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

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.

1987 ◽  
Vol 50 (8) ◽  
pp. 665-668 ◽  
Author(s):  
F. F. J. NIEUWENHOF ◽  
J. D. HOOLWERF

An improved impedance method is described with a good standard deviation of repeatability (sm = 0.05 log unit) and a fair standard deviation of the estimate of the plate count from the detection time [(sy)x = 0.33 log unit]. Compared with the standard deviation of repeatability of the plate count method (0.07 log unit), the standard deviation of repeatability of the impedance method described is a significant improvement. The impedimetric experiments were done with a Bactometer M123. The detection times as measured by this instrument were compared with the plate counts at 30°C for samples of raw refrigerated farm milk. With this technique a good indication of the microbiological quality of raw milk can be obtained within 15 h.


2019 ◽  
Vol 9 (5) ◽  
pp. 959 ◽  
Author(s):  
Anjum Rashid ◽  
Imran Javed ◽  
Barbara Rasco ◽  
Shyam Sablani ◽  
Muhammad Ayaz ◽  
...  

(1) Background: Multiple attempts have been conducted to correlate milk keeping quality with chemical, physical or bacteriological parameters. These methods only measure the chemical changes in milk produced by bacteria. Headspace solid-phase micro-extraction (HS-SPME) is an economic and recent method used to measure both volatile compounds and microbial load in milk, also allowing to keep the quality of the milk product. (2) Methods: The present study was conducted to identify and measure the off-flavoring volatile compounds through gas chromatography coupled with flame ionization detector (GC-FID) and the microbial load of pasteurized fluid milk stored at different temperatures, as a possible indicator of its keeping quality. (3) Results: The highest results were obtained to acetone, followed by butanone, pentanal and ethanol. These mean values were significantly enhanced from the 0 to 19th day of storage, at 10 °C. At day 19th, the minimum score for aroma, flavor and overall acceptability were also recorded as 4.33 ± 0.17, 4.02 ± 0.06, 4.00 ± 0.04, respectively. Likewise, maximum values for standard plate count (Log10 CFU 15.54 ± 0.40 mL−1) and total psychotroph count (Log10 CFU 11.67 ± 0.30mL−1) were reported at 10 °C and 4 °C. (4) Conclusion: HS-SPME/GC-FID methodology revealed to be very sensitive and capable to be applied in volatile compounds quantification in pasteurized milk produced during the storage period at different temperatures.


2019 ◽  
Vol 1 (1) ◽  
pp. 7-11
Author(s):  
M.Yusri Dadan Nugraha ◽  
Riyanto Riyanto ◽  
Hanifah Mutia Z.N Amrul

The research on bacterial testing on boiled water of boiled mackerel (Rastelliger sp) has been conducted. The study applied treatment of boiled water that is not replaced and is used continuously in several stages. This study aims to determine the effect of boiled water on the quality of fish production, and determine its effect on meat tectrus, gill color, and aromas. The study was conducted with a descriptive qualitative method. Boiled mackerel quality is measured using the total plate count method, which is to count the number of bacterial colonies in the water before boiling and after boiling.


Author(s):  
R. Matura ◽  
V. Bahuguna ◽  
M. Bhandari ◽  
I. Thapa ◽  
S. Jain

Background: Bio-fertilizers are the substances which contain living microorganisms, when applied to soil, seeds and plant root these fertilizers increases soil fertility and promote growth of the plant. Biofertilizers help plants to utilize important mineral resources, phosphorous and nitrogen. Microorganisms like Rhizobacteria, fungi and algae which provide nutrient to the soil and which are produced commercially are known as biofertilizers. The microorganisms which present in biofertilizers are Rhizobium species, Pseudomonas species and Azospirillum species etc. These biofertilizers have potential to replace conventional chemical fertilizers. The quality of biofertilizers is utmost important as they have to be used by farmers and should work well when applied to the soil. It should not form clumps after preparation. In this study, anticaking property provided by tricalcium phosphate (TCP) to individual biofertilizer containing Pseudomonas, Rhizobium and Azospirillum respectively (each separately) was studied. Methods: In our study, we have used serial dilution and direct count method (CFU) for checking viability of live microorganism for 15, 30 and 90 days duration in respective biofertilizers in our laboratory. Different percentage viz 5%, 10%, 15% and 20% of tricalcium phosphate (TCP) was used in addition to aluminium silicate as an inert carrier.Conclusion: Our study has validated that all percentage (5%, 10%, 15% and 20%) of tricalcium phosphate (TCP) is reducing clump formation as compared to control with no TCP added. On the basis of plate count method (CFU result) 10% TCP is found to be optimum to be used as an anticaking agent for biofertilizer containing Pseudomonas, Rhizobium and Azospirillum respectively.


1976 ◽  
Vol 32 (1) ◽  
pp. 21-27 ◽  
Author(s):  
C B Donnelly ◽  
J E Gilchrist ◽  
J T Peeler ◽  
J E Campbell

2008 ◽  
Vol 8 (1) ◽  
pp. 21-24
Author(s):  
Yusdar Zakaria

Chemical, microbiological and organoleptical of yogurt using the different of percentage lactobacillus casei and sugar levelABSTRACT. The objective of this study is to know quality of yogurt with variant of percentage Lactobacillus casei and sugar level. The parameter of this study were the crude protein applying the Kjeldhal method, the crude fat applying the Gerber method, the sum of amount of alive of micro-organism applying the plate count method and the organoleptic applying the square of. The result of this study showed that the different of sugar level is significant (P0.05) on crude protein and crude fat, however the different of percentage L casei not significant (P 0,05) on all parameter. The interaction is only found between two factors on crude fat. The highest of the rate amount of alive microorganism, crude protein and acetic acid are found in yogurt using 10% L. casei and 15% sugar level. From organoleptic test, it’s found that yogurt using 10% L. casei and 15% sugar level is the most prevered kind of yogurt.


1932 ◽  
Vol 4 (1) ◽  
pp. 105-121 ◽  
Author(s):  
E. R. Hiscox ◽  
W. A. Hoy ◽  
K. L. Lomax ◽  
A. T. R. Mattick

It has been shown that neither lactose, nor other sugars tested, casein peptone, nor yeast extract can satisfactorily replace milk as a means of correcting discrepancies which are frequently observed between the plate counts of the 1/100 c.c. and 1/1000 c.c. dilutions of milir on standard agar. Experiments are in progress by which it is hoped that the objections to the addition of milk to standard agar either at the time of making or at the time of plating will be removed, and a medium be evolved which will combine the ease of making and the transparency of standard agar with the efficiency of the medium enriched with milk.


2016 ◽  
Vol 10 (1) ◽  
pp. 13-23 ◽  
Author(s):  
Agustina Arianita Cahyaningtyas ◽  
Wiwik Pudjiastuti ◽  
Ilham Ramdhan

One attempt to reduce the number of pathogenic microbes in milk is through the pasteurization process. This research aims to determine the effect of storage temperature on the organoleptic, acidity (pH) and growth of coliform bacteria in pasteurized milk. Pasteurized milk is stored at the varies of temperature  4°C (observed for 14 days), 10°C-15°C (observed for 14 days) and 25°C-27°C (observed for 22 hours), as well as also conducted an initial analysis pasteurized milk. The parameters were observed among other organoleptic (smell, taste, color, texture), pH and total coliform bacteria. Testing acidity using pH paper, while the growth of coliform bacteria testing done using Total Plate Count method based on ISO 2897 in 2008. The results of this study indicate that storage at 4°C for 14 days, organoleptic pasteurized milk is still good until the day ke- 8, pH progressively decreases, and the growth of coliform bacteria obtained the highest score of 3100x101 CFU / ml. Storage at 10°C-15°C for 14 days, organoleptic pasteurized milk is still good until the 6th day, the pH progressively decreases, and the growth of coliform bacteria obtained the highest score of 5729x101 CFU / ml. Storage at 25°C-27°C for 22 days, organoleptic pasteurized milk is still good until the 9th, pH progressively decreases, and the growth of coliform bacteria obtained the highest score of 4.3 x106 CFU / ml.ABSTRAKSalah satu usaha untuk mengurangi jumlah mikroba patogen pada susu adalah melalui proses pasteurisasi. Penelitian ini bertujuan untuk mengetahui pengaruh suhu penyimpanan terhadap organoleptik, derajat keasaman (pH) dan pertumbuhan bakteri Coliform pada susu pasteurisasi. Susu pasteurisasi disimpan pada suhu yang bervariasi yaitu suhu 4°C (diamati selama 14 hari), suhu 10°C-15°C (diamati selama 14 hari) dan suhu 25°C-27°C (diamati selama 22 jam), serta dilakukan pula analisa awal susu pasteurisasi. Parameter yang diamati antara lain organoleptik (bau, rasa, warna, tekstur), pH dan jumlah bakteri Coliform. Pengujian derajat keasaman menggunakan kertas pH, sedangkan pengujian pertumbuhan bakteri Coliform dilakukan dengan menggunakan metode Total Plate Count berdasarkan SNI 2897 Tahun 2008. Hasil penelitian ini menunjukkan bahwa penyimpanan pada suhu 4°C selama 14 hari, organoleptik susu pasteurisasi masih baik sampai dengan hari ke-8, pH semakin lama semakin menurun, dan pertumbuhan bakteri Coliform didapatkan nilai tertinggi sebesar 3100x101 Cfu/ml. Penyimpanan pada suhu 10°C-15°C selama 14 hari, organoleptik susu pasteurisasi masih baik sampai hari ke-6, pH semakin lama semakin menurun, dan pertumbuhan bakteri Coliform didapatkan nilai tertinggi sebesar 5729x101 Cfu/ml. Penyimpanan pada suhu 25°C-27°C selama 22 hari, organoleptik susu pasteurisasi masih baik sampai jam ke-9, pH semakin lama semakin menurun, dan pertumbuhan bakteri Coliform didapatkan nilai tertinggi sebesar 4,3 x106 Cfu/ml.Kata kunci : bakteri coliform, derajat keasaman, suhu penyimpanan, organoleptik, susu pasteurisasi


Sign in / Sign up

Export Citation Format

Share Document