Staphylococci in Cottage Cheese1

The Effect of Recovery Medium on the Isolation of Staphylococcus aureus after Heat Treatment and after the Storage of Frozen or Dried Cells

“…The recovery of heat shocked cells of S. aurew and other organisms has been studied by a number of workers. Busta & Jezeski (1961 found that heat treated S. aurew grew poorly on 110 medium and this was confirmed by Mickelsen et al (1963) who studied the recovery of staphylococci from cottage cheese. Busta and Jezeski also found that by reducing the salt content of 110 medium they could improve the recovery of heat shocked cells and also that when the organisms were incubated in milk for 48 h after heat shocking they recovered their ability to grow on 110 medium of normal salt strength.…”

Bacteriology. The survival of pathogens in cheese and milk powder

“…While most experimental work and surveys of pathogenic staphylococci in cheese have been carried out for Cheddar and Colby, other types have been investigated and the presence of pathogenic staphylococci in them has been reported (Legler, Burkhardt & Wendrich, 1957;Mickelsen, Foltz, Martin & Hunter, 1963). Thatcher et al (1959) examined a number of cheeses of different types imported into Canada.…”

“…Most of them were made from pasteurized milk and no staphylococci were found. Mickelsen, Foltz, Martin & Hunter (1961) surveyed the incidence of pathogenic staphylococci in many varieties of cheese available in the United States and found that 7-2 % contained coagulase-positive staphylococci. They reported a relationship between the presence of coliforms and Staphylococcus aureus in cheese.…”

“…Baird-Parker & Davenport (1965) found that media such as S110 medium and phenolphthalein phosphate agar (Barber & Kuper, 1951), which are poor for the isolation of Staph. aureus cells that have been subjected to heat or drying (Busta & Jezeski, 1961;Sharpe et al 1962;Mickelsen et al 1963;Baird-Parker & Davenport, 1965), can beimprovedby the addition of pyruvate. They suggest that blood and pyruvate have in common the ability to break down hydrogen peroxide, which may account for the fact that media containing these substances are best for the recovery of air-dried, freeze-dried and heatshocked cells of Staph.…”

Ερευνες Πανω Στην Κρυοβιολογια Του Staphylococcus Aureus.

“…σε χαμηλές θερμοκρασίες (Gaughran, 1947α;Allen, 1953;Farrel and Rose, 1967α;1967β), 5. διαταραχές της πρόσ ληψης διαλυμένων ουσιών, πού οφείλονται σέ αλλοίωση ή αδρανοποίηση του συστήματος των περμεασών (Farrel and Rose, 1967β;Brandts, 1967), σέ μεταβολές της μοριακής δο μή^ της κυτταροπλασματικης μεμβράνης (Farrell and Rose, 1967α;1967β;Rose, 1968 (Kates, 1964;Farrell andRose, 1967α, 1967β (Τζαννετης, 1973' Tzannetis, andPapavassiliou, 1975) καί στους 5 (Jackson, 1974 (Haines, 1938;Hartseil, 1949Hartseil, , 1951Major et al 1955;'Αλμπάλας, 1971;Τζαννετής, 1973;Jackson, 1974;Tzannetis and Papavasiliou, 1975) (Jackson, 1974;Tzannetis and Papavassiliou, 1975) καί σέ άλλα βακτηριακά κύτταρα (Sherman and Cameron, 1934;Meynell, 1958, Gorril andMcNeil, 1960 (Straka and Stokes, 1959;Patterson and Jackson, 1979aMcLeod et al, 1966;Jackson, 1974). ή ύποθανάτια θέρμανση τους (Busta and Jezeski, 1963;Mickelsen et al, 1963 Generally, an early, regular and progressively accelerated death rate was observed. However, at temperatures 2 and 4°C and at -4°C at pH 5.5, 6.2 and 8.6 respectively death rate was irregular with accelerations, retardations and stationary phases.…”