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Biomedical subjects

G Mocquot

Publications and source records attributed to G Mocquot.

At least 19 recordsLinked to original sources
PubMed1977

[Destruction of Microbacterium lacticum, Escherichia coli and Staphylococcus aureus in milk by sprayedrying. II. Effect of drying conditions].

Bacterial death during spray drying of skim milk is essentially related to the outlet temperature of the spray drier and the type of bacteria. Under industrial spray drying conditions, survival rates of Microbacterium lacticum, Staphylococcus aureus and Escherichia coli were 50, 2, and 0.002%, respectively. These rates may vary by a 10(4) factor for outlet temperatures between 65 and 105 degrees C. No simple mathematical equation could be derived to describe the relation between bacterial death rates and outlet temperature. Our results suggest that bacterial death is due in most cases to a heating effect during the last stages of drying when the temperature of the powder particle approaches that of the air at the outlet.

Actinomycetales↗
PubMed1977

[Destruction of Microbacterium lacticum, Escherichia coli and Staphylococcus aureus in milk by spray-drying. I. Selective count of surviving bacteria].

In this paper a method which allows the measure of microbial death rate during spray-drying by means of a streptomycin-resistant mutant that can be grown on a streptomycin-containing agar is described. Plate counts of Microbacterium lacticum, Escherichia coli, and Staphylococcus aureus recovered from skim milk powders were done on plate count agar in the presence and absence of streptomycin and on various selective media. The powders were produced from evaporated milk previously inoculated with those organisms. Our results showed that the proposed method allows the recovery of 78% of M. lacticum, 61% of E. coli, and 100% of S. aureus that survived spray-drying. Recoveries of surviving E. coli on violet bile agar and brilliant green bile 2% were 34% and 29% respectively. Baird-Parker and mannitol salt agar media allow the recovery of all surviving S. aureus, thus showing that S. aureus cells did not lose their ability to grow in media containig 7.5% NaCl. Our results show that physiological injury of the cells during spray-drying differs from injury due to heating only.

Actinomycetales↗
PubMed1976

[An agar medium for direct enumeration of Staphylococcus aureus: pork plasma medium for S. aureus (PPSA)].

A selective agar medium (pork plasma medium for S. aureus (PPSA)) enables the direct enumeration of coagulase-positive staphylococci. This medium is based on the Baird-Parker agar without egg yolk and is supplemented with pig plasma. Colonies of Staphylococcus aureus are surrounded by a halo of precipitated fibrin. When foods such as dairy products contain large numbers of egg yolk-negative strains of S. aureus, the PPSA agar has the advantage over egg yolk containing media such as Baird-Parker agar that fewer suspect colonies have to be confirmed.

Agar↗
PubMed1968

Agar medium for the selective enumeration of coagulase-positive Staphylococcus from the rat alimentary tract.

A selective agar medium (medium J(1)) is proposed for the quantitative enumeration of egg yolk-positive (EYP) and egg yolk-negative (EYN) Staphylococcus pyogenes from the digestive tract and feces of the rat. This medium, buffered at pH 5.0, is composed of acid casein hydrolysate and yeast extract with 7.5% sodium chloride, 1.6% sodium pyruvate, 0.0008% 2,3,5-triphenyltetrazolium chloride (TTC), and 6% egg yolk emulsion. Inoculation is by the pour-plate method and incubation is at 38 C in a water-jacketed incubator for 36 hr. Colonies of S. pyogenes reduce TTC; EYP strains are surrounded by a halo of opacity; and EYN strains may be surrounded by a red halo, but no opacity. Small, white colonies of S. epidermidis may develop, but Micrococcus, and all other groups of Staphylococcus recognized in the rat intestinal flora, are inhibited. Other bacterial genera, notably Bacillus, Corynebacterium, Proteus, and Streptococcus, are also inhibited.

Agar↗