ICMSF methods studies. X. An international comparative study of four media for the enumeration of Staphylococcus aureus in foods

Abstract

An international comparative study, undertaken by six laboratories to assess the performance of four selective media commonly used for the enumeration of Staphylococcus aureus in foods, revealed that Baird-Parker agar performed most satisfactorily. There was no significant difference among milk salt, tellurite polymyxin egg yolk, and kalium rhodanid - actidione - natriumazid - eigelb - pyruvat (KRANEP) agars. The type of food examined appeared to influence the performance of the media, but no specific patterns could be determined. Cultures yielding 3+ and 4+ coagulase reactions are most likely to possess thermostable nuclease activity, and are therefore most likely to be S. aureus.

Enumeration of Vital and Thermally Stressed Staphylococcus aureus in Foods Using Baird‐Parker Pig Plasma Agar (BPP)

“…In comparative studies of many different media (Crisley et al 1965;Collins-Thompson et al 1974;Stiles & Clark 1974;Hurst et al 1976;Stadhouders etal. 1976;Andrews & Martin 1978;Niskanen & Aalto 1978;Rayman et al 1978), the medium of Baird-Parker (BP) (1962) containing tellurite and egg yolk has invariably proved to be superior or at least as good as the other media under test. Unfortunately, identification is not conclusive as both egg yolk positive and negative colonies may prove to be Staph.…”

Comparative studies of selective media for recovery of Staphylococcus aureus from natural waters

“…aureus from water samples. The results obtained show that Columbia-CNA agar, Polymyxin Staphylococcus agar, Baird-Parker modified agar, Crisley-TPEY agar, Giolitti-Cantoni agar, Vogel-Johnson agar and the BFR media modifi cations 2, 3,4, 5, 6, 8,9, 10, 11, 12, 14, 15, 16, 17 Martin (1978), Rayman et al (1978) and Alico & Dragonjak (1986). As can be seen, BFR-0 and BFR-13 agars were the only media selective for the Staphylococcus strains tested, inhibiting the growth of Gram-positive rods (spore-formers), some enterobacteria and yeasts, which are frequently isolated on staphylococcus media.…”

“…These results are in agreement with those obtained in the present study ( Table 1). Rayman et al (1978), using Baird-Parker, KRANEP, Milk-Salt and TPEY media for isolation of staphylococci from food samples, obtained the highest selective counts on Baird-Parker agar, although there was a great variability in the results obtained by the different laboratories. These results should not be considered inconsistent with those reported here,…”

“…aureus ranged between 10.5% for Giolitti-Cantoni agar and 63.2% for KRANEP agar and positive verification of non-typical colonies percentage ranged between 0% for Baird-Parker agar and 25.6% for KRANEP agar ( Table 5). These results differ slightly from those obtained by Rayman et al (1978) for KRANEP agar in food samples with a confirmation percentage of 69.8% and those obtained by Olivieri & Riggio (cited by Evans 1977) for m-Staphylococcus medium in which less than 10% of the typical colonies proved to be Staph. aureus.…”

Design and performance of a new medium for the quantitative recovery of Staphylococcus aureus from recreational waters

“…The other organisms growing on the selective media were Gram-positive or Gram-negative rod-shaped bacteria, mainly Bacillus spp. and Proteus spp., although the media also permitted the growth of other Gram-positive cocci (Evans 1977;Rayman et al 1978). For this reason, the first objective in the research of a new medium for enumeration of staphylococci from water samples and other sources was the study of substances that inhibited or reduced the numbers of organisms other than staphylococci.…”