Destruction de Microbacterium lacticum, Escherichia coli et Staphylococcus aureus au cours du séchage du lait par atomisation. I. Dénombrement sélectif des bactéries survivantes

1977 ◽  
Vol 23 (6) ◽  
pp. 716-720
Author(s):  
A. Chopin ◽  
G. Mocquot ◽  
Y. Le Graet

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 containing 7.5% NaCl. Our results show that physiological injury of the cells during spray-drying differs from injury due to heating only. [Traduit par le journal]

1969 ◽  
Vol 73 (3) ◽  
pp. 183-187
Author(s):  
Fred Fernández-Coll ◽  
Luis Silva-Negrón

Performance of Petrifilm VRB and SM plates to enumerate different types of bacterial populations was evaluated. A total of 100 Petrifilms and 100 regular Petri plates were tested with each of 3 different bacterial populations in 4 experiments. The Petrifilm system was superior to the conventional pour plate methods, or at least not statistically different, in enumerating Escherichia coli (coliform) and a mixture of E. coli, Staphylococcus aureus and Serratia marcescens (total aerobic plate count). The Petrifilm method was superior to conventional plate counts in enumerating Pseudomonas aeruginosa (psychrotrophic plate count), when both incubations were at 21°-22° C for 96 h. If sustained in further experimentation, this last observation would mean that the Petrifilm SM system could be successfully used to detect bacterial populations in addition to those for which the system was originally intended.


2020 ◽  
Vol 12 (2) ◽  
pp. 193-200
Author(s):  
Joko Sapto Pramono ◽  
Mustaming Mustaming ◽  
Dewi Samara Putri

Pempek merupakan makanan tradisional yang berasal dari Palembang. Makanan ini diproduksi oleh industri rumah tangga maupun pabrik pengolah makanan. Olahan ikan ini beresiko dicemari oleh bakteri Escherichia coli, Salmonella, dan Staphylococcus aureus. Penelitian ini bertujuan untuk mengetahui cemaran bakteri pada pempek yang dijual di pasaran kota Samarinda. Jenis penelitian yang digunakan adalah penelitian laboratorium. Teknik sampling yang digunakan yaitu random sampling. Jumlah sampel yang diperoleh sebanyak 20 sampel pempek, 10 sampel produksi industri rumah tangga dan 10 sampel produksi pabrik. Sampel kemudian dibawa ke laboratorium dan dilakukan pemeriksaan jumlah koloni dengan menggunakan colony counter. Hasil penghitungan Angka Lempeng Total (ALT) pada media Plate Count Agar (PCA) menunjukkan bahwa sebanyak 18 sampel (90%) yang terdiri dari 10 sampel pempek produksi pabrik dan 8 sampel pempek produksi rumahan mengandung cemaran mikroba yang tinggi (> 5x 104). Masyarakat disarankan memasak pempek hingga matang sebelum mengkonsumsi baik pempek produksi pabrik maupun produksi rumahan agar terhindar dari resiko cemaran bakteri patogen. Catatan PenerbitPoltekkes Kemenkes Kendari menyatakan tetap netral sehubungan dengan klaim dari perspektif atau buah pikiran yang diterbitkan dan dari afiliasi institusional manapun. PendanaanKajian terlaksana atas pembiayaan sukarela peneliti. Konflik KepentinganPara penulis menyatakan bebas dari konflik kepentingan. Berbagi DataData hasil kajian tersedia melalui permohonan kepada penulis koresponden. Kontribusi PenulisPara penulis tidak mendeklarasikan setiap kontribusinya.


Author(s):  
Susmita Phattepuri ◽  
Prince Subba ◽  
Arjun Ghimire ◽  
Shiv Nandan Sah

Milk is an excellent medium for the growth of many bacteria. This study aimed to determine antibiotic profiling and thermal inactivation of Staphylococcus aureus and Escherichia coli isolated from raw milk of Dharan. Total viable count, total Staphylococcal count, and total coliform count were carried out by conventional microbiological methods. Identification was done on the basis of Gram staining and biochemical tests. The antibiotic susceptibility test of the isolates carried out by the modified Kirby-Baur disc diffusion method. Thermal inactivation of S. aureus and E. coli were carried out by subjecting to thermal treatment in a water bath. Total plate count ranged from 204×104 CFU/mL to 332×105 CFU/mL. Total staphylococcal count and total coliform count ranged from 14×105 CFU/mL to 8×106 CFU/mL and 11×104 CFU/mL to 3×106 CFU/mL respectively. S. aureus showed an increasing resistance patterns towards Ampicillin, Cefotixin, Carbenicillin and Cefotaxime. Ciprofloxacin, Erythromycin, Amikacin, Gentamycin, Azithromycin, and Chloramphenicol were found to be effective against S. aureus. All the E. coli isolates were resistant to Ampicillin and least resistant to Cefotixin. Chloramphenicol, Amikacin, Azithromycin, and Nalidixic acid were found highly effective to E. coli. The D-values for S. aureus at 56°C, 58°C and 60°C were 1.36 min, 1.19 min, and 1.09 min respectively. The Z-value was 14.92°C. While D-values were obtained as 0.98 min, 0.75 min, and 0.57 min for E. coli at 56° C, 58° C and 60° C respectively, and Z-value was 9.75° C. Hence, S. aureus was found to be more heat resistant than E. coli.


1977 ◽  
Vol 40 (6) ◽  
pp. 378-381 ◽  
Author(s):  
C. L. DUITSCHAEVER ◽  
D. H. BULLOCK ◽  
D. R. ARNOTT

A total of 108 samples of fresh refrigerated ground beef, 99 samples of frozen hamburger patties, and 107 fried hamburgers, purchased from retail stores and fast-food outlets in Ontario, were analyzed for their bacteriological quality. About 44% of non-frozen ground beef samples had aerobic plate counts exceeding 50 million/g; 50 of 108 samples (46.3%) contained Staphylococcus aureus and 46 of these 50 samples (88%) exceeded 1000 organisms/g; 43 of 108 samples were positive for Escherichia coli with 38 samples (88.4%) exceeding 500 organisms/g. About 19% of frozen hamburger patties had aerobic plate counts in excess of 10 million/g; 93 of 99 samples (93.9%) contained S. aureus with 83 of these samples (89.3%) exceeding 1000 organisms/g; 28 of 99 samples were positive for E. coli with 7 of these samples (25%) exceeding 500 organisms/g. About 96.3% of fried hamburger samples had aerobic plate counts of less than 10,000/g.


1983 ◽  
Vol 46 (8) ◽  
pp. 710-713
Author(s):  
DOUGLAS F. CAMPBELL ◽  
MARTHA Y. WORKMAN ◽  
GEORGE W. KRUMM ◽  
RALPH W. JOHNSTON

During visits to 20 federally inspected establishments producing meat ravioli, 577 production line samples and 480 finished product units were collected for bacteriological analyses. Four types of finished, packaged ravioli were encountered: (a) whole ravioli boiled at least 5 min; (b) raw pasta stuffed with a cooked filling; (c) only the meat component cooked; and (d) uncooked ravioli. The microbiological quality of frozen ravioli was affected more by the filling than the pasta. Slow freezing resulted in increased bacterial levels in the finished product. For the boiled ravioli, 100% of the finished product sets contained less than 50 coliforms per g, four of five sets had less than one Escherichia coli per g, and 100% had fewer than one Staphylococcus aureus per g. Four of five sets of packaged boiled ravioli had aerobic plate counts (APC) of less than 10,000 per g. For the raw pasta with a cooked filling-type ravioli, the geometric means of 9 sets were: coliforms, 47 per g; E. coli, 6.7 per g; S. aureus, 10 per g; and APC, 170,000 per g. For the ravioli with only the meat component cooked, the geometric means of 27 sets were: coliforms, 190 per g; E. coli, 1.8 per g; S. aureus, 3.9 per g; and APC, 300,000 per g. For uncooked ravioli, the geometric means of 7 sets were: coliforms, 490 per g; E. coli, 19 per g; S. aureus, 5.7 per g; and APC, 690,000 per g. Only one finished ravioli unit in 480 contained Salmonella.


1986 ◽  
Vol 49 (3) ◽  
pp. 233-235 ◽  
Author(s):  
PATRICIA HAGGERTY ◽  
NORMAN N. POTTER

Studies were made to compare the growth and death of Staphylococcus aureus, Streptococcus faecalis and Escherichia coli in skim milk concentrated by ultrafiltration to that in unconcentrated skim milk. Skim milk was volume concentrated to 2× in laboratory-scale stirred UF cells. Behavior of the organisms was analyzed in four inoculated milk samples: 2× retentate, 1× water-diluted retentate, milk equivalent (retentate plus permeate) and unconcentrated skim milk. Growth of each organism and of total aerobes did not vary in the four milk samples at either 7 or 13°C. For S. faecalis and E. coli, D-values for samples heated to 62.7°C did not significantly differ in the four milk samples (p>0.01). The D-value of S. aureus in water-diluted retentate was slightly but significantly lower than those in the other three milk samples (p<0.01), possibly due to the lowered lactose level in this sample.


2021 ◽  
Vol 8 (2) ◽  
pp. 193-204
Author(s):  
Ulfa Dwi Karisma ◽  
Nurul Wiqoyah ◽  
Suhintam Pusarawati

Foodborne disease is a disease caused by contaminated food. Chicken meat is very susceptible to contamination by bacteria. Escherichia coli, Salmonella sp, and Staphylococcus aureus are types of bacteria found in chicken meat. The purpose of this study was to see how many Escherichia coli, Salmonella sp, and Staphylococcus aureus colonies in raw chicken meat in traditional markets in Surabaya City. The research sample used was 30 samples of chicken meat taken in 5 traditional markets in Surabaya. Six chicken meat sellers were taken with 1 sample and put in the sterile tube from each market. The test was carried out using the Total Plate Count (TPC) method. The TPC test results showed that all samples were contaminated with E. coli, with the most colony being 2.2X10-7 CFU/g while the minor colony was 5X10-4 CFU/g. There are two samples contaminated with Salmonella sp, in the G market and the W market, with code D6 4.7X10-6 CFU/g and code E5 1X10-6 CFU/g. Meanwhile, S. aureus was only found in the W market with sample codes E1 & E6, and each sample had a colony of 2.7X 10-7 CFU/g and 2X10-5 CFU/g.


1989 ◽  
Vol 52 (9) ◽  
pp. 631-637 ◽  
Author(s):  
JEFFREY L. KORNACKI ◽  
ELMER H. MARTH

Cells of Staphylococcus aureus strains 196E, 481, and 425 were thermally stressed at 56°C for 10 min in milk and enumerated on Plate Count Agar (PCA), Mannitol Salt Agar (MSA), and PCA with an overlay of MSA. PCA recovered more S. aureus 196E and 481 than did PCA/MSA, which recovered more than MSA. PCA/MSA recovered slightly more S. aureus 425 than did PCA, which recovered more than MSA. At 58°C, in order of decreasing heat resistance, the four strains of S. aureus originally isolated from food were 425 > 100 and 481 > 196E. Their D-values were 26,14,13, and 3.0 min, respectively. S. aureus 425 was more heat resistant in the stationary than in the log phase when heated at 58°C in whole milk. Heat resistance at 58°C increased overall during the stationary growth phase, but was fairly stable when the culture was from 17 to 25 h or from 41 to 49 h old. S. aureus 425 exhibited no consistent differences in heat resistance in concentrated (4X by volume) and unconcentrated skim or whole milk. Adjustments of protein (3.5–4.0% to 12.6–16%), milkfat (0.28–1.12% to 10%), and lactose (ca. 4.5–5.0% to ca. 14.5–15%) contents of milk and 4X (volume concentration) UF milk retentates afforded no significant thermal protection to S. aureus 425. Diafiltration of 4X skim milk reduced thermal protection of S. aureus 425 in the retentate over that of unconcentrated skim milk of the same lot when tested at 63 and 74°C. S. aureus 425 had greatest D-values (min) in skim milk (0.36 ± 0.05) and permeate (0.30 ± 0.14) followed by permeate from diafiltration (0.28 ± 0.06) when tested at 63°C.


1984 ◽  
Vol 47 (5) ◽  
pp. 394-397 ◽  
Author(s):  
H. S. LILLARD ◽  
N. A. COX ◽  
J. S. BAILEY ◽  
J. E. THOMSON

Five brands of media (BBL, Difco, Gibco, Oxoid and Scott) were evaluated for enumerating microorganisms by the aerobic plate count and by Enterobacteriaceae, Escherichia coli, and coliform counts, and for determining Salmonella incidence. Microbiological evaluations were done on raw chickens, raw beef and raw shrimp, except that Salmonella incidence was not determined on shrimp samples. There were statistically significant differences in total plate counts (with chicken, beef and shrimp), Enterobacteriaceae counts (with shrimp) coliforms (with chicken) and E. coli counts (with chicken) by the five brands of media, but these differences were too small to be of practical significance. It was concluded that no differences of practical significance were found among the five brands of media.


2006 ◽  
Vol 69 (10) ◽  
pp. 2500-2503 ◽  
Author(s):  
P. PAULSEN ◽  
E. SCHOPF ◽  
F. J. M. SMULDERS

An automated most-probable-number (MPN) system for the enumeration of total bacterial flora and Escherichia coli was compared with plate count agar and tryptone-bile-glucuronide (TBX) and ColiID (in-house method) agar methodology. The MPN partitioning of sample aliquots was done automatically on a disposable card containing 48 wells of 3 different volumes, i.e., 16 replicates per volume. Bacterial growth was detected by the formation of fluorescent 4-methylumbilliferone. After incubation, the number of fluorescent wells was read with a separate device, and the MPN was calculated automatically. A total of 180 naturally contaminated samples were tested (pig and cattle carcass surfaces, n = 63; frozen minced meat, n = 62; and refrigerated minced meat, n = 55). Plate count agar results and MPN were highly correlated (r = 0.99), with log MPN =−0.25 + 1.05·log CFU (plate count agar) (n = 163; range, 2.2 to 7.5 log CFU/g or cm2). Only a few discrepancies were recorded. In two samples (1.1%), the differences were ≥1.0 log; in three samples (1.7%), the differences were ≥0.5 log. For E. coli, regression analysis was done for all three methods for 80 minced meat samples, which were above the limit of detection (1.0 log CFU/g): log MPN = 0.18 + 0.98·log CFU (TBX), r = 0.96, and log MPN =−0.02 + 0.99·log CFU (ColiID), r = 0.99 (range, 1.0 to 4.2 log CFU/g). Four discrepant results were recorded, with differences of >0.5 but <1.0 log unit. These results suggest that the automated MPN method described is a suitable and labor-saving alternative to colony count techniques for total bacterial flora and E. coli determination in minced meat or on carcass surfaces.


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