Staphylococcus aureus strains with similar biotype characteristics occur in meat products and in the anterior nares of workers in slaughterhouses and meat‐processing plants. Such strains are rare in humans not in frequent contact with meats. The biotype is staphylokinase‐negative, β‐haemolysin‐negative, bovine plasma coagulase‐negative, crystal violet type A and Protein A‐positive. Most strains of this biotype belong to phage group II or are not typable with the international set for typing Staph. aureus of human origin.

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Staphylococcus aureus isolated in Belgium and Zaire from food and from various sources in the meat industry were biotyped, phage typed and tested for staphylococcal enterotoxin (SE) production. Thirty of the 185 strains examined produced one or more SE, and 23 of these belonged to the human biotype. Most SE-positive strains belonged to phage groups TI1 and Mixed, or were not typable. None of the poultry-like biotype strains, which were frequent in nasal carriers among workers in meat plants as well as in minced meat, produced enterotoxins. Avian biotype strains similarly were negative.

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A plate method for enumerating Staphylococcus aureus is described which combines a 1‐h recovery period for stressed cells on a relatively non‐selective Baird‐Parker agar base followed by a 24‐h growth phase in a highly selective, supplemented Baird‐Parker medium added as an overlay. Tests with pure cultures showed satisfactory recovery of stressed Staph. aureus and other bacteria. Similar results were obtained with the conventional Baird‐Parker procedure and with the two‐stage isolation method for shrimps and poultry neck skins, but for raw minced meat, recoveries were higher with the combined method than with the conventional medium. All colonies visible after 24 h on the two‐stage medium can be counted as Staph. aureus, whereas longer incubation times and confirmatory tests are necessary to differentiate it from other organisms on conventional Baird‐Parker medium.