The occurrence and significance to animal health of salmonellas in sewage and sewage sludges

Abstract

SUMMARYA total of 882 samples of settled sewage, sewage sludges and final effluents from eight sewage treatment plants were examined for the presence of salmonellas.Of these samples 68 % were positive, isolations being made most frequently from settled sewage (85 %), raw sludge (87 %) and anaerobically digested sludge (96 %).Fewer isolations were made from final effluent (24 %) and processed sludges (58 %). Samples usually contained less than 200 salmonellas/100 ml and arguments are presented that such concentrations should not lead to disease in animals if suitable grazing restrictions are followed.

Quantification and characterization of Salmonella spp. isolates in sewage sludge with potential usage in agriculture

“…in sewage sludge worldwide, even in those which undergo the same treatment process (mesophilic anaerobic digestion). In the present study, the frequency of positive samples were above DL (<0.006473 MNP/g) in 38.9% (21/54) of the samples analyzed, which was below the figures derived from other studies [ 22 ] and [ 23 ], which registered 92 - 100% (n =91) and 58% (n =24), respectively. The highest concentration of Salmonella spp.…”

Multiyear study of sludge application to farmland: prevalence of bacterial enteric pathogens and antibody status of farm families

“…In studies directed to the determination of the most probable containing as few as 0.3 salmonellae CFU/100 ml. The We are unable to relate the higher number of isolations method used by Jones and his colleagues (15) was much from the Columbus plant during the first quarter of each year more extensive than ours in that multiple enrichment systo any specific condition at the plant. Carrington et al 3tems were used.…”

“…Similar results have cheese. In another case, Lang et al (17) reported that 15,000 been obtained by Danielsson (6), Dudley et al (9), and Jones cells of Salmonella cubana were required for illness in et al (15). The rate of isolation depends on the initial number patients ingesting contaminated carmine dye.…”

A note on potential hazards to animals grazing on pasture improperly treated with sewage sludge

“…Sewage sludge is a useful fertilizer which contains humus and nutrients and may be used on either arable land or pasture. When it is used on pasture however, there is a possible health risk to animals because many samples of sewage sludge contain pathogenic micro-organisms, especially salmonellas (Wray 1975;Jones et al 1980). This potential hazard was studied by Hall & Jones (1978), who fed cattle on sludge, and by Argent et al (1981), who grazed lambs on pasture that had been sprayed with sludge.…”