R. W. Griffith

Impact of commercial preharvest transportation and holding on the prevalence of Salmonella enterica in cull sows.

The objective of this study was to examine the prevalence of Salmonella enterica in cull sows at various stages from the farm to the abattoir. Cull sows (n=181) were sampled over 10 weeks. Fecal samples (10 g each) were collected on the farm ca. 24 h before loading and at the live-hog market ca. 3 h before loading. Samples (ileocecal lymph nodes, cecal contents, feces from the transverse colon, ventral thoracic lymph nodes, subiliac lymph nodes, sponge swabs of the left and right carcass sections, and chopped meat) were collected at the abattoir. The percentages of positive fecal samples on the farm and at the live-hog market were 3% (5 of 181 samples) and 2% (3 of 181 samples), respectively. After transport from the live-hog market (10 h) and holding at the abattoir (6 h), 41% (74 of 180) of cull sows yielded S. enterica in one or more sampled tissues. The isolation rate for total cecal contents (33%; 60 of 180 samples) was significantly (P<0.05) higher than those for ileocecal lymph nodes (7%; 12 of 181 samples), feces (11%; 20 of 181 samples), and ventral thoracic and subiliac lymph nodes (2%; 4 of 181 samples). Before a 2% lactic acid carcass wash (lasting 8 to 9 s), 14% (25 of 180) of carcasses were positive, compared with 7% (12 of 179) after the wash (P<0.05). Two S. enterica serotypes, Derby and Infantis, were found on the farm and at the live-hog market. At the abattoir, 12 serotypes that had not previously been found on the farm or at the live-hog market were recovered. The results of this study demonstrate that transport and holding practices may contribute to an increase in S. enterica infection prior to slaughter to levels much higher than those found on the farm.

Effect of Short-Term Lairage on the Prevalence of Salmonella enterica in Cull Sows†

This study was designed to compare Salmonella enterica prevalence in sows held in a holding pen at the abattoir for approximately 2 h (hold sows) with sows slaughtered immediately after transport to the abattoir (no-hold sows). Cull sows (n = 160) were sampled from four sampling periods over 8 weeks (February to March 2002) at the abattoir. Sows originated from an integrated swine farm and were sent to a live-hog market and then to the slaughter facility. Before testing, sows entered the abattoir pen and four 100-cm2 four-ply gauze squares were placed randomly on the pen floor for S. enterica culture. Sows were alternatively assigned to the hold or no-hold group. Samples collected from sows during slaughter were ileocecal lymph node, cecal contents, transverse colon contents, subiliac lymph node, sponge swabs of the left and right carcass section (300 cm2), and chopped meat. Overall, S. enterica was isolated from 44% (35 of 80) of the no-hold sows, which was significantly less (P < 0.05) than 59% (47 of 80) of the held sows. Also, no-hold sows had a lower cecal content prevalence (39%, 31 of 80) compared with that (55%, 44 of 80) of held sows (P < 0.05). S. enterica serovars isolated from no-hold sows were Brandenburg (n = 16), Derby (n = 12), Hadar (n = 8), Infantis (n = 6), Johannesburg (n = 3), 6,7:z10-monophasic (n = 3), and Typhimurium (n = 1). S. enterica serovars isolated from held sows (n = 61 isolates) were Derby (n = 19), 6,7: z10-monophasic (n = 15), Brandenburg (n = 10), Infantis (n = 6), Hadar (n = 5), Johannesburg (n = 4), and Tennessee (n = 2). Serovars recovered from the pen were Reading (n = 6), Derby (n = 4), Uganda (n = 2), and Manhattan (n = 2). Results of this study suggest that holding pens contribute to increased S. enterica carriage in cull sows. Abattoir holding pens might be an important control point for S. enterica in the ground pork production chain.

Low Prevalence of Listeria monocytogenes in Cull Sows and Pork

The goal of this study was to determine the prevalence of Listeria monocytogenes in sows slaughtered at a single Midwestern plant on two occasions (trial 1, n = 179 sows; trial 2, n = 160 sows). Fecal samples collected antemortem (trial 1) as well as animal tissues, and carcass swabs collected at the abattoir (trials 1 and 2) were analyzed. Eight isolates of L. monocytogenes were recovered from five samples that represented 0.18% of the total samples (n = 2,775). In trial 1, L. monocytogenes was detected in a tonsil sample (0.6%; 1 positive of 181 tonsils), in a carcass (0.6%; 1 positive of 179 carcasses), which was sampled prior to the organic rinse, and in two chopped meat block samples (1.2%; 2 positive of 165 samples). In trial 2, L. monocytogenes was only detected in a single chopped meat block sample (0.15%; 1 positive of 688 total samples). These data indicate the low prevalence of L. monocytogenes in the cull sow.

Salmonella enterica serovar typhimurium colonization of the crop in the domestic turkey: influence of probiotic and prebiotic treatment (Lactobacillus acidophilus and lactose).

Abstract Acute colonization of the crop of the domestic turkey by Salmonella enterica serovar typhimurium (ST) was examined. The influences of preharvest probiotic and prebiotic treatment with lactobaccilli and lactose on crop colonization with ST were also investigated. Prior to Salmonella challenge, poults received 2.5% lactose and Lactobacillus acidophilus (1.9 × 109 organisms/liter) in the only source of drinking water from 1 day old to termination. At 3 wk old, turkey poults were challenged with ST (1.7 × 108 colony-forming units [CFU]/ml) before their natural nocturnal fast to determine the potential effects of supplementation on crop colonization when the crop was engorged and subsequently undergoing emptying. Crop ingesta and tissue were collected at time points 30 min and 4, 8, and 24 hr postchallenge and ST levels were determined. High levels of ST were detected in the crop. For instance, for the poults not receiving lactose or lactobacilli, 30 min after ST challenge, there were 4.4 × 107 CFU in the crop ingesta and 5.3 × 105 CFU in the crop wall. Ingesta ST levels dropped dramatically to 1.0 × 106 CFU after 4 hr as the crop emptied. Crop wall ST levels were steady during the nocturnal crop evacuation. Immunohistochemical staining demonstrated ST in close association with the crop epithelium. Treatment with lactose and L. acidophilus supplementation did not reduce ST colonization.

Postmortem detection of acute septicemia in broilers.

Septicemia is an unwholesome condition diagnosed during postmortem inspection in poultry slaughter establishments on the basis of macroscopic lesions. Early identification of septicemia has important public health implications. In this study, Pasteurella multocida, Escherichia coli, and Staphylococcus aureus septicemia were induced in broilers in order to determine if lesions of acute septicemia can be grossly detected in the visceral organs of broiler carcasses prior to the development of changes in the skeletal muscle. Increased spleen and liver weights were observed during the acute phase of septicemia. Airsacculitis, pericarditis, and perihepatitis were observed during the acute phase of P. multocida- and E. coli-induced septicemia; and arthritis was the earliest indicator of S. aureus-induced septicemia. These macroscopic lesions were sufficient to identify unwholesome septicemic broiler carcasses prior to the development of changes in the skeletal muscle of the carcass.

Slatted pen floors reduce Salmonella in market swine held in abattoirs

The objective of this study was to directly compare Salmonella isolation rates from pig slaughtered after ~ 4 hours holding on slatted or solid concrete floors. Seven truckloads (replicates) of market swine (~ 120 kg) from a fully integrated farrow-to-slaughter operation were studied. At unloading, groups of pigs (15-30) were sorted to 1) no-hold (20-45 minutes waiting), 2) pens with solid concrete floors (~ 4 hours), 3) slatted concrete floors (~ 4 hours). Postmortem samples were cultured for Salmonella. Those pigs held in pens with slatted floors (63.6%) had significantly (P < 0.05) less Salmonella in their ceca than those held on solid floors (72.7%).

Effects of egg antibody to components of inflammatory activation (phospholipase a 2 and Toll like receptor 4) on the response of young turkeys to Salmonella typhimurium challenge

The effect of passive immunization against two components of the inflammatory response (Toll-like receptor 4 and phospholipase A2) was examined in turkey poults receiving a challenge with Salmonella enterica serovar typhimurium (ST). The number of ST in the crop ingesta were not influenced by prior oral administration of egg antibody against Toll-like receptor 4 and phospholipase A2. There was a marked effect of the passive immunization on the crop contents 48 hours following ST challenge. The crops of the ST challenged non-immune sera controls were distended and fluid filled while those of poults receiving egg antibody contained ingesta. The dry weights of the ingesta in the crop of the ST challenges non-immune egg immunoglobulin receiving birds were 510% those receiving egg antibody to Toll-like receptor 4 or phospholipase A2. It is concluded that fluid accumulation in the crop of the young turkey following ST challenge may be a good model for bacterial enteric diseases where there is profuse watery diarrhoea. Moreover, passive immunization with antibody to Toll-like receptor 4 and phospholipase A2 reduces the symptoms associated with salmonellosis and possibility other enteric diseases.