zenaida de Guzman, who heads PNRI’s biomedical research section and is the project leader of food-irradiation research and development project, is of the opinion that in combination with Good Manufacturing Practices and Hazard Analysis and Critical Control Points, irradiation should be used as a means to eliminate pathogenic microbes in food items.

“We want the public to know that we use this technology [irradiation] to eliminate microbes, such as Salmonella, E. coli and Listeria in food,” the BusinessMirror reported as de Guzman stating to the magazine in an interview.

De Guzman, however, was quick to add that it would not be possible any more for the PNRI to irradiate the pistachio and the peanut butter which were, in recent times, found to be contaminated or still suspected to be so with Salmonella.

She clarified further that it’s only raw agricultural stuff that can be irradiated, such as the raw pistachio or the raw peanut in the peanut butter. The finished products have already gone through an extensive process, right from planting to harvesting, and then drying, processing, and finally transporting; contamination might have taken place at any or all of these processes, or it could be that the toxins have already been built up.

“Agricultural raw materials have many sources of microbial contamination, including water,” she pointed out. In addition, she said, there are some protocols that have to be followed during food irradiation These include irradiation of the raw food materials immediately after the drying process which follows the harvest; this is to make sure that the growth of any more microbes is prevented. She added that in the event that the food material has a large amount of microbes present in it, there would be a need for a bigger dose of irradiation, which may have an effect on the quality, color, or taste of the produce.

However, de Guzman was of the opinion that Filipino food manufacturers should ensure that their products are free from bacteria that cause disease by seriously considering irradiation as the solution.

According to a PNRI flyer, irradiation is a process that makes use of high-energy ionizing radiation to minimize post-harvest losses, disinfest agricultural commodities including fresh fruits, prolong the shelf life of food and agricultural products, such as vegetables, fruits, fish, seafood, meat, and poultry, and decrease microbes that cause loss by spoilage and do away with pathogenic microbes.

Irradiation uses doses from 300 Gray (Gy) to 1,000 Gy, depending on the food product that has to be irradiated. Because irradiation leaves no radioactive residue on the product, the final product is safe for human and animal consumption, clarified de Guzman. "It is like putting the product under x-ray,” she said.

The PNRI’s set up its irradiation facility on a pilot-scale basis in the year 1984; later, in 2008, PNRI raised it to semicommercial scale. The facility is able to handle 2 tons of products per load. Dehydrated vegetables and spices, such as ground white and black peppers, powders like turmeric, cayenne, garlic, onion, ginger, chives, tamarind, and other condiments are irradiated at PNRI’s facility.

An increasing quantity of herbal products, such as malunggay and ampalaya powder, is being irradiated at the PNRI, added de Guzman. As also are frozen fruits for export, which are used for the making of ice cream.
In the PNRI facility, irradiation is also done to fresh garlic and onions in order to hold back sprouts. The facility also irradiates medical equipment, such as cotton, syringes, tubings, gauze, catheters, and orthopedic implants, for the purpose of sterilization.

In foreign countries, 80 percent make use of irradiation for sterilization, noted de Guzman. Even pet foods undergo irradiation in the United States.

Patties made for hot dogs, hamburgers, or even frozen chicken could also be subjected to irradiation.

Following a three-year study, it was confirmed that the whole of the Philippines was free of seed weevil. De Guzman announced that this could mean that soon the country may be exporting mango to the US. Already, Luzon and Visayas have been found to be free from seed weevil. A similar study was conducted in the Mindanao situation, the results of which are expected this year.

All the same, the mangoes meant for export to the United States will still be subjected to irradiation as a precautionary measure against fruit flies.Another prospective export opportunity is with China, de Guzman informed, as that country has shown interest in irradiated mangoes from the Philippines and the possible importation. - Staff writer


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