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According to a new report by global independent product-testing organization Consumer Reports, a strain of Salmonella matching the one associated with the current multi-state Salmonella outbreak has been found in samples of raw chicken manufactured by California-based Foster Farms.

The Salmonella outbreak that the U.S. Department of Agriculture (USDA) and the Centers for Disease Control and Prevention (CDC) are investigating has so far affected about 300 people in 17 states. Consumer Reports would not typically make its findings publicly available, but in this case the information may be of importance to the investigation, the organization said.

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Despite the large-scale outbreak Foster Farms has refused to start a recall, which prompted the USDA to threaten to close down the three facilities in Fresno and Livingston which have been linked to the outbreak, NBC News reported. According to the news source, the USDA sent a letter to the company president Ron Foster on Tuesday, warning that Foster Farms had until October 11 to present an action plan to improve sanitary conditions and safety measures at the plants or face a shutdown.

This particular strain of the bacteria — Salmonella Heidelberg — is characterized by a higher rate of hospitalization and is among the most serious types of Salmonella because it is resistant to many antibiotics, the NBC said.