CategoryPre-Harvest Pork Safety
Date Full Report Received07/08/2009
Date Abstract Report Received07/08/2009
Funded ByNational Pork Board
Salmonellosis continues to be an important foodborne disease in the U.S. and worldwide. Even though illness caused by salmonellae is usually not very severe, there are such a large number of cases that salmonellosis has an estimated five fold greater economic impact than illness caused by E. coli O157:H7.
Overall objective of this project was to summarize historical and epidemiological data published in the scientific literature on the relationships between food and non-food vehicles and vectors and human illnesses caused by Salmonella.
Scientific literature databases, U.S. government publications, relevant government publications/regulations from other countries, industry information and other internet sources were searched for information on outbreaks and epidemiological studies of human illness attributed to Salmonella spp. until December 2008. Data were also collected on important government regulations and industry initiatives to control this organism.
Information was presented in a 51-page white paper with 485 references describing epidemiology, surveillance, regulation, and industry initiatives to control Salmonella. Data on 501 outbreaks (1992-2008) were tabulated chronologically in an appendix to the white paper. Outbreak data were also organized in tables presenting information on the largest outbreaks (>200 cases), vehicles of infection associated with different Salmonella serotypes, and Salmonella serotypes associated with different vehicles. Figures were generated to display importance of different vehicles.
Data were discussed in the text with reference to: (a) reservoirs of these bacteria, (b) routes of human infection, (c) relationships between food and non-food vehicles and vectors, (d) factors important in causing illness, (d) government regulations, (e) industry initiatives and (f) surveillance strategies.
Of the outbreaks with known or suspected vehicles, 37% of outbreaks and 34% of cases were traced to meat and meat products. Some other outbreaks associated with combination foods (lasagna, sandwiches, pot pies, etc.) may also have been caused by contaminated meat. Of the meat outbreaks, pork was associated with 30% of outbreaks, 36% of cases. In addition to outbreaks associated with pork meat, ham, and sausage, there were outbreaks among people handling pig ear dog treats. S. Typhimurium was by far the most common of the 12 serotypes associated with pork products. Poultry products were associated with 33% of meat outbreaks and beef products with 18%. Outbreaks and cases of salmonellosis associated with fresh fruits and vegetables have become more common.
About 65% of Salmonella isolates from turkeys and swine are resistant to at least one antibiotic compared to 30-40% of isolates from chickens and cattle. Data indicate that prevalence of antibiotic sensitivity in Salmonella from turkeys, swine, and cattle has decreased between 1999 and 2006. However, resistance to multiple antibiotics has increased, particularly in S. Typhimurium and S. Newport.
Some industry interventions, such as improved hide cleaning processes, have reduced salmonella contamination of animal carcasses. Some European countries have undertaken well organized, nationwide programs to control Salmonella in poultry and swine.