The alcohol test applied to sterilized milk

1960 ◽  
Vol 27 (2) ◽  
pp. 259-265
Author(s):  
Constance Higginbottom ◽  
Margaret M. Taylor
Keyword(s):  
Bacillus Subtilis ◽  
Population Density ◽  
Stationary Phase ◽  
Incubation Period ◽  
Bacterial Count ◽  
Keeping Quality ◽  
Lower Maximum ◽  
Sterilized Milk ◽  
Maximum Population Density

SummaryA positive 80% alcohol test was not obtained in sterilized milks containing fewer than 105 bacteria/ml with Bacillus subtilis, B. licheniformis and B. cereus, and usually did not occur until the stationary phase of growth had been maintained for some days. A positive alcohol test with less than 105 bacteria/ml was associated with the lower maximum population density of B. brevis and B. circulans 152.The alcohol test after 24 h at 37°C was found unreliable as an indicator of the keeping quality of sterilized milk at 22°C. The possibility of using the alcohol test after 3 days at 37°C or a bacterial count after the same incubation period is discussed briefly.

scholarly journals Keeping Quality of Milk and the Age on Testing for Total Bacterial Count

1931 ◽  
Vol 31 (3) ◽  
pp. 373-374 ◽  
Author(s):  
H. Barkworth
Keyword(s):  
Bacterial Count ◽  
Total Bacterial Count ◽  
Keeping Quality ◽  
Quality Of Milk

During the period 1923–29 inclusive nearly six thousand samples of milk were tested at Wye for both total bacterial count and also keeping quality. An examination of the results shows that on the average the afternoon milks showed nine hours less keeping quality than morning milks of the same total bacterial count, see Table I. The age of the milk on testing for total bacterial count (reckoned from the time of milking) is 27–29 hours for morning milks and 20–24 hours for afternoon milks.

SOME OBSERVATIONS ON THE BACTERIOLOGICAL KEEPING QUALITY OF MILK PROCESSED BY HIGH TEMPERATURES WITH A 0.6 SECOND HOLDING TIME1 2

1963 ◽  
Vol 26 (10) ◽  
pp. 332-336 ◽  
Author(s):  
D. A. Evans ◽  
Eleanor L. Lachman ◽  
Warren Litsky
Keyword(s):  
Heat Treatment ◽  
Raw Milk ◽  
Plate Heat Exchanger ◽  
Plate Heat ◽  
Milk Samples ◽  
Whole Milk ◽  
Keeping Quality ◽  
Quality Of Milk ◽  
Sterilized Milk

Summary Raw milk was processed through a commercial sized plate heat exchanger at temperatures of 160 F through 260 F with a 0.6 sec hold. Milk samples were collected at increments of 10 F during processing and analyzed for psychrophilic, mesophilic and thermophilic counts initially and at weekly intervals thereafter. All samples were held at 40 F after processing. Results indicated that temperatures of processing at 160 F and 170 F were not sufficient to impart acceptable keeping qualities to whole milk held at 40 F for a period of one week. By comparison, processing temperatures of 180 F through 210 F with 0.6 sec hold appeared to impart to whole milk keeping qualities which were approximately comparable to those observed in milk pasteurized according to present standards. When heat treatment in the range of 220 F through 260 F were used, it was indicated that bacteriological keeping quality of the milk was improved to an extent far beyond that experienced with present day commercial pasteurization. There appeared to be somewhat of a tendency for higher count raw milk related to the level of population in the processed product although the magnitude of this relationship was not clearly defined in all cases. It was evident that this process did not produce “commercially sterilized” milk at the processing temperatures and holding time used.

Effect of oxygen on the keeping quality of milk: II. Effect of available oxygen on bacterial spoilage and oxygen uptake

1982 ◽  
Vol 49 (3) ◽  
pp. 425-437 ◽  
Author(s):  
Monika J. A. Schröder
Keyword(s):  
Oxygen Uptake ◽  
Shelf Life ◽  
Bacterial Growth ◽  
Bacterial Count ◽  
Bacterial Activity ◽  
Pasteurized Milk ◽  
Keeping Quality ◽  
Quality Of Milk ◽  
Effect Of Oxygen

SUMMARYThe effect of limiting the amount of O2 present in commercially pasteurized milk on bacterial growth and on the keeping quality of the milk was investigated. No increase in bacterial count of laboratory pasteurized milk during storage for 9 d at 5 °C was observed and O2 consumption due to bacterial activity was low. In commercial pasteurized milk containing post-pasteurization contamination (PPC) growth of strict aerobes was encouraged by high O2 content while that of coliforms was less dependent on O2 level. The amounts of headspace (HS) O2 consumed in milk with PPC growth were large. Reducing the dissolved O2 content of commercial pasteurized milk stored in O2-impermeable containers without HS had little effect on bacterial activity and shelf-life.

Usefulness of the Benzalkon-Crystal Violet-ATP Method for Predicting the Keeping Quality of Pasteurized Milk

1982 ◽  
Vol 45 (10) ◽  
pp. 928-931 ◽  
Author(s):  
G. M. WAES ◽  
R. G. BOSSUYT
Keyword(s):  
Shelf Life ◽  
Crystal Violet ◽  
Quantitative Estimation ◽  
Bacterial Count ◽  
Total Bacterial Count ◽  
Life Test ◽  
Pasteurized Milk ◽  
Keeping Quality ◽  
Factory Laboratory

Using the benzalkon-crystal violet-ATP method (BC-ATP method), post-pasteurization contamination of pasteurized milk caused by gram-negative bacteria can be determined within 24 h. This study determined to what extent the keeping quality of pasteurized milk can be predicted by applying this BC-ATP method. Results obtained with the BC-ATP method for 100 samples of pasteurized milk were compared with those recorded in the shelf-life test (total bacterial count after 10 d of storage of samples at 7°C; standard: 106 bacteria per ml) and the Moseley test (bacterial count after 5 d of storage at 7°C; standard: 105 bacteria per ml). Using the shelf life test and the Moseley test, 14 and 8% of the results, respectively, did not correspond with those obtained with the BC-ATP method. From the results obtained, it was obvious that the greater the post-pasteurization contamination of the pasteurized milk, the lesser is the keeping quality. A quantitative estimation of the degree of post-pasteurization contamination can be obtained satisfactorily by applying the BC-ATP method to 1000-, 100-, 10- and 1-ml portions. The Moseley test takes too much time to achieve a good coordination between the factory laboratory and the pasteurization and filling sections of the dairy factory. By substituting the BC-ATP method applied to 100-ml portions of pasteurized milk for the Moseley test (5 d at 7°C; standard: 100,000 bacteria per ml) almost the same information is obtained within 24 h.

PSYCHROPHILIC BACTERIA AND KEEPING QUALITY OF PASTEURIZED DAIRY PRODUCTSl1,2

1964 ◽  
Vol 27 (3) ◽  
pp. 69-75 ◽  
Author(s):  
P. R. Elliker ◽  
E. L. Sing ◽  
L. J. Christensen ◽  
W. E. Sandine
Keyword(s):  
Shelf Life ◽  
Bacterial Count ◽  
Economic Advantage ◽  
Sampling Techniques ◽  
Careful Study ◽  
Quality Test ◽  
Psychrophilic Bacteria ◽  
Keeping Quality ◽  
Plant Equipment

Summary A study was made showing relationship between post-pasteurization contamination of milk and cream and increase in bacterial count of bottled and paper carton products during storage at 45 F for 5 days. A survey indicated extensive post-pasteurization contamination in plants not employing this type of keeping quality test. The 5-day at 45 F test was more sensitive than the coliform test in detecting post pasteurization contamination. Excessive numbers of thermoduric bacteria in the raw supply also were detected by this method when plant equipment was properly cleaned and sanitized. Special in-line sampling techniques were developed to determine source of contamination. One procedure employed sterile disposable hypodermic syringes inserted through rubber stoppered nipples welded into lines at different locations in the system. Another technique involved removal of samples by insertion of sterile disposable hypodermic syringes through rubber or neoprene gaskets between joints in different locations in the plant. Bottle and paper carton filler equipment offered special cleaning and sanitizing problems and suggestions were made on steps to minimize contamination from these sources. Application of the 5-day at 45 F keeping quality test followed by careful study of contamination sources has greatly improved shelf life of pasteurized fluid milk and cream and has represented a real economic advantage to plants adopting the program.

scholarly journals Effect of BioPlus YC Probiotic Supplementation on Gut Microbiota, Production Performance, Carcass and Meat Quality of Pigs

Animals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1581
Author(s):  
Artur Rybarczyk ◽  
Elżbieta Bogusławska-Wąs ◽  
Alicja Dłubała
Keyword(s):  
Bacillus Subtilis ◽  
Meat Quality ◽  
Bacillus Licheniformis ◽  
Average Daily Gain ◽  
Production Performance ◽  
Probiotic Bacteria ◽  
Control Group ◽  
Production Traits ◽  
Feed Conversion

The objective of the study was to determine the effects of probiotic bacteria Bacillus licheniformis and Bacillus subtilis on microbiological properties of feed mixtures and on the digestive tract content as applicable to production traits and carcass characteristics of fatteners. The experiment was performed on 83,838 fatteners from four successive (insertions) productions in two groups. From the seventy eighth day of age till marketing to the slaughter plant, the pigs were supplied with BioPlus YC probiotic (Chr. Hansen) in the amount of 400 g/t. The preparation contained a complex of probiotic bacteria Bacillus licheniformis DSM 5749, and Bacillus subtilis DSM 5750 spores in a 1:1 ratio. From the fourth insertion, after reaching a body weight of approximately 112 kg, 60 fatteners were selected from each group to measure carcass quality and half of them for meat quality evaluation. Moreover, microbiological analyses in feed and colon were performed. The study showed that BioPlus YC probiotics supplementation resulted in a significantly higher count of B. subtilis and B. licheniformis in the feed, a higher count of B. subtilis, B. licheniformis and LAB, as well as a lower count of Enterobacteriaceae, Enterococcus, Clostridium and Bacillus sp. in the mucosa and in the colorectal content of the test pigs. Our work has shown that supplementation with the BioPlus YC probiotic had a positive effect on the production traits of pigs mainly by reducing mortality (2.83%, p = 0.010), lowering feed conversion ratio—FCR (2.59 kg/kg, p = 0.013), better average daily gain—ADG (0.95 kg/day, p = 0.002) and shorter fattening period (77.25 days, p = 0.019) when compared to the control group (4.19%; 2.79 kg/kg; 0.89 kg/day; 92.8 days, respectively). The addition of the specific Bacillus bacteria did not influence carcass and meat characteristics of the test fatteners.

Keeping Quality of Pacific Coast Dogfish

1959 ◽  
Vol 16 (6) ◽  
pp. 791-794 ◽  
Author(s):  
R. H. Moyer ◽  
B. A. Southcott ◽  
E. G. Baker ◽  
H. L. A. Tarr
Keyword(s):  
Pacific Coast ◽  
Sea Water ◽  
Total Volatile ◽  
Bacterial Counts ◽  
Ph Values ◽  
Appreciable Increase ◽  
Muscle Ph ◽  
Keeping Quality ◽  
Viable Bacteria

Pacific coast dogfish (Squalus suckleyi) were held 21 days in ice and in refrigerated sea water with and without added chlortetracycline, viable bacterial counts and volatile bases being determined periodically. Viable bacteria increased sharply after about 14 days but the muscle pH values showed little or no increase. No appreciable increase in the total volatile base or trimethylamine content of the muscle was noted until the fish were stored for more than 2 weeks, and then the increases observed were comparatively small.

scholarly journals Non-B DNA-Forming Motifs Promote Mfd-Dependent Stationary-Phase Mutagenesis in Bacillus subtilis

2021 ◽  
Vol 9 (6) ◽  
pp. 1284
Author(s):  
Tatiana Ermi ◽  
Carmen Vallin ◽  
Ana Gabriela Regalado García ◽  
Moises Bravo ◽  
Ismaray Fernandez Cordero ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Stationary Phase ◽  
Genome Instability ◽  
Mutagenic Effect ◽  
Genetic Changes ◽  
Dna Structures ◽  
Coding Regions ◽  
G4 Dna ◽  
Stressed Cells ◽  
Growing Conditions

Transcription-induced mutagenic mechanisms limit genetic changes to times when expression happens and to coding DNA. It has been hypothesized that intrinsic sequences that have the potential to form alternate DNA structures, such as non-B DNA structures, influence these mechanisms. Non-B DNA structures are promoted by transcription and induce genome instability in eukaryotic cells, but their impact in bacterial genomes is less known. Here, we investigated if G4 DNA- and hairpin-forming motifs influence stationary-phase mutagenesis in Bacillus subtilis. We developed a system to measure the influence of non-B DNA on B. subtilis stationary-phase mutagenesis by deleting the wild-type argF at its chromosomal position and introducing IPTG-inducible argF alleles differing in their ability to form hairpin and G4 DNA structures into an ectopic locus. Using this system, we found that sequences predicted to form non-B DNA structures promoted mutagenesis in B. subtilis stationary-phase cells; such a response did not occur in growing conditions. We also found that the transcription-coupled repair factor Mfd promoted mutagenesis at these predicted structures. In summary, we showed that non-B DNA-forming motifs promote genetic instability, particularly in coding regions in stressed cells; therefore, non-B DNA structures may have a spatial and temporal mutagenic effect in bacteria. This study provides insights into mechanisms that prevent or promote mutagenesis and advances our understanding of processes underlying bacterial evolution.

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