Swine can carry Salmonella strains that may be transmitted to humans by pork products. This investigation determined the distribution and types of Salmonella in 12 swine finishing herds and a slaughter facility in Santa Catarina, Brazil. A total of 1258 samples, consisting of environmental, feed, carcass, lymph node, and fecal material were collected and submitted to bacteriological isolation of Salmonella. From 487 positive samples, 1255 isolates were recovered and confirmed to be Salmonella. The distribution of positive samples was as follows: finishing pen floors 26% (16/61); feed 29% (42/143); feces 44% (52/119); pooled feces 59% (35/59); slaughter holding pens 90% (36/40); lymph nodes 46% (220/478); pre-chilled carcass surfaces 24% (24/98); and post-chilled carcass surfaces 24% (62/260). The most prevalent serovars were Typhimurium, Panama, Senftenberg, Derby, and Mbandaka. By pulsed-field gel electrophoresis, 1071 isolates were subtyped using XbaI, and duplicate isolates were removed. From the remaining 747 isolates, 163 macrorestriction profiles (pulsotypes) were identified. Six pulsotypes were considered very frequent, occurring in 33 isolates or more. The multiple correspondence analyses showed correlations between pulsotypes from shedding pigs (feces), herd environment (pen floors), and subiliac and prescapular lymph nodes and between lairage and carcass surface samples before and after chilling. All sources of Salmonella investigated contributed to the carrier state; however, pre-slaughter contamination at lairage was the variable most strongly associated with carcass contamination. A total of 59 different antimicrobial resistance profiles were observed in 572 Salmonella isolates. From these isolates, 17% (97/572) were susceptible to all 15 antibiotics tested, 83% (475/572) were resistant to at least one, and 43% (246/572) were resistant to four or more antibiotics (multi-resistant). The AmpGenKanTet profile was the most prevalent in carcass isolates and was associated with farm origin.

The effect of organic acids and mannanoligosaccharide addition to the diet was assessed in pigs orally inoculated with Salmonella typhimurium. Forty-six growers were distributed among four treatments: Basal Diet (BD); BD+encapsulated organic acids; BD+free organic acids; BD+mannanoligosaccharide. Seroconversion was monitored, and feces and tissue samples were tested for Salmonella isolation. No treatment prevented the carrier state, but a tendency of lower fecal excretion was observed in the group treated with mannanoligosaccharide.

A transmissão de Salmonella na cadeia produtiva de suínos é um problema de difícil controle. O objetivo do estudo foi avaliar o efeito da administração oral de probiótico sobre a ocorrência de infecção e excreção fecal de Salmonella em suínos em fase de crescimento. Os tratamentos consistiram de ração basal sem aditivos (controle) ou adicionada de probiótico (10(7)ufc g-1 de células viáveis dos gêneros Bifidobacterium, Enterococcus, Lactobacillus e Saccharomyces). Foram alocados seis leitões de 50 dias em cada tratamento, com duas repetições por tratamento. Todos os animais foram inoculados com Salmonella Typhimurium (10(6)ufc mL-1) após 14 dias do alojamento. Semanalmente, foram coletadas amostras de sangue e fezes e no dia 35 pós-inoculação os animais foram sacrificados e necropsiados. Os animais de ambos os tratamentos foram infectados por Salmonella e soroconverteram. Não houve diferença (P>0,05) entre os grupos nas médias de Salmonella, Enterococcus, Lactobacillus e coliformes totais nas fezes, porém a administração de probiótico resultou em menor frequência de isolamento de Salmonella a partir de fígado (P=0,04), linfonodos mesentéricos (P=0,04), pulmão (P=0,03) e baço (P=0,01). Conclui-se que os microrganismos probióticos testados não foram capazes de impedir a infecção ou a excreção fecal de Salmonella em suínos de crescimento, mas diminuíram o número de portadores em linfonodos mesentéricos.

Salmonella is worldwide related to the most cases of food poisoning in humans. The meat contamination may occur from direct or indirect sources during the slaughter and pork processing. The main factors that contribute to pig carcass contamination at the slaughterhouse are the presence of asymptomatic Salmonella shedders and Salmonella transmission during the pre-slaughter transport and lairage. Usual slaughter procedures may be not able to totally avoid the contamination of the surface of carcasses. Therefore, the aim of this study was to test different treatments to reduce Salmonella contamination, which may be adopted for decontamination of pig carcasses. Skin samples from pigs were artificially contaminated with a Salmonella Typhimurium phage type DT144 suspension (106 CFU/mL), and afterwards underwent nine treatments: 1) water, 2) water at 80°C, 3) water at 80°C with an organic acids blend (ascorbic, citric and lactic, Citrex ®), 4) chlorinated water at 80°C with acids, 5) chlorinated water at 80°C, 6) water with acids, 7) chlorinated water with acids, 8) chlorinated water and 9) negative control (no treatment). Concentrations of 1,000 ppm and 2 ppm of Citrex ® and chlorine, respectively, were used. All treatments were performed in ten repetitions and applied under controlled pressure (3 atm) for 10 seconds. Each skin was sampled, by swabbing a 5cm²-area on three occasions: before, shortly after and 24 hours after treatment. Swabs were placed individually in Buffered Peptone Water, homogenized, and 100 µL were spread on XLD agar for colony-formation unit counting of Salmonella. Data were analyzed using repeated measures model by the MIXED procedure of SAS. The effects of block, treatment, time and the interaction between them were tested. The treatment with chlorinated water at 80°C with organic acids had the best performance immediately after treatment and 24 hours later, followed by the treatments with chlorinated water plus organic acid, and water with organic acid.