Comparison of selenite F, Muller-Kauffmann tetrathionate and Rappaport's medium for salmonella isolation from chicken giblets after pre-enrichment in buffered peptone water

Abstract

SUMMARYSix hundred and eighty three samples of chicken giblets were examined for salmonellas. Three hundred and forty nine of these were neck and crop specimens and 334 were combined liver and heart samples. Two hundred and ten, in all, contained salmonellas.The technique of examination included pre-enrichment in buffered peptone water at 37°C for 18 h and subculture to three enrichment media: MullerKauffmann tetrathionate, selenite F and Rappaport's magnesium chloride malachite green broth. Inocula from buffered peptone water to 10 ml of tetrathionate and selenite were 1 ml in each case. The inoculum from the pre-enrichment medium to 10 ml of Rappaport was 0 005 ml. Tetrathionate and selenite were incubated at 43°C for 48 h. Rappaport's medium was incubated at 37°C for 48 h. Subcultures from all three enrichment broths were made at 24 h and 48 h to brilliant green MacConkey agar. Selective agars were incubated at 37°C for 24 h.The most successful technique for salmonella isolation used Rappaport's medium, which was significantly more efficient than either tetrathionate or selenite. This finding reinforces results obtained using sewage polluted natural water as test material and it is suggested that routine examination of environment samples for salmonellas could be based on Rappaport's medium alone.If S. typhi, S. dublin or subgenus III salmonellas were likely to be present in the sample, the technique described here would require modification.

A comparison of the original Rappaport medium (R medium) and the Rappaport–Vassiliadis medium (RV medium) in the isolation of salmonellae from meat products

“…The findings concerning the R25 medium were confirmed by Harvey, Price & Xirouchaki (1979), Harvey & Price (1981, 1982a and Fricker, Girdwood & Munro (1983). On the other hand, Alcaide et al (1982), using RV medium with the addition of novobiocin and van Schothorst & Renaud (1983), using RV medium made with soya peptone showed that the RV medium was significantly more efficient than selenite broth or Muller-Kauffmann tetrathionate broth (MK-ISO), respectively.…”

Comparison of methods for isolating Salmonella bacteria from faeces of naturally infected pigs

“…Use of BPW pre‐enrichment with faecal samples may be linked to the popularity of RV enrichment broth, which requires small inoculum volumes, or high inoculum ratios ( Harvey and Price 1980). Harvey and Price (1981) considered the need for high inoculum ratios to be an advantage when pre‐enrichment is used but, citing the example of pig faeces, a potential liability if direct inoculation with large amounts of material is desirable.…”

“…(1999) reported that recovery of Salmonella bacteria from swine faeces enriched in TTB tended to be reduced if pre‐enrichment in BPW was used. Studies with a range of materials have commonly found RV to be superior to tetrathionate broths when compared subsequent to pre‐enrichment ( Harvey and Price 1981; Rhodes and Quesnel 1986). The nature of the source material, the prevalent serotypes in the material, and the use of direct enrichment or pre‐enrichment, were recognized to be factors likely to influence the results of studies comparing enrichment media ( Harvey and Price 1981).…”

“…It has been suggested that there may be more media and culture methods for the isolation of Salmonella bacteria than for any other bacteria ( Waltman 1998). A plethora of studies have compared microbiological techniques for isolating Salmonella bacteria from diverse materials, and conflicting findings among studies abound ( Harvey and Price 1981; D'aoust 1989; Busse 1995). The scope of this methodological dilemma was highlighted in a survey of US veterinary laboratories culturing poultry tissue and environmental samples for Salmonella bacteria.…”

General Interest Scientific and Teechnical Factors Affecting the Setting of Salmonella Criteria for Raw Poultry: A Global Perspective

“…The ‗gold standard' for Salmonella detection in food follows a standard protocol of nonselective pre-enrichment, selective enrichment, isolation on selective agar media and biochemical and serological confirmation. Choice of enrichment broth, incubation temperature, inoculum ratio and plating media affect the Salmonella detection limit (17,34,45,51,83,84,141,143,160,193). Numerous cultivation methods that are commonly used in Salmonella surveillance and outbreak investigations vary significantly in sensitivity and specificity (30,45,63,120,164,193).…”