Search PubMed⌕ Search

Biomedical subjects

J Borneff

Publications and source records attributed to J Borneff.

At least 37 records · Page 2Linked to original sources
PubMed1975

Investigations on the efficacy of surface disinfection and surface cleaning procedures. 3. Evaluation of the results of in-use and laboratory tests.

3 disinfectants and 3 disinfectant cleaning agents were subjected to comparative tests as to their germicidal activity. These were (a) laboratory tests with germ carriers and (b) in-use tests with Sarcina-contaminated floor surfaces in a medical institute. The results, details of which are given in the two preceding publications, were assessed under the following angles: Validity of the test methods, requisite changes of the test procedures and practical usefulness of the different types of preparations. This assessment led to the following conclusions: New preparations should first be tested for their bacteriostatic activity according to DGHM and the neutralising agents should be determined. The suspensions tests - which remain to be standardised- provide information on the sensitivity to protein, hard water and detergent surface active substances. The germ carrier tests with operating-theatre tiles, carried out with at least 5 test germs, must result in a germ count reduction of more than 5 powers of ten (regardless of the elimination rate due to drying). In-use tests should stand at the end of the test series. Regular epidemiological studies are hardly feasible in all individual cases. An assessment on the basis of the behaviour of normal bacterial spores is likewise impracticable. The use of test germs cannot be dispensed with. Sarcina is a suitable species provided germ-carrier tests have first been carried out and have shown that Staphylococci, Klebsiellae and other high-risk germs are more sensitive to the preparation than Sarcina lutea. In the in-use tests, we consider a reduction by 2 to 3 powers of ten to be sufficient.

Cell Count↗
PubMed1975

[Critical assessment of methods for testing chemical disinfectants and disinfection procedures (author's transl)].

Since the earliest days of disinfectant testing two different methods have to be distinguished: one group simulating practical circumstances the other one allowing the determination of germ reduction, disregarding any practical conditions. At present the assessment of disinfectant substances is carried out according to the results of several methods, done in different countries. Usually standardised suspension-tests with no correspondance to-in-use conditions are done. These are for example the determination of the Rideal-Walker and the Chick Martin coefficient and the capacity test by Kelsey and Sykes as well. Results obtained by the use-dilution method (A.O.A.C.) are also just of theoretical value. The British Standard-Test 3286:1960 and the suspension-test of the Committee on Phytopharmacy (Netherlands), to be preferred in order to state germ reductions, do not imitate particulars of practice either. After establishing recommendations for the various disinfectant procedures, the unification of the test methods on international level should be the next aim. Besides evaluation of disinfectant substances (as it is done by suspension-tests) the testing of disinfectant procedures under conditions, copying those of real life ought to be required. The results of such in-use model tests should answer all the questions arising, for instance, what the concentrations or the exposure-time should be. We would plead in favour of testing disinfectant substances and procedures in two steps - preliminary testing and main tests under in-use conditions for each new preparation. The base for all these tests is the selection of a suitable inactivator.

Disinfectants↗
PubMed1975

[Studies on the reduction of microorganisms in icecream in production and storage (author's transl)].

Experimental analyses referred to in this publication were to clarify two important hygienic-bacteriological issues: 1. Which is the capacity of survival owned by microorganisms in icecream in correspondence to temperature and storing time, and what significance have the results in regard to the length of intervals between the taking of samples of icecream and their examination. 2. Which nutritient media are suitable for a routine diagnostic of coliforms? Analyses were being made with an artificially contaminated, industrially produced icecream (Vanilla icecream with 10 per cent milk fat and strawberry icecream with 6,6 per cent milk fat and 21 per cent strawberries). Inoculations were only done with strains of bacteria isolated from icecream. We employed one strain of Escherichia coli, Staphyloccus aureus, Pseudomonas aeruginosa and three strains of Coliforms for each inoculation. Contaminated samples were stored in deep-freeze units at three different temperatures(-28, -18, -8 degrees C). In the beginning inspections in regard to microbial content were performed in daily intervals, but intervals grew longer in the course of time. At the utmost samples were under observation for 140 days. For quantitative measurement of Coli and Coliform microorganisms five different culture media were used (Endoagar, Hexachlorophene Endoagar, Desoxycholatcitrat Agar, Violet Red Bile Agar and Brilliant Green Broth). Generally results showed, that icecream, if being stored, looses approximately one to two quarters of the bacteria within hours after production, the third dies within days and the rest after weeks and months. Within the given period of observation sterility can only be reached with rather sour kinds of icecream. E. coli proved to be moderately resistant, Coliforms were somewhat more sensitive. Staphylococci showed in the beginning a lower drop, but in the course of time similar rates as Coli and Coliforms. Only with Pseudomonas inactivation was distinctly more rapid. Differences concerning kinds of icecream and temperatures were not to be secured statistically. Examination of cultur media for the demonstration of E. coli and Coliforms resulted that Hexachlorophene Endoagar is the best one. It is recommended, to take icecream samples at the earliest at the time the icecream is to be sold. Bacteriological cultures should be prepared within 14 days. Controls are to be made at the earliest possible date, but not later that two weeks after the official analysis. Findings with a lower count reached at a later date do not contradict an earlier result of two to five times higher rates. Reliable constants for the retrospect establishment of balances of microbial content were not to be found.

Analysis of Variance↗
PubMed1975

[Testing the sterilisation effect of autoclaves by means of biological indicators (author's transl)].

Because of the great number of failures with sterilization-programs it seems to be necessary to check up the effect of sterilization not only by the annual official tests but also continuously with biological indicators. Marketable indicators have not to be tested necessarily at present. Therefore six different types of indicators were examined experimentally and under practice-conditions. As to be seen in table 1 samples of the same charge didn't show great differences, in spite of this germ-counts of several charges differed considerably. Reductions of germ-counts after sterilization in the autoclave at 123,5 degrees C (fig. 1) and at 134 degrees C (fig 2), as well as with hot air at 120-125 degrees C (fig 3) and 133-138 degrees C (fig 4) demonstrate the heat-resistance. The individual biological indicators differ in killing-time and times of survival (table 2). Our tests demonstrate that only single biological indicators (table 4) will grant satisfying results in continuous checking of sterilization process.

Bacillus subtilis↗