scholarly journals Quantitative Microbiological Analysis of Artisanal Stretched Cheese Manufacture

2021 ◽  
Vol 11 (6) ◽  
pp. 2680
Author(s):  
Veronika Lehotová ◽  
Veronika Antálková ◽  
Alžbeta Medveďová ◽  
Ľubomír Valík
Keyword(s):  
Early Stage ◽  
Storage Period ◽  
Coliform Bacteria ◽  
Microbiological Analysis ◽  
E Coli ◽  
Log Reduction ◽  
Milk Coagulation ◽  
Yeasts And Molds ◽  
Entire Storage Period ◽  
Cheese Production

To evaluate the behavior of the relevant microbial populations during stretched cheese production, quantitative microbiological analysis was performed during the critical steps of the preparation. The obtained data distributions proved statistically significant increases in all indicators, on average by 4.55 ± 0.64 log CFU/g of presumptive lactococci counts, 4.06 ± 0.61 of lactobacilli, 1.53 ± 0.57 log CFU/g of coliforms, 2.42 ± 0.67 log CFU/g of Escherichia coli, 1.53 ± 0.75 log CFU/g of yeasts and molds, and 0.99 ± 0.27 log CFU/g of presumptive Staphylococcus aureus, from the early stage of milk coagulation until curd ripening (0–24 h). The following steaming/stretching process caused reductions in viable counts with the most significant inactivation effect on coliform bacteria, including E. coli (−4.0 ± 1.0 log CFU/g). Total viable counts and yeasts and molds showed 2 and almost 3 log reduction (−2.2 ± 1.1 log CFU/g and −2.6 ± 0.9 log CFU/g), respectively. The lowest decreases in presumptive S. aureus counts were estimated at the level of −1.50 ± 0.64 log CFU/g. The counts of yeasts and molds showed the best indicatory function during the entire storage period of vacuum-packaged cheeses at 6 °C.

scholarly journals Quantitative Microbiological Analysis of Artisanal Stretched Cheese Manufacture

2021 ◽  
Author(s):  
Veronika Lehotová ◽  
Veronika Antálková ◽  
Alžbeta Medveďová ◽  
Ľubomír Valík
Keyword(s):  
Early Stage ◽  
Storage Period ◽  
Coliform Bacteria ◽  
Microbiological Analysis ◽  
E Coli ◽  
Log Reduction ◽  
Milk Coagulation ◽  
Entire Storage Period ◽  
Stretching Process ◽  
Cheese Production

To evaluate the behaviour of the relevant microbial populations during stretched cheese production, the quantitative microbiological analysis was performed during the critical steps of the preparation. The obtained data distributions proved statistically significant increases in all indicators, on average by 4.55 ± 0.64 log CFU/g of presumptive lactococci counts, 4.06 ±0.61 of lactobacilli, 1.53 ± 0.57 log CFU/g of coliforms, 2.42 ± 0.67 log CFU/g of Escherichia coli, 1.53 ± 0.75 log CFU/g of yeasts and moulds, and 0.99 ± 0.27 log CFU/g of presumptive Staphylococcus aureus, from the early stage of milk coagulation until curd ripening (0–24 h). The following steaming/stretching process caused reductions in viable counts with the most significant inactivation effect on coliform bacteria, including E. coli (-4.0 ± 1.0 log CFU/g). Total viable counts and yeasts and moulds showed 2 and almost 3 log reduction (-2.2 ± 1.1 log CFU/g and -2.6 ± 0.9 log CFU/g), respectively. The lowest decreases in presumptive S. aureus counts were estimated at the level of -1.50 ± 0.64 log CFU/g. The counts of yeasts and moulds showed the best indicatory function during the entire storage period of vacuum-packaged cheeses at 6 °C.

Death of Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes in Shelf-Stable, Dairy-Based, Pourable Salad Dressings

2006 ◽  
Vol 69 (4) ◽  
pp. 801-814 ◽  
Author(s):  
LARRY R. BEUCHAT ◽  
JEE-HOON RYU ◽  
BARBARA B. ADLER ◽  
M. DAVID HARRISON
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Storage Period ◽  
Escherichia Coli O157 ◽  
Blue Cheese ◽  
Initial Inoculum ◽  
E Coli ◽  
Reduced Fat ◽  
Yeasts And Molds ◽  
Shelf Stable

The objectives of this study were to determine the death rates of Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes in three commercially manufactured full-fat ranch salad dressings, three reduced-fat ranch salad dressings, two full-fat blue cheese salad dressings, and two reduced-fat blue cheese salad dressings and to affirm the expectation that these dressings do not support the growth of these pathogens. The respective initial pH values of the four types of shelf-stable, dairy-based, pourable dressings were 2.87 to 3.72, 2.82 to 3.19, 3.08 to 3.87, and 2.83 to 3.49, respectively. Dressings were inoculated with low (2.4 to 2.5 log CFU/g) and high (5.3 to 5.9 log CFU/g) populations of separate five-strain mixtures of each pathogen and stored at 25°C for up to 15 days. Regardless of the initial inoculum population, all test pathogens rapidly died in all salad dressings. Salmonella was undetectable by enrichment (<1 CFU/25-ml sample in three replicate trials) in all salad dressings within 1 day, and E. coli O157:H7 and L. monocytogenes were reduced to undetectable levels by enrichment between 1 and 8 days and 2 and 8 days, respectively. E. coli O157:H7 was not detected in 4 of the 10 salad dressings stored for 2 or more days and 9 of the 10 dressings stored for 6 or more days after inoculation. L. monocytogenes was detected in 9 of the 10 salad dressings stored for 3 days but in only one dressing, by enrichment, at 6 days, indicating that it had the highest tolerance among the three pathogens to the acidic environment imposed by the dressings. Overall, the type of dressing (i.e., ranch versus blue cheese) and level of fat in the dressings did not have a marked effect on the rate of inactivation of pathogens. Total counts and populations of lactic acid bacteria and yeasts and molds remained low or undetectable (<1.0 log CFU/ml) throughout the 15-day storage period. Based on these observations, shelf-stable, dairy-based, pourable ranch and blue cheese salad dressings manufactured by three companies and stored at 25°C do not support the growth of Salmonella, E. coli O157:H7, and L. monocytogenes and should not be considered as potentially hazardous foods (time-temperature control for safety foods) as defined by the U.S. Food and Drug Administration Food Code.

Inactivation of Saccharomyces cerevisiae and Polyphenoloxidase in Mango Nectar Treated with UV Light

2006 ◽  
Vol 69 (2) ◽  
pp. 362-368 ◽  
Author(s):  
JOSÉ A. GUERRERO-BELTRÉN ◽  
GUSTAVO V. BARBOSA-CÉNOVAS
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Uv Light ◽  
Storage Period ◽  
Microbial Load ◽  
Microbial Count ◽  
Uv Treatment ◽  
Log Reduction ◽  
First Order Kinetics ◽  
Yellow Orange ◽  
Entire Storage Period

Fresh mango nectar was processed by UV light at five flow rates (0.073 to 0.451 liter/min) and five UV light doses (75 to 450 kJ/m2) to evaluate total microbial load, Saccharomyces cerevisiae survival, and polyphenoloxidase activity. UV systems containing an inner mercury lamp (254 nm) each with intensity of 25 mW/cm2 were used as germicidal sources. In addition, mango nectar was treated for 15 min at 0.073 and 0.451 liter/min, stored at 3°C, and evaluated periodically for total microbial count, yeast count, color, and polyphenoloxidase activity. The first-order kinetics modeling found that DUV-values in mango nectar ranged from 27.9 to 10.9 min (R2 > 0.950) and 26.0 to 11.8 min (R2 > 0.962) for total microbial count and yeast count, respectively. The maximum log reduction (CFU per milliliter) was 2.71 and 2.94 for total microbial count and yeast count, respectively, after 30 min of UV treatment at 0.451 liter/min. DUV-values ranging from 156 to 204 min were observed for polyphenoloxidase activity. The remaining polyphenoloxidase activity after 30 min of UV treatment at 0.451 liter/min was 19 ± 4%. Initial microbial load and yeast in stored mango nectar were reduced in the range 2.86 to 3.41 and 1.82 to 1.97 log (CFU/ml) cycles, respectively. No substantial microbial growth was observed prior to 20 days of storage. Averages of 1,055 ± 32, 803 ± 32, and 710 ± 37 enzyme activity units were observed in mango nectar UV processed at 0, 0.073, and 0.451 liter/min, respectively, during the entire storage period. However, mango nectar treated at 0.073 and 0.451 liter/min maintained a yellow and yellow-orange color, respectively, after 26 days of storage.

Antimicrobial Effects of Alginate-Based Film Containing Essential Oils for the Preservation of Whole Beef Muscle

2006 ◽  
Vol 69 (10) ◽  
pp. 2364-2369 ◽  
Author(s):  
MOUNIA OUSSALAH ◽  
STÉPHANE CAILLET ◽  
STÉPHANE SALMIÉRI ◽  
LINDA SAUCIER ◽  
MONIQUE LACROIX
Keyword(s):  
Essential Oils ◽  
Salmonella Typhimurium ◽  
Storage Period ◽  
Edible Films ◽  
Total Phenolic ◽  
Microbiological Analysis ◽  
Active Compounds ◽  
E Coli ◽  
Beef Muscle

Alginate-based edible films containing 1% (wt/vol) essential oils of Spanish oregano, Chinese cinnamon, or savory were immersed in 2% (wt/vol) or 20% (wt/vol) CaCl2 solution and then applied to beef muscle slices to control the growth of Escherichia coli O157:H7 and Salmonella Typhimurium. Whole beef muscle surfaces were inoculated with one of these strains at 103 CFU/cm2. During the 5 days of storage, samples of meat were obtained periodically for microbiological analysis. The availability of active compounds from essential oils present in films was evaluated by determination of total phenolic compounds for oregano- and savory-based films and of total aldehydes for cinnamon-based films during storage. After 5 days of storage, films containing oregano or cinnamon essential oils were the most effective against Salmonella Typhimurium regardless of the type of pretreatment used (2 or 20% CaCl2). During the same period, meat inoculated with E. coli O157:H7 and coated with films treated with 2% CaCl2 had significantly fewer bacteria (P ≤ 0.05) when oregano-based films were used than when cinnamon- and savory-based films were used. The E. coli O157:H7 concentration was higher at the end of the storage period when films were pretreated with 20% CaCl2. Evaluation of the active compounds in films revealed that availability in oregano-and savory-based films was significantly more important (P ≤ 0.05) than that in cinnamon-based films regardless of the type of pretreatment used (2 or 20% CaCl2). At the end of storage, release rates of 40, 60, and 77% were noted in oregano-, savory-, and cinnamon-based films in 2% CaCl2 and rates of 65, 62, and 90% were noted in the same films in 20% CaCl2.

Survival of Shiga Toxin–Producing Escherichia coli in Various Wild Animal Feces That May Contaminate Produce

2020 ◽  
Vol 83 (8) ◽  
pp. 1420-1429
Author(s):  
ZEYNAL TOPALCENGIZ ◽  
SAHARUETAI JEAMSRIPONG ◽  
PATRICK M. SPANNINGER ◽  
ANIL K. PERSAD ◽  
FEI WANG ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Storage Period ◽  
Wild Animal ◽  
E Coli ◽  
Similar Survival ◽  
Entire Storage Period ◽  
Food Safety Risk ◽  
Animal Feces ◽  
Feral Pig

ABSTRACT Domestic and wild animal intrusions are identified as a food safety risk during fresh produce production. The purpose of this study was to evaluate the survival of Shiga toxin–producing Escherichia coli (STEC) in cattle, feral pig, waterfowl, deer, and raccoon feces from sources in California, Delaware, Florida, and Ohio. Fecal samples were inoculated with a cocktail of rifampin-resistant STEC serotypes (O103, O104, O111, O145, and O157) (104 to 106 CFU/g of feces). Inoculated feces were held at ambient temperature. Populations of surviving cells were monitored throughout 1 year (364 days), with viable populations being enumerated by spread plating and enrichment when the bacteria were no longer detected by plating. Representative colonies were collected at various time intervals based on availability from different locations to determine the persistence of surviving STEC serotypes. Over the 364-day storage period, similar survival trends were observed for each type of animal feces from all states except for cattle and deer feces from Ohio. STEC populations remained the highest in cattle and deer feces from all states between days 28 and 364, except for those from Ohio. Feral pig, waterfowl, and raccoon feces had populations of STEC of <1.0 log CFU/g starting from day 112 in feces from all states. E. coli O103 and O104 were the predominant serotypes throughout the entire storage period in feces from all animals and from all states. The survival of both O157 and non-O157 STEC strains in domesticated and wild animal feces indicates a potential risk of contamination from animal intrusion. HIGHLIGHTS

Combined Chitosan-Thyme Treatments with Modified Atmosphere Packaging on a Ready-to-Cook Poultry Product

2010 ◽  
Vol 73 (4) ◽  
pp. 663-669 ◽  
Author(s):  
V. GIATRAKOU ◽  
A. NTZIMANI ◽  
I. N. SAVVAIDIS
Keyword(s):  
Essential Oil ◽  
Shelf Life ◽  
Modified Atmosphere Packaging ◽  
Storage Period ◽  
Modified Atmosphere ◽  
Sensory Data ◽  
Thyme Essential Oil ◽  
Brochothrix Thermosphacta ◽  
Yeasts And Molds ◽  
Entire Storage Period

In the present study, natural antimicrobials chitosan and thyme, and their combination, were evaluated for their effect on the shelf life of a ready-to-cook (RTC) chicken-pepper kebab (skewer) stored under modified atmosphere packaging (MAP) conditions at 4 ± 0.5°C for 14 days. The following treatments were examined: control samples stored under aerobic packaging (A), samples stored under MAP (M), samples treated with 1.5% chitosan (vol/wt) and stored under MAP (M-CH), samples treated with 0.2% thyme essential oil (vol/wt) (M-T), and samples treated with 1.5% chitosan (vol/wt) and 0.2% thyme essential oil (vol/wt) and stored under MAP (M-CH-T). Treatment M-CH-T significantly affected aerobic plate counts and counts of lactic acid bacteria, Pseudomonas spp., Brochothrix thermosphacta, Enterobacteriaceae, and yeasts and molds during the entire storage period. Similarly, lipid oxidation of the RTC product was retarded (M-CH-T treatment) during storage, whereas redness was maintained in M-T, M-CH, and M-CH-T samples. Based primarily on sensory data (taste attribute), M-CH and M-T treatments extended RTC product shelf life by 6 days, whereas M-CH-T treatment resulted in a product with a shelf life of 14 days that maintained acceptable sensory characteristics (shelf life of the control was 6 days).

scholarly journals The Role of Probiotic Bacteria on Microbiological and Acceptability of Sudanese White Soft Cheese

2021 ◽  
Vol 04 (05) ◽  
Author(s):  
Alwaleed Ibrahim Dafalla ◽  
Keyword(s):  
Pathogenic Bacteria ◽  
Storage Period ◽  
Bifidobacterium Bifidum ◽  
Probiotic Bacteria ◽  
Coliform Bacteria ◽  
Microbiological Analysis ◽  
Overall Acceptability ◽  
Soft Cheese ◽  
Microbial Analysis

The objectives of this investigation is to study the effect of three types of probiotic bacteria (Lactobacilus rhamnosus, Lactobacillus casei, Bifidobacterium bifidum) on the microbiological and acceptability of Sudanese white soft cheese during storage period 0, 15, 30, 45 and 60 days. Microbiological analysis revealed that, the highest count of probiotic bacteria (87x108cfu/g) was obtained by sample containing L.rhamnosus and the lowest (39x106 cfu/g) by sample containing B.bifidum, while the sample containing L.casei ranked in intermediate position. Storage period affected the total probiotic bacteria count, the highest count at 2 weeks for L.casei and B.bfidum and after 4 weeks for L.rhamnosus, while the lowest at the end. The microbial analysis did not detect any pathogenic bacteria (coliform bacteria, salmonella and staphylococcus aureus) or yeast and molds. The sensory evaluation quality revealed that the cheese containing L.rhamnosus gave the best appearance, texture, flavour and overall acceptability, followed by L.casei and B.bifidum compared with the control samples. The storage period significantly (p≤0.05) affected the acceptability of the cheese, where the highest score was obtained at day 30 and the lowest at the beginning of the storage. The study recommends further studies and tests to improve the quality of the Sudanese white soft cheese treated by probiotic bacteria.

scholarly journals Evaluation of the Microbiological and Physico-Chemical Quality of Soybean Flour (Glycine max L. Merrill) as a Food Supplement for Infants Sold in Daloa

2021 ◽  
pp. 24-30
Author(s):  
Kouassi Kra Athanase ◽  
Ouina Toualy Serge Thibaut ◽  
Voko Bi Rosin Don Rodrigue ◽  
Kouassi Kouassi Clément ◽  
Coulibaly Ibourahema ◽  
...  
Keyword(s):  
Microbiological Quality ◽  
Food Supplement ◽  
Physical Parameters ◽  
Microbiological Analysis ◽  
Soybean Flour ◽  
E Coli ◽  
Physico Chemical ◽  
Microbiological Criteria ◽  
Glycine Max L ◽  
Yeasts And Molds

The objective of this study is to assess the presence of harmful microorganisms and to characterize some physicochemical parameters in the soya flour sold in Daloa. To carry out the work, sixty (60) samples of soybean flour were collected by purchase in PMI (20), supermarkets (20) and in certain markets (20) made up of grains that will be transformed into flour according to the defined conditions. by ourselves. His samples will be transferred to the microbiology laboratory for analysis. A count to assess the microbiological quality was carried out. The assay of some chemical parameters and the determination of some physical parameters were performed. The different pH values ​​obtained are all alkaline. Microbiological analysis revealed compliance of average microbial loads of fungi (yeasts and molds) below 103 CFU / g and aerobic mesophilic bacteria below 105 CFU / g. On the other hand, the average microbial loads of total coliforms do not comply with the defined microbiological criteria. Furthermore, with regard to the potentially pathogenic germs in Bacillus cereus occurrences, there is no conformity of the average loads of the three types of flour. The defined criterion being 10 CFU / g. As for E. coli and S. aureus, only F1 flour complies with microbiological criteria. There is a presence of Salmonella in 60% of the samples of the F1 flour. Good practices should be observed in the processing of grains into flour in order to avoid possible contamination of the flour.

A Comparison of Different Chemical Sanitizers for Inactivating Escherichia coli O157:H7 and Listeria monocytogenes in Solution and on Apples, Lettuce, Strawberries, and Cantaloupe

2004 ◽  
Vol 67 (4) ◽  
pp. 721-731 ◽  
Author(s):  
STEPHANIE L. RODGERS ◽  
JERRY N. CASH ◽  
MOHAMMAD SIDDIQ ◽  
ELLIOT T. RYSER
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Chlorine Dioxide ◽  
Model System ◽  
Trisodium Phosphate ◽  
Escherichia Coli O157 ◽  
Peroxyacetic Acid ◽  
E Coli ◽  
Log Reduction ◽  
Yeasts And Molds

Ozone (3 ppm), chlorine dioxide (3 and 5 ppm), chlorinated trisodium phosphate (100- and 200-ppm chlorine), and peroxyacetic acid (80 ppm) were assessed for reduction of Escherichia coli O157:H7 and Listeria monocytogenes in an aqueous model system and on inoculated produce. Initially, sanitizer solutions were inoculated to contain approximately 106 CFU/ml of either pathogen, after which aliquots were removed at 15-s intervals over a period of 5 min and appropriately plated to determine log reduction times. Produce was dip inoculated to contain ~106 E. coli O157:H7 or L. monocytogenes CFU/g, held overnight, submerged in each sanitizer solution for up to 5 min, and then examined for survivors. In the model system study, both pathogens decreased >5 log following 2 to 5 min of exposure, with ozone being most effective (15 s), followed by chlorine dioxide (19 to 21 s), chlorinated trisodium phosphate (25 to 27 s), and peroxyacetic acid (70 to 75 s). On produce, ozone and chlorine dioxide (5 ppm) were most effective, reducing populations ~5.6 log, with chlorine dioxide (3 ppm) and chlorinated trisodium phosphate (200 ppm chlorine) resulting in maximum reductions of ~4.9 log. Peroxyacetic acid was the least effective sanitizer (~4.4-log reductions). After treatment, produce samples were stored at 4°C for 9 days and quantitatively examined for E. coli O157:H7, L. monocytogenes, mesophilic aerobic bacteria, yeasts, and molds. Populations of both pathogens remained relatively unchanged, whereas numbers of mesophilic bacteria increased 2 to 3 log during storage. Final mold and yeast populations were significantly higher than initial counts for chlorine dioxide- and ozone-treated produce. Using the nonextended triangle test, whole apples exposed to chlorinated trisodium phosphate (200 ppm chlorine) and shredded lettuce exposed to peroxyacetic acid were statistically different from the other treated samples.

scholarly journals Physical-Chemical and Microbiological Analysis of the Steaming Brine Used in the Fabrication of Pressed Cheeses

1970 ◽  
Vol 66 (2) ◽  
Author(s):  
Dorin ŢIBULCĂ ◽  
Aurora ŢIBULCĂ ◽  
Mirela JIMBOREAN ◽  
Cornel LASLO ◽  
Delia TRUŢĂ
Keyword(s):  
Salt Concentration ◽  
Coliform Bacteria ◽  
Microbiological Analysis ◽  
Salmonella Spp ◽  
E Coli ◽  
Milk Processing ◽  
Physical Chemical ◽  
Microbiological Aspects ◽  
Made In

The investigations had as aim to study the physical-chemical aspects (salt concentration and temperature) and microbiological aspects (TNG, coliform bacteria, E. coli, Stqfilococcus aureus c.p. and Salmonella spp.) of the steaming brine in the fabrication of the pressed cheeses Dalia, Rucăr, Penteleu. The investigations were made in five milk processing units in cheeses with steamed paste.

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