USDA research yields big results in food safetyUSDA research yields big results in food safety
Overview of USDA research efforts highlights new discoveries in food safety, including against salmonella and campylobacter.
July 21, 2017

U.S. Department of Agriculture research generated 244 new inventions and 109 patent applications in the 2016 fiscal year. These innovations included an anti-cancer drug derived from omega-3 fatty acids, sensors to help prevent bridge collapses, gene-silencing technology that controls mosquito populations and handheld imaging tools to detect meat contamination.
Secretary of Agriculture Sonny Perdue released USDA’s annual "Technology Transfer Report," which lists the technology produced through research either conducted or supported by USDA.
“USDA’s made-in-America research gives us new technology that creates business opportunities and private-sector jobs in both agriculture and other sectors,” Perdue said. “Studies show that every dollar invested in agricultural research returns $20 to our economy. Just like the crops that come up out of our soil, these inventions and innovations were made in America.”
The 559-page report outlines the public release and adoption of information, tools and solutions developed through USDA’s agricultural research efforts, collaborative partnerships and formal cooperative research and development agreements. Find the full report at www.usda.gov/sites/default/files/documents/usda-fy16-tech-transfer-report.pdf.
Food safety discoveries
Researchers with USDA's Agricultural Research Service (ARS) in Beltsville, Md., developed a handheld fluorescent imaging device (HFID) that detects contaminated food and equipment surfaces. This patented technology is under license and commercial development by an industry partner and will support and improve industry and government meat safety inspection programs.
ARS demonstrated that the current Food Safety & Inspection Service (FSIS) protocol for salmonella testing of whole chicken carcasses may potentially lead to carryover of intervention solutions -- which are used to reduce pathogens in poultry processing -- into the collection broth tested by FSIS inspectors. This carryover could result in underestimating salmonella levels in poultry processing operations.
ARS scientists in Athens, Ga., developed a modified collection broth capable of neutralizing a wide range of sanitizers, which resulted in a statistically more accurate reporting of salmonella in poultry processing. FSIS subsequently validated and approved this new modified collection broth for regulatory sampling. In July 2016, FSIS field inspectors implemented the new protocol in their collection of samples for salmonella testing.
Also in Athens, ARS scientists optimized a novel in-package ozonation technology to reduce campylobacter contamination on chicken breast fillets. The scientists noted significant reductions of natural bacterial flora and surface-applied bacterial pathogens (Campylobacter jejuni) when using this technology. Currently, this technology is being expanded to include major food quality (Pseudomonas fluorescens) and additional food safety (Salmonella spp.) microorganisms. This novel technology will provide commercial processors with a method to significantly reduce bacterial pathogens and other bacterial flora on packaged breast fillets and increase the quality and safety of the final product as it leaves the processing plant.
ARS researchers in College Station, Texas, have identified a population of roosters from the Athens Canadian Random Bred lineage, a 1950s meat-type chicken, with differential expression of key immune markers to serve as sires for the generation of an F1 population of chickens selected for a more efficient innate immune responsiveness. ARS is attempting to breed chickens with natural resistance to salmonella and campylobacter by using older original chicken populations with greater genetic diversity to produce more pathogen-resistant broilers. Development of microbial pathogen-resistant birds would be a dramatic success in enhancing the microbial safety of poultry meat products reaching the consumer.
Improving milk’s shelf life
Pasteurization has long been the standard method to extend the shelf life of dairy products as well as a means to reduce the microbial load and the risk of foodborne pathogens. ARS-funded scientists at the Center for Food Safety Engineering (CFSE) at Purdue University in West Lafayette, Ind., tested a novel pasteurization method whereby milk is dispersed in the form of droplets and treated with low heat/pressure variation over a short treatment time.
This low-temperature, short-time (LTST) method was very effective in reducing the level of microorganisms up to 100 million-fold. The CFSE-developed BARDOT/BEAM technology was used to demonstrate that only very few organisms (bacillus species) that do not grow at refrigeration temperatures were able to survive LTST treatment. The LTST process extended the shelf life of the milk from a maximum of 35 days to approximately 63 days. The improved shelf life will have a positive impact on the dairy industry in terms of shipping and overall sustainability.
Antimicrobial resistance
ARS scientists in Clay Center, Neb., compared the populations of antimicrobial-resistant bacteria and the presence of antimicrobial resistance genes within samples of livestock and municipal waste streams discharged from municipal wastewater treatment facilities, cattle feedlot runoff catchment ponds, swine waste lagoons and environments considered low impact (a municipal lake and a prairie).
The results showed that the prevalence and concentrations of antimicrobial-resistant bacteria were similar among the livestock and municipal sample sources, but there were differences among the antimicrobial resistance genes found in agricultural, environmental and municipal samples, with municipal samples harboring the highest number of antimicrobial resistance genes.
It was concluded that antimicrobial resistance is a very widespread phenomenon that can be found in cattle, swine and human waste streams, although a higher diversity of antimicrobial resistance can be found in human waste streams. This study indicates that antimicrobial-resistant bacteria are widespread and that humans are a reservoir of resistant bacteria for other humans. This was previously unknown and indicates that agricultural systems are not the only source of antimicrobial resistance.
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