Behavior of Enterobacter aerogenes and Hafnia Species During the Manufacture and Ripening of Camembert Cheese

1979 ◽  
Vol 42 (10) ◽  
pp. 790-793 ◽  
Author(s):  
J. L. RUTZINSKI ◽  
E. H. MARTH ◽  
N. F. OLSON

Camembert cheese was made from pasteurized milk contaminated with about 102–103 cells of Enterobacter aerogenes or Hafnia sp. The coliform bacteria were enumerated with a Most Probable Number procedure and with violet red bile agar. Numbers of viable E. aerogenes decreased rapidly during ripening at 15.5 or 10 C when cheese was made with the commercial lactic starter cultures OD or C-5. No viable E. aerogenes was detected in cheese ripened at 10 C for 3 weeks. Ripening of cheese, made with starter culture OD or C-5, for 1 week at 15.5 C was accompanied by a decrease in numbers of viable Hafnia sp. to 10/g. The number of Hafnia sp. increased markedly during 7 weeks of further ripening at 10 C to yield cheese which contained numbers in excess of 107/g when ripening was almost completed. Growth of Hafnia sp. during the storage period coincided with an increase in pH of the cheese.

1973 ◽  
Vol 36 (11) ◽  
pp. 543-546 ◽  
Author(s):  
H. S. Park ◽  
E. H. Marth ◽  
N. F. Olson

Camembert cheese was made from pasteurized milk inoculated to contain, per milliliter, approximately 100 cells of enteropathogenic strains of Echerichia coli. A Most Probable Number technique was used to enumerate E. coli at intervals during manufacture and ripening of the cheese. Identity of isolates obtained was determined serologically. Growth of E. coli was minimal until after curd was cut and hooped. Rapid growth ensued and populations in excess of 104/g appeared in some Cheeses 5 h after the Cheesemaking process began. Overnight storage of Cheese in hoops was accompanied by a decline in numbers of viable E. coli. This coincided with a drop in pH of the Cheese to 5.0 or below. Salting of cheese and 1 day of ripening at 15.6 C ( 60 F) caused a further decline in number of viable E. coli. This decline continued during the rest of the week at 15.6 C ( 60 F) and during storage at 10 C (50 F). From 0 to 9 weeks at 10 C (50 F) were required before cheese was free of viable E. coli. Substitution of Streptococcus cremoris C1 for a commercial lactic starter culture favored survival of E. coli so that 9-week old Cheese contained >104/g. When cheese was made from milk that contained penicillin, the E. coli population was approximately 109/g in 24-h old cheese and 107/g when the Cheese was 9 weeks old.


1998 ◽  
Vol 61 (6) ◽  
pp. 688-692 ◽  
Author(s):  
DEMETRIOS K. PAPAGEORGIOU ◽  
AMIN ABRAHIM ◽  
MINA BORI ◽  
SPIROS DOUNDOUNAKIS

Sixty-two samples of Pichtogalo Chanion cheese traditionally produced in Crete, a few (3 to 6) days old, were analyzed for some chemical and bacteriological characteristics. The results of physicochemical analyses were as follows: (1) moisture content 61.63% (standard deviation 4.67); (2) fat in dry matter 54.03% (SD 7.73); (3) protein content 14.23% (SD 1.72); (4) salt content 1.02% (SD 0.38); (5) water activity (aw) 0.990 (SD 0.003); and (6) pH 4.36 (SD 0.25). None of the samples yielded Salmonella spp. Listeria monocytogenes and coagulase-positive staphylococci were present in 6.45% of the samples. Bacillus cereus and sulfite-reducing clostridia were isolated from 14.51% and 40.32% of the samples, respectively. High populations of coliforms were determined in the cheese samples. In 11.3% of the samples, Escherichia coli was not detected, while 88.7% of the samples yielded E. coli most probable number levels from 1.32 to 5.66 log10/g. The log10 CFU/g counts of enterococci were 6.89 (SD 0.84), of yeasts 6.79 (SD 0.61), of molds 4.68 (SD 0.69), and of psychrotrophic bacteria 7.63 (SD 0.62). The log10 CFU/g counts of lactic acid streptococci and lactococci were 7.91 (SD 0.68) and of lactobacilli 8.11 (SD 0.65). Lactic acid bacteria, mainly mesophilic, were isolated and confirmed using API 50 CH test trips. A pasteurized mixture of ewe's and goat's milk was made into Pichtogalo Chanion cheese according to standard procedure at 23°C, after the addition of 4% commercial mesophilic starter culture or 2%, 3%, and 4% starter culture of the isolated and confirmed lactic acid bacteria and the addition of rennet. Results of this work indicated that high quality of Pichtogalo Chanion cheese can be produced using a pasteurized mixture of ewe's and goat's milk and 4% (vol/vol) of mesophilic starter culture.


2020 ◽  
pp. 32-44
Author(s):  
Hanaa M. A. Salih ◽  
Mohamed O. M. Abdalla

Aims: This study was conducted to determine the effect of starter culture addition on the physicochemical, microbiological and sensory characteristics of white cheese (Gibna Bayda) during the storage period (5°C/ 45 days). Methodology: Two treatments were prepared: Treatment 1 (T1): cheese manufactured with pasteurized milk with Lactobacillus bulgaricus and Streptococcus thermophilus (1:1) at the level of 2% (w/v); Treatment 2 (T2): the control; cheese manufactured with pasteurized milk without starter cultures. After cheese manufacture, physicochemical, microbiological and sensory characteristics were determined at 1, 15, 30 and 45-day intervals. Results: Results showed that the starter culture addition did not significantly (P>.05) affect all physiochemical characteristics of cheese, except for the ash content which was high in cheese manufactured with the addition of starter culture. The addition of the starter influenced the microbiological quality of the cheese, with total viable bacteria, Staphylococcus aureus and yeasts and moulds counts being significantly (P<.05) low. Furthermore, the cheese made with an added starter culture showed high scores of colour, taste and flavour. The storage period significantly affected all characteristics of the cheese, except for the fat content of the control, which remained unchanged during all storage periods. Conclusion: The results of this study show that starter culture (Lactobacillus bulgaricus and Streptococcus thermophilus) (1:1) is likely to be a suitable culture for Sudanese white cheese.


2020 ◽  
Vol 2 (2) ◽  
Author(s):  
Wanda Aulya ◽  
Fadhliani Fadhliani ◽  
Vivi Mardina

Water is the main source for life and also the most severe substance caused by pollution. The mandatory parameters for determining microbiological quality of drinking water are total non-fecal Coliform bacteria and Coliform fecal (Escherichia coli). Coliform bacteria are a group of microorganisms commonly used as indicators, where these bacteria can be a signal to determine whether a water source has been contaminated by bacteria or not, while fecal Coliform bacteria are indicator bacteria polluting pathogenic bacteria originating from human feces and warm-blooded animals (mammals) . The water inspection method in this study uses the MPN (Most Probable Number) method which consists of 3 tests, namely, the presumption test, the affirmation test, and the reinforcement test. The results showed that of 15 drinking water samples 8 samples were tested positive for Coliform bacteria with the highest total bacterial value of sample number 1, 15 (210/100 ml), while 7 other samples were negative. From 8 positive Coliform samples only 1 sample was stated to be negative fecal Coliform bacteria and 7 other samples were positive for Coliform fecal bacteria with the highest total bacterial value of sample number 1 (210/100 ml).


2019 ◽  
Vol 2 (2) ◽  
pp. a13-19
Author(s):  
ELEXSON NILLIAN ◽  
AMIZA NUR ◽  
DIYANA NUR ◽  
AMIRAH ZAKIRAH ◽  
GRACE BEBEY

Contamination of drinks with E. coli O157:H7 served in food premises such as restaurants can cause haemorrhagic colitis and haemolytic uremic syndrome to humans. The presence or absence of faecal pathogen was demonstrated using coliform group as indicator microorganisms. Therefore, this study was conducted to detect the presence of E. coli O157:H7 in drinking water from food restaurant premise in Kota Samarahan and Kuching to ensure safe and potable drinking water is served to the consumer. A total of thirty (n=30) drink samples including six types of each of the samples are cold plain water, iced tea, iced milo, syrup and iced milk tea. Most Probable Number (MPN) procedure was used in this study to enumerate the MPN values of coliform bacteria in each drink collected. A total of 53.33% (16/30) of the drink samples showed positive E. coli detection. Then, the PCR assay showed 6.25% (one out of 16 isolates) samples were positive and carried stx1 gene produced by E. coli O157:H7 in iced milo sample types. This study showed the drinks collected from food premises was contaminated with faecal contamination, which was not safe to drink by the consumer. Therefore, preventive actions should be taken to prevent foodborne illness outbreak in future


2019 ◽  
Vol 6 (1) ◽  
pp. 61
Author(s):  
Nenengsih Verawati ◽  
Nur Aida ◽  
Ridha Aufa

Tofu is a high-protein soy-based food ingredient that is widely consumed in Indonesia. Tofu producers in Delta Pawan Subdistrict are dominated by small and medium-sized entrepreneurs whose hygiene and sanitation aspects in production activities are very under-taken. This study aims to determine the presence of Coliform and Salmonella Sp bacteria on tofu produced in Delta Pawan sub-district, Ketapang, West Kalimantan and compare with SNI01-3142-1998. The method used to detect the presence of Coliform bacteria in this study uses the Most Probable Number (MPN) method, which consists of estimator and confirmatory tests using Lactosa Broth (LB) media for the Brilliant Green Lactose Broth (BGLB) assay test for confirmation . Whereas to detect the amount of Salmonella Sp using the method of Total Plate Count (TPC) with selective media Salmonella Shigella Agar (SSA). The results of Coliform analysis in both industries found Coliform MPN values ​​of more than 2400 AMP / g samples, which indicated that they did not meet the standards set by SNI. While the results of the analysis of Salmonella Sp obtained positive results, so the two industries did not meet food safety standards.


1980 ◽  
Vol 43 (7) ◽  
pp. 563-563
Author(s):  
E. P. MERRILL

Of 658 individual water supplies tested over an 8-year period, 69% of drilled wells, 62% of driven wells, 27% of dug wells and 32% of springs were judged acceptable on the basis of a single test for total coliforms. The acceptability standard consisted of 0 to 1 coliforms/100 ml of sample by the membrane filter method or a Most Probable Number index of less than 2.2 (presumptive and confirmed tests).


1991 ◽  
Vol 54 (7) ◽  
pp. 532-536 ◽  
Author(s):  
GERALDINE M. FARRELL ◽  
AHMED E. YOUSEF ◽  
ELMER H. MARTH

Autoclaved whole milk, low-fat milk, protein-fortified skim milk and regular skim milk were inoculated to contain ca. 105 to 106 Borrelia burgdorferi strains 35210, 35211, or EBNI/ml and stored at 34°C for 16 d. Similarly inoculated skim milk also was held at 5°C for 46 d. Numbers of survivors were estimated by the Most Probable Number (MPN) technique. In all instances, numbers of B. burgdorferi decreased over the storage period. At 34°C, no strain of B. burgdorferi was detected after day 12. The mean D-values, at 34°C, for strains 35210, 35211, and EBNI were 2.2, 2.4, and 2.2 d, respectively. The mean D-values, at 34°C, for all strains in whole milk, low-fat milk, protein-fortified skim milk, and regular skim milk were 2.4, 2.3, 1.9, and 2.4 d, respectively. At 5°C, spirochete numbers in regular skim milk decreased, but all three strains remained at a detectable level for 46 d. The mean D-values, at 5°C, for strains 35210, 35211, and EBNI were 12, 15, and 12 d, respectively.


1978 ◽  
Vol 24 (12) ◽  
pp. 1574-1582 ◽  
Author(s):  
Lai-King Ng ◽  
Michael E. Stiles

Presumptive Escherichia coli counts for 312 samples of non-frozen ground beef were determined and compared with proposed Canadian standards. Results for frozen pork sausages, packaged at manufacturer level, indicated little difference in distribution of presumptive E. coli loads compared with retail ground beef. Use of solid media and direct inoculation of EC broth at 45 °C did not give alternative, rapid methods of estimating E. coli loads in ground beef. Counts on violet red bile agar (VRBA) within 18–24 h incubation at 35 °C gave reliable estimates of coliform bacteria (bile-precipitating colonies) and Enterobacteriaceae (total count), with only 1.3 and 10.7% false positives, respectively. Bile-precipitating isolates from VRBA were primarily E. coli, also Serratia liquefaciens, aerogenic Enterobacter agglomerans, Enterobacter cloacae, Citrobacter freundii, and Klebsiella pneumoniae. Non-bile-precipitating colonies were primarily aerogenic E. agglomerans and S. liquefaciens; however, in the most probable number technique E. agglomerans was screened out. In addition to E. coli, E. agglomerans and S. liquefaciens were the principal types of Enterobacteriaceae in these samples. Enterobacter agglomerans gave a variety of IMViC reactions, including the type I (++−−) reaction, whereas S. liquefaciens were predominantly IMViC type −−++. Incubating EC broth at 45.5 °C, as opposed to 44.5 °C, reduced the number of false positives.


1988 ◽  
Vol 51 (5) ◽  
pp. 386-390 ◽  
Author(s):  
Y. A. EL-SAMRAGY ◽  
E. O. FAYED ◽  
A. A. ALY ◽  
A. E. A. HAGRASS

The traditional yogurt starter, i.e. Staphylococcus thermophilus and Lactobacillus bulgaricus, has always been used to bring about the lactic acid fermentation during manufacture of concentrated yogurt known in Egypt as “Labneh”. Different combinations of some strains of Enterococcus faecalis, isolated from Laban Rayeb (a type of fermented milk), in combination with a certain strain of Lactobacillus bulgaricus were used to produce a Labneh-like product. Chemical, microbiological and organoleptic properties of the Labneh-like product were assessed and compared to the characteristics of Labneh processed traditionally by two different dairy plants in Egypt. All treatments showed similar changes during storage at 5 ± 1°C for 28 d. Total solids, fat, titratable acidity and pH values coincided with those of Labneh. Some components increased until the seventh day, i.e. acetaldehyde and diacetyl, while other features, such as the ratio of soluble nitrogen/total nitrogen and tyrosine, increased until the fourteenth day of storage. Thereafter, no marked variations occurred. However, a decrease in tryptophan content of all products occurred during the storage period. Total viable count and count of lactic acid bacteria of Labneh-like product as well as Labneh increased until the end of the second week of storage and then decreased. Coliforms, yeasts and molds and psychrotrophic bacteria were detected in some fresh and stored samples. The starter culture which consisted of 1.5% Enterococcus faecalis 19 and 1.5% Enterococcus faecalis 22 was used successfully to manufacture a Labneh-like product with high acceptability when fresh or refrigerated at 5 ± 1°C.


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