Prevalence and characterization of Salmonella in bovine lymph nodes potentially destined for use in ground beef.
A potential source of pathogenic bacteria in ground beef is the lymphatic system, specifically the lymph nodes. Bacteria have been isolated from the lymph nodes of cattle at slaughter; however, most studies have dealt with mesenteric lymph nodes, which are not normally incorporated into ground beef. The objective of the current study was to determine the prevalence and multidrug-resistance status of Salmonella in bovine lymph nodes associated with lean and fat trimmings that might be utilized in ground beef production. Bovine lymph nodes (n = 1,140) were collected from commercial beef processing plants. Half of the lymph nodes sampled were obtained from cull cow and bull processing plants, and the remainder were obtained from fed beef processing plants. Lymph nodes located in chuck and flank adipose tissue were collected for this study. Salmonella prevalence in the lymph node samples was low, with an overall prevalence of 1.6% and a 95% confidence interval of 0.85 to 2.3%. Lymph nodes from cull cattle carcasses had a higher prevalence of Salmonella than did those from fed cattle carcasses. Lymph nodes from the flanks of cow and bull carcasses had the highest prevalence at 3.86%, whereas lymph nodes from the chuck region of fed cattle carcasses had the lowest prevalence at 0.35%. Three of the 18 Salmonella-positive lymph node samples contained multidrug-resistant Salmonella, and all 3 samples were from cull cattle.
Arthur
Terrance M
TM
U.S. Department of Agriculture, Agricultural Research Service, Roman L. Hruska U.S. Meat Animal Research Center, Clay Center, Nebraska 68933-0166, USA. terrance.arthur@ars.usda.gov
Brichta-Harhay
Dayna M
DM
Bosilevac
Joseph M
JM
Guerini
Michael N
MN
Kalchayanand
Norasak
N
Wells
James E
JE
Shackelford
Steven D
SD
Wheeler
Tommy L
TL
Koohmaraie
Mohammad
M
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002417:Cattle / Q000382:microbiology*; D002418:Cattle Diseases / Q000382:microbiology / Q000635:transmission; D015169:Colony Count, Microbial; D024881:Drug Resistance, Bacterial; D024901:Drug Resistance, Multiple, Bacterial; D005506:Food Contamination / Q000032:analysis / Q000517:prevention & control; D005525:Food-Processing Industry / Q000592:standards; D006801:Humans; D008198:Lymph Nodes / Q000382:microbiology*; D008461:Meat Products / Q000382:microbiology*; D008826:Microbial Sensitivity Tests; D015995:Prevalence; D012475:Salmonella / Q000187:drug effects / Q000302:isolation & purification*; D012481:Salmonella Infections, Animal / Q000382:microbiology / Q000635:transmission
D000900:Anti-Bacterial Agents