TYPES AND POPULATIONS OF MICROORGANISMS IN THE AIR OF FLUID MILK PLANTS

1970 ◽  
Vol 33 (1) ◽  
pp. 19-21 ◽  
Author(s):  
R. Y. Cannon
Keyword(s):  
Microbial Populations ◽  
Gram Negative ◽  
Milk Processing ◽  
Apparent Relationship ◽  
Keeping Quality ◽  
Particle Counts ◽  
Fluid Milk

Airborne viable particle counts in the milk processing areas of 10 dairy plants averaged 14 molds and 32 non-molds/10 liters. The bacteria isolated were primarily micrococci, Gram-negative rods (excluding coliform), bacilli, and coryne-bacteria. Twenty-five per cent of the isolates grew at 10 C in 5 days. These were principally bacilli and Gram-negative rods (excluding coliform). There was no apparent relationship between airborne microbial populations and keeping quality of the packaged milk.

Comparison between the EC plate count test at 21 °C and an accelerated plate count method for assessing the keeping quality of pasteurized milk

1992 ◽  
Vol 59 (3) ◽  
pp. 431-436 ◽  
Author(s):  
Sarah A. Langford ◽  
Rohan G. Kroll
Keyword(s):  
Plate Count ◽  
Gram Negative ◽  
Rapid Methods ◽  
Pasteurized Milk ◽  
Psychrotrophic Bacteria ◽  
Commercial Interest ◽  
Count Method ◽  
Keeping Quality ◽  
Plate Count Method

The keeping quality of properly refrigerated pasteurized milk and cream is primarily determined by post-pasteurization contamination by Gram-negative psychrotrophic bacteria (Phillips et al. 1981; Schröder et al. 1982). Reliable and rapid methods of assessing the levels of contamination by these organisms are therefore of commercial interest.

Effect of pasteurization temperature on the keeping quality of whole milk

1984 ◽  
Vol 51 (4) ◽  
pp. 569-578 ◽  
Author(s):  
Monika J. A. Schröder ◽  
Michael A. Bland
Keyword(s):  
Single Strain ◽  
Gram Negative ◽  
Whole Milk ◽  
Keeping Quality ◽  
C 78

SummaryThe keeping quality (KQ) of whole milks pasteurized at 72 °C, 78 °C or 83 °C for 20 s and stored at 12 or 7 °C was examined by assessment of the naturally contaminating thermoduric microflora and of the numbers of Gram-negative rods, a single strain of the latter being introduced deliberately by post pasteurization inoculation. A pasteurization temperature of 83 °C reduced the KQ at 7 °C by about 15% compared with pasteurization at 72 °C or 78 °C, with a 2 d loss in the absence, and aid loss in the presence, of the post pasteurization contamination. The KQ of milks stored at 12 °C was not significantly affected by the pasteurization temperature. Milks pasteurized at 78 °C tended to have a slightly better KQ than those pasteurized at 72 °C, especially at 7 °C. However, pasteurization at both 78 °C and 83 °C caused a reduction in cream rising and considerably increased the risk of cream plugging.

A survey of the microflora of raw and pasteurized milk and the sources of contamination in a milk processing plant in Addis Ababa, Ethiopia

1990 ◽  
Vol 57 (2) ◽  
pp. 233-238 ◽  
Author(s):  
Tadesse Mahari ◽  
Berhanu A. Gashe
Keyword(s):  
Addis Ababa ◽  
Raw Milk ◽  
Processing Plant ◽  
Pasteurized Milk ◽  
Milk Processing ◽  
Milk Samples ◽  
Keeping Quality ◽  
Thermophilic Organisms ◽  
Sources Of Contamination

SummaryThe microorganisms present in raw and pasteurized milk and the sources of contamination in the milk after it had arrived at the processing plant in Addis Ababa were studied. The lowest count registered for raw milk samples was 4 × 107cfu/ml while the highest was 1 × 109cfu/ml. Pasteurized milk had mesophilic aerobic counts of 7 × 105cfu/ml as it left the pasteurizing unit, but the population increased 2- to 4-fold as a result of subsequent contamination. Of the total counts in raw milk, psychrophilic, thermoduric and thermophilic organisms made up 98·l, 1·4 and 0·5% respectively. In pasteurized milk, the amounts were 53·0, 39·5 and 7·5% respectively. Samples of milk pasteurized in the laboratory contained only 74·5% thermoduric and 25·5% thermophilic organisms. The isolates mostly belonged to the generaBacillus, Streptococcus, Lactobacillus, Arthrobacter, Alcaligenes, AeromonasandPseudomonas. Cocci were more predominant than rod-shaped bacteria. Of the rod-shaped bacteria, 73% were Gram-negative. The utensils holding the raw and pasteurized milk and the plastic sheets used for bagging the pasteurized milk contributed unusually high numbers of bacteria which were either thermoduric or thermophilic. More isolates were obtained from the pasteurized than the raw milk. The keeping quality of the pasteurized milk was found to be much lower than that of the laboratory-pasteurized milk.

571. The effect of menadione (2-methyl-l: 4-naphthoquinone) on the keeping quality of milk

1955 ◽  
Vol 22 (1) ◽  
pp. 48-59 ◽  
Author(s):  
Constance Higginbottom
Keyword(s):  
Milk Yield ◽  
Bacterial Flora ◽  
Titratable Acidity ◽  
Well Being ◽  
Coliform Bacteria ◽  
Gram Negative ◽  
Large Numbers ◽  
Keeping Quality ◽  
Quality Of Milk

1. The addition of 1 µg. menadione/ml. to milk had no effect on the souring of the milk at 37° C. With higher concentrations of menadione the effect on the keeping quality at 37° C. varied with different milks. In some milks the clot-on-boiling stage was delayed by 1 hr. with 10 µg. menadione and by 2 to over 5 hr. with different milks containing 100 µg. menadione per ml. Some milks, however, showed no alteration in the keeping quality at 37° C. with as much as 1000 µg. menadione/ml.2. The response of individual milks to the presence of menadione appeared to be related largely to the bacterial flora of the milk, The relative insensitivity of Gram negative rods, including coliform bacteria and of enterococci, to menadione was confirmed. Milks containing large numbers of coliform bacteria showed the least and those free of such bacteria the greatest response to menadione.3. Menadione fed to milking cows at the rate of 100 mg·/day for a period of 3 weeks had no effect on the keeping quality of the milk when it was held at 37, 22 or 15·5° C. The time of incubation required for the milk to attain a titratable acidity equivalent to 2 ml. N/9-NaOH, to become unstable to 68 % alcohol or to boiling showed no difference between the milk from the cows given menadione and that from the control cows.4. The menadione had no demonstrable effect on the appetite or the well-being of the cows nor on their milk yield.5. When as much as 100 μg. menadione was given per cow per day, no menadione was detected in the milk under conditions suitable for the detection of 1 μg. menadione/ml.milk.

Relation of Bacterial Counts to Quality of Cod Fillets

1948 ◽  
Vol 7b (6) ◽  
pp. 378-388 ◽  
Author(s):  
C. H. Castell ◽  
G. W. Anderson ◽  
Hilliard Pivnick
Keyword(s):  
No Value ◽  
Cold Storage ◽  
Low Temperatures ◽  
Close Correlation ◽  
General Tendency ◽  
Gram Negative ◽  
Bacterial Counts ◽  
Keeping Quality ◽  
Gram Negative Organisms

Bacterial counts are valueless as a measure of the degree of spoilage in fresh fillets.There is a very close correlation between the number of psychrophilic gram-negative organisms on fillets and their keeping time in cold storage. This correlation degenerates into a 'general tendency' which cannot always be applied to individual samples, if the counts used include all the organisms growing on plates incubated at 25 °C. Counts made on plates incubated at 37 °C are of no value for estimating the keeping quality of fillets stored at low temperatures.

Comparison of Code Date Reliability for Freshly Bottled Whole, Lowfat and Nonfat Fluid Milk

1980 ◽  
Vol 43 (3) ◽  
pp. 175-177 ◽  
Author(s):  
LESTER HANKIN ◽  
GEORGE R. STEPHENS ◽  
WALTER F. DILLMAN
Keyword(s):  
Flavor Score ◽  
Raw Milk ◽  
Milk Samples ◽  
C Storage ◽  
Whole Milk ◽  
Keeping Quality ◽  
Flavor Deterioration ◽  
Storage Temperatures ◽  
Fluid Milk

Whole, lowfat, and nonfat fluid milk samples were collected from dairy plants on the day of bottling and each set of the three types of milk was processed from the same raw milk supply. Bacterial analyses for total aerobic count and for specific degradative types were made immediately after collection. Samples were also stored at 1.7, 5.6 and 10.0 C to test for flavor deterioration. Total count of aerobic bacteria and of specific degradative types did not differ significantly among the three types of milk. Organoleptic analysis was made periodically to determine milk quality (flavor score) and defect (flavor). At any of the storage temperatures the keeping quality (days required from bottling to reach a flavor score of < 36) was unrelated to the length of time between bottling and last day of sale (code date) assigned by the processor. At 5.6- and 10.0-C storage, more whole milk samples were criticized for more serious flavor defects (e.g. putrid) than for the less serious ones (e.g. lacking freshness) found in the lower fat milks. Keeping quality of all three types of milks at 1.7- and 5.6-C storage could be predicted from keeping quality determined at 10.0 C with equations previously developed for whole milk.

A Survey of Four Fluid Milk Processing Plants for Airborne Contamination Using Various Sampling Methods

1992 ◽  
Vol 55 (1) ◽  
pp. 38-42 ◽  
Author(s):  
TYH-JENQ REN ◽  
JOSEPH F. FRANK
Keyword(s):  
Sampling Methods ◽  
Raw Milk ◽  
Particle Counter ◽  
Milk Processing ◽  
Airborne Contamination ◽  
Processing Plants ◽  
Particle Counts ◽  
Milk Storage ◽  
Andersen Sampler ◽  
Fluid Milk

Air in four commercial fluid milk plants was sampled for microbiological and nonmicrobiological particles over a 4-month period. An Andersen two-stage and Ross-Microban sieve samplers, a Biotest RCS sampler, and a Met-one laser particle counter were used to sample air. Air was sampled two to three times per day in raw milk storage, processing, and filling areas. Viable particle counts per 100 L air obtained with the Andersen sampler were 2.03 ± 0.41 (log10 Mean ± SD), 2.26 ± 0.57, and 2.41 ± 0.70 in raw milk storage, processing, and filling areas, respectively. These levels were significantly (p<0.05) greater than those obtained using the RCS and Ross-Microban samplers. Overall correlations of the Ross-Microban and RCS samplers with the Andersen sampler were r2 = 0.71 and 0.62, respectively. Correlations between Andersen sampler results and number of total particles greater than 0.5 μm were r2 = 0.36 in raw milk storage, 0.15 in the processing area, and 0.18 in the filling area.

The fate of formaldehyde in sugar manufacture and in products

2015 ◽  
pp. 692-696
Author(s):  
Remi Aubry ◽  
Laurence Gasnot
Keyword(s):  
Sugar Industry ◽  
Common Knowledge ◽  
Microbial Populations ◽  
Optimal Dosage ◽  
Consumer Health ◽  
Microbiological Activity ◽  
Specific Process ◽  
Beet Sugar ◽  
Series Of Experiments

A study was carried out in six beet sugar factories in France during the 2012/13 sugar campaign. The objective was to assess the optimal dosage of formaldehyde solutions at specific process stages and in different existing factory set-ups in order to obtain the desired effect on microbial populations, without interference with the quality of the products. In addition harmlessness regarding consumer health was to be demonstrated. A series of experiments was conducted resulting in new data allowing refreshment of common knowledge and references existing regarding the use of formaldehyde solutions in the sugar industry. The effectiveness and convenience for controlling microbiological activity in beet sugar manufacture was assessed. Formaldehyde reduces sugar losses and protects in-process products without harming their further use, such as for ethanol production.

Quality Improvement of the DNA extracted by boiling method in Gram negative bacteria

2017 ◽  
Vol 6 (04) ◽  
pp. 5347 ◽  
Author(s):  
Omar B. Ahmed* ◽  
Anas S. Dablool
Keyword(s):  
Dna Extraction ◽  
Control Method ◽  
Extraction Procedure ◽  
Cost Effective ◽  
High Yield ◽  
Gram Negative Bacteria ◽  
Bacterial Dna ◽  
Gram Negative ◽  
E Coli

Several methods of Deoxyribonucleic acid (DNA) extraction have been applied to extract bacterial DNA. The amount and the quality of the DNA obtained for each one of those methods are variable. The study aimed to evaluate bacterial DNA extraction using conventional boiling method followed by alcohol precipitation. DNA extraction from Gram negative bacilli was extracted and precipitated using boiling method with further precipitation by ethanol. The extraction procedure performed using the boiling method resulted in high DNA yields for both E. coli and K. pneumoniae bacteria in (199.7 and 285.7μg/ml, respectively) which was close to control method (229.3 and 440.3μg/ml). It was concluded that after alcohol precipitation boiling procedure was easy, cost-effective, and applicable for high-yield quality of DNA in Gram-negative bacteria.

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