Incidence and Survival of Listeria monocytogenes in Ready-To-Eat Seafood Products

1997 ◽  
Vol 60 (4) ◽  
pp. 372-376 ◽  
Author(s):  
SUSAN A. MCCARTHY
Keyword(s):  
Listeria Monocytogenes ◽  
Storage Time ◽  
Storage Temperature ◽  
Storage Conditions ◽  
Plate Count ◽  
Standard Plate Count ◽  
Smoked Salmon ◽  
Standard Plate ◽  
Seafood Products ◽  
Survival And Growth

The effects of processing and postprocess storage conditions on the incidence and survival of Listeria monocytogenes on crawfish (Procambaris sp.), crabmeat (Callinectus sapidus), and smoked salmon (Salmo salar) were evaluated. L. monocytogenes was recovered from 3% of whole boiled market crawfish samples and 17% of frozen vacuum-packaged partially cooked crawfish tail meat, but not from boiled crabmeat or smoked salmon. Contamination was most likely due to postprocess handling as commonly used methods of cooking (5 min boil or 20 min steep) reduced L. monocytogenes to nondetectable levels in laboratory-contaminated crawfish. In postprocess storage temperature abuse studies, cooked whole crawfish were inoculated internally and externally with 3.0 log CFU of L. monocytogenes per g and incubated at 22 or 30°C for 6 h. The greatest increase in numbers of cells, 1.9 log CFU/g (determined by standard plate count), occurred at 30°C on externally contaminated crawfish. There was little change in numbers of L. monocytogenes during cold storage (6°C, 5 days; −20°C, 15 days). There was little change in cell numbers associated with products stored at 22 or −20°C. At 6°C, numbers of cells associated with crabmeat increased by 3.8 log MPN/g after 6 days; however, there was no increase in numbers of cells associated with salmon. The results show that the survival and growth characteristics of L. monocytogenes are dependent on storage time and temperature and the nature of the seafood product.

Effects of Irradiation on Bacterial Load and Listeria monocytogenes in Raw Chicken

1992 ◽  
Vol 55 (5) ◽  
pp. 389-391 ◽  
Author(s):  
YURI VARABIOFF ◽  
GREGORY E. MITCHELL ◽  
STEPHEN M. NOTTINGHAM
Keyword(s):  
Listeria Monocytogenes ◽  
Cold Storage ◽  
Bacterial Load ◽  
Storage Period ◽  
Plate Count ◽  
Standard Plate Count ◽  
Standard Plate ◽  
Effects Of Irradiation On

After irradiation of chickens to a dose of 2.5 kGy, the decrease in the standard plate count (SPC) was similar in air and in vacuum-packaged chickens. During storage at 4°C for 15 d, the SPC increased progressively in both types of packaged chickens. At the end of the storage period, the SPC was higher in air-packaged chicken than in vacuum-packaged chickens. In irradiated chickens, Listeria monocytogenes was only recovered from the vacuum-packaged chickens after 7 d cold storage. In unirradiated chickens, L. monocytogenes proliferated similarly in both air- and vacuum-packaged chickens.

Effects of packaging on the quality parameters of mustard ilish (Tanualosa ilisha) at room temperature

2020 ◽  
Vol 32 (1) ◽  
pp. 83-94
Author(s):  
F.H. SHIKHA ◽  
M.I. HOSSAIN ◽  
S. MAHMUDA
Keyword(s):  
Room Temperature ◽  
Storage Time ◽  
Ph Value ◽  
Storage Period ◽  
Quality Parameters ◽  
Plate Count ◽  
Standard Plate Count ◽  
Percent Moisture ◽  
Standard Plate ◽  
Raw Fish

The experiment was carried out to prepare mustard ilish at the laboratory and observe the effects ofpackaging on the quality parameters of the product at room temperature (28°C to 32°C). Biochemical andmicrobiological changes in mustard ilish prepared from Hilsa shad (Tanualosa ilisha) were determined. It wasobserved that percent moisture, protein, lipid, ash content and pH value in mustard ilish decreased afterpreparation of the product than those values obtained for raw fish. In quality parameters study, at roomtemperature (28°C to 32°C), percent moisture, and ash contents increased throughout the storage period, butprotein and lipid contents decreased. The TVB-N, peroxide value and standard plate count (SPC) of bacteriaincreased with the progress of storage time but the rate of increment was comparatively slower in sealed andvacuum sealed packs than the rate observed for non-sealed pack. Therefore, on the basis of above mentionedpoints, the present study could be concluded as-though mustard ilish remain in acceptable condition for ashort time at room temperature (28°C to 32°C) but packaging has some effect on the extension of shelf life ofthe product.

Bacteriological Quality of Fresh Seafood Products from Seattle Retail Markets

1983 ◽  
Vol 46 (10) ◽  
pp. 901-909 ◽  
Author(s):  
CARLOS ABEYTA
Keyword(s):  
Puget Sound ◽  
Microbiological Quality ◽  
Mean Value ◽  
Plate Count ◽  
Arithmetic Means ◽  
Retail Markets ◽  
Standard Plate Count ◽  
Standard Plate ◽  
Seafood Products

A microbiological survey of 287 (fresh) seafood products from Puget Sound retail markets was conducted over a period of 1 year. The microbiological quality of fresh seafood was high, with only 2.1 % of the samples exceeding the maximum limit for acceptability as suggested by the International Commission on Microbiological Specifications for Foods (ICMSF). The overall microbiological data of positive units given as arithmetic means were: coliforms MPN/g, 199; Escherichia coli MPN/g, 21; coagulase-positive Staphylococcus aureus MPN/g, 66; enterococci/g, 9121; Clostridium perfringens/g, 18; Bacillus cereus/g, 100; and Vibrio parahaemolyticus MPN/g, 3.7. The standard plate count means 1.0 × 103 to 2.5 × 107 colony-forming units (CFU)/g, giving a mean value of 2.0 × 105 CFU/g. The percentages of seafood samples positive for pathogens were S. aureus, 37.6; Yersinia enterocolitica, 3.8; V. parahaemolyticus, 2.8; C. perfringens, 2.4; and B. cereus, 0.7. Vibrio cholerae, Clostridium botulinum, Salmonella and Shigella species were not isolated.

KEEPING QUALITY OF MILK EXPOSED TO HIGH TEMPERATURE AS EXPERIENCED DURING TRANSPORT IN AUTOMOBILES1

1972 ◽  
Vol 35 (10) ◽  
pp. 588-590
Author(s):  
K. L. Smith ◽  
L. E. Mull ◽  
C. B. Lane ◽  
A. J. Baggott
Keyword(s):  
High Temperature ◽  
Storage Temperature ◽  
Storage Period ◽  
Plate Count ◽  
Lag Phase ◽  
Standard Plate Count ◽  
Warm Weather ◽  
Standard Plate ◽  
Quality Of Milk

To simulate conditions encountered in automobiles during warm weather in Florida, half-gallon cartons of milk, after tempering at 39 F, were exposed to 120 F for 0, 30, 60 or 90 min, after which milks were 39, 64, 78, and 91 F, respectively. All samples were then held at 39 F throughout the remainder of the study. The standard plate count was significantly higher on samples exposed to 120 F for 60–90 min than on those exposed for the shorter time. A taste panel detected flavor differences among samples of milk receiving the different heat exposures. The shelf-life of fluid milk was determined by the number of bacteria present in the sample at the commencement of the storage period, the length of the lag phase of growth, the rate of bacterial growth at the storage temperature used, and finally the type of microorganism present. If milk is to be exposed to high temperature in an automobile for more than 30 min, it should be held in an insulated container until it can be placed in the home refrigerator.

Effect of Inoculum Preparation Procedure and Storage Time and Temperature on the Fate of Listeria monocytogenes on Inoculated Salami

2008 ◽  
Vol 71 (3) ◽  
pp. 494-501 ◽  
Author(s):  
CATHERINE A. SIMPSON ◽  
IFIGENIA GEORNARAS ◽  
YOHAN YOON ◽  
JOHN A. SCANGA ◽  
PATRICIA A. KENDALL ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Yeast Extract ◽  
Storage Time ◽  
Storage Temperature ◽  
Storage Conditions ◽  
Three Samples ◽  
Fermented Sausages ◽  
Inoculum Preparation ◽  
And Storage ◽  
Inoculum Type

Although dry/semidry fermented sausages are characterized as being of low-to-moderate risk for human listeriosis on a per-serving and per-annum basis, data are lacking relative to the fate of postprocessing Listeria monocytogenes contamination during storage of such products. This study evaluated the effect of inoculum preparation and storage conditions on the fate of L. monocytogenes on vacuum-packaged salami. Commercially produced salami was sliced and inoculated (4 ± 1.3 log CFU/cm2) with one of four types of inocula. All inocula consisted of the same 10-strain L. monocytogenes composite, cultivated as individual strains prior to mixing for inoculation. Active cultures of individual strains were prepared (30°C, 24 h) in either tryptic soy broth (containing 0.25% glucose) plus 0.6% yeast extract (TSBYE), tryptic soy broth without glucose plus 0.6% yeast extract (TSBYE–G), TSBYE–G plus 1% glucose (TSBYE+G), or in TSBYE, and then habituated (7°C, 72 h) in sterile salami homogenate (10% [wt/wt] with distilled water). Inoculated salami slices were vacuum packaged, stored at 4, 12, or 25°C, and analyzed (three samples per treatment in each of two replicates) periodically for surviving bacterial counts. In general, pathogen levels decreased during storage and reached levels below the detection limit (−0.4 log CFU/cm2) between 27 and 90 days of storage, depending on temperature of storage and inoculum type. Death rates (log CFU/cm2/day) were found to increase as storage temperature increased, with the exception of the acid-adapted (TSBYE+G) cells, which decreased more rapidly at 4°C than at 12 or 25°C. The habituated inoculum was inactivated at a faster rate than other inocula at 12 and 25°C, but performed similarly to nonadapted (TSBYE–G) and partially acid-adapted (TSBYE) inocula at 4°C. These data may be used to supplement existing information for use in future risk assessments.

Pyruvate as an Indicator of Quality in Grading Nonfat Dry Milk1

1982 ◽  
Vol 45 (6) ◽  
pp. 561-565 ◽  
Author(s):  
R. T. MARSHALL ◽  
Y. H. LEE ◽  
B. L. O'BRIEN ◽  
W. A. MOATS
Keyword(s):  
Geometric Mean ◽  
Regression Line ◽  
Skim Milk ◽  
Plate Count ◽  
Department Of Agriculture ◽  
Standard Plate Count ◽  
Geometric Average ◽  
Dry Milk ◽  
Standard Plate ◽  
Microscopic Count

Samples of skim milk and nonfat dry milk (NDM) made from it were collected, paired and tested for pyruvate concentration, [P], and Direct Microscopic count (DMC). The skim milk was tested for Standard Plate Count (SPC) and Psychrotrophic Plate Count (PPC). The geometric average DMC of skim milk was more than three times higher than that of the paired NDM samples. However, [P] of NDM was not significantly different from that of the skim milk. Although [P] of skim milk was poorly correlated with SPC and PPC, r = .31 and .26, respectively, it was relatively well correlated with DMC, r = .64. Data were widely dispersed around the regression line when [P] was ≤ 4.0 mg/L. However, [P] increased rapidly when DMCs were > 106/ml. A limit of 10 mg/L of [P] in NDM reconstituted 1:9 was chosen to represent the current U.S. Department of Agriculture Standard for DMC in NDM. This limit failed to classify about 10% of the samples correctly, assuming that each geometric mean DMC was correct. However, the probability that samples meeting the DMC standard would be rejected by the pyruvate test was quite low and the probability was moderate that samples which would be acceptable by the pyruvate test would be rejected by the DMC. For the latter, 28% of the samples having DMCs of ≥ 107/ml contained < 10 mg/L of pyruvate. No sample having ≥ 10 mg/L of pyruvate had a DMC of ≤ 107/ml. Pyruvate concentration in NDM did not change during storage at 5 or 32°C for 90 days.

Bioluminescence: A Rapid Indicator of Escherichia Coli O157:H7 in Selected Yogurt and Cheese Varieties

1997 ◽  
Vol 60 (8) ◽  
pp. 891-897 ◽  
Author(s):  
L. M. HUDSON ◽  
J. CHEN ◽  
A. R. HILL ◽  
M. W. GRIFFITHS
Keyword(s):  
Escherichia Coli ◽  
Enterohemorrhagic Escherichia Coli ◽  
Cottage Cheese ◽  
Plate Count ◽  
Escherichia Coli O157 ◽  
Potential Hazard ◽  
Growth And Survival ◽  
E Coli ◽  
Standard Plate Count ◽  
Standard Plate

Outbreaks of enterohemorrhagic Escherichia coli O157:H7 have been commonly associated with products derived from ground beef, but recently the organism has been implicated as the causative agent in outbreaks involving yogurt and cheese. This finding has raised concern about the potential for its growth and survival in fermented dairy products. A bioluminescent strain of E. coli O157:H7 was used to determine postprocessing survival in yogurt with live cultures at pH 4.17, 4.39, and 4.47 stored at 4 and 10°C. In addition, survival of E. coli O157:H7 was monitored during the manufacture of Cottage, Colby, Romano, and Feta cheeses. Results indicated survival for 8 and 5 days at 4 and 10°C respectively in yogurt at pH 4.17, 17 and 15 days at 4 and 10°C respectively in yogurt at pH 4.39, and 17days at both 4 and 10°C in yogurt at pH 4.47. E. coli O157:H7 did not survive cooking procedures at 56°C in Cottage cheese. However, the pathogen survived for 27, 30, and 27 days in Colby, Romano, and Feta cheeses respectively. A high correlation of r2 > 0.89 was obtained between counts of bioluminescenct colonies and standard plate count for all yogurt and cheese varieties, indicating that bioluminescence was a sensitive and rapid indicator of cellular viability for E. coli O157:H7. Survival of the pathogen, as indicated by this method, is possible in highly acidic environments even at refrigeration temperatures. This poses a potential hazard should postprocessing contamination occur.

Evaluation of the 3M Dry Medium Culture Plate (Petrifilm™ SM) Method for Determining Numbers of Bacteria in Raw Milk1

1984 ◽  
Vol 47 (10) ◽  
pp. 753-755 ◽  
Author(s):  
R. E. GINN ◽  
V. S. PACKARD ◽  
T. L. FOX
Keyword(s):  
Cold Water ◽  
Correlation Coefficients ◽  
Raw Milk ◽  
Water Soluble ◽  
Gelling Agent ◽  
Plate Count ◽  
Suitable Alternative ◽  
Standard Plate Count ◽  
Standard Plate ◽  
Indicator Dye

The 3M Company has developed a sample-ready system (Petrifilm ™ SM) for enumerating bacteria in milk and other food products. The testing unit consists of Standard Methods culture medium coated onto a base film and overlaid with a second film coated with a cold-water-soluble gelling agent and tetrazolium indicator dye. As such, the system is ready to accept samples of product. A pipette or 0.001-ml plate loop continuous pipetting syringe can be used for applying samples. In this study, both methods of sample addition were used and results compared with those of the Standard Plate Count (SPC) and standard Plate Loop (PL) methods for determining bacteria numbers in raw milk. In total, 108 samples were analyzed in duplicate by each of the four methods. The correlation coefficients (r) between the 3M-SPC and SPC, 3M-PL and PL, 3M-PL and SPC and PL and SPC were 0.946, 0.935, 0.941, and 0.974, respectively. Repeatability, as measured by mean log10 variance for duplicate determinations, was essentially the same for the four methods, and in all instances less than 0.005. The mean log10 differences between the SPC and 3M-SPC, and SPC and 3M-PL were, respectively, −0.177 and −0.168. The preceding statistical criteria suggest the Petrifilm™ SM method to be a suitable alternative to the SPC or the PL procedure.

scholarly journals Comparison of Probiotic Isolate Growth in Natural Culture with Various Carbon Sources

2021 ◽  
Vol 6 (2) ◽  
pp. 103-107
Author(s):  
Sitti Nur Ilmiah ◽  
Zaraswati Dwyana ◽  
Asadi Abdullah
Keyword(s):  
Carbon Sources ◽  
Plate Count ◽  
Standard Plate Count ◽  
Standard Plate

Probiotik merupakan mikroba hidup yang memberikan pengaruh menguntungkan pada inang karena dapat menyeimbangkan mikroba yang ada dalam saluran pencernaan menjadi meningkat. Pemanfaatan tersebut dapat memberikan pengaruh positif dan kesehatan bagi inang sehingga sangat baik untuk diaplikasikan. Pemanfaatan bahan alami dapat menekan biaya media tumbuh sehingga perlu penggantian media sintetik dengan media alami karena memiliki harga yang relatif lebih murah tetapi mengandung nutrien penting bagi pertumbuhan mikroba. Tujuan penelitian ini adalah untuk mengetahui pertumbuhan isolat probiotik berdasarkan lama waktu kutur dalam media alami yang mengandung sumber karbon berbeda. Pertumbuhan isolat probiotik dalam berbagai sumber karbon dilakukan melalui metode Standard Plate Count (SPC). Melalui metode SPC didapatkan jumlah koloni isolat G dari masing-masing media berupa kanji, sagu, dan dedak yaitu 2,3 x 108 Cfu/mL, 6,4 x 106 Cfu/mL, dan 4,3 x 106 Cfu/mL selama 48 jam; 2,6 x 108 Cfu/mL, 1,6 x 108 Cfu/mL, dan 1,0 x 108 Cfu/mL selama 96 jam; 4,6 x 108 Cfu/mL, 1,8 x 108 Cfu/mL, dan 1,2 x 108 Cfu/mL selama 144 jam. Hasil yang didapatkan menunjukkan bahwa isolat G mampu ditumbuhkan dalam media alami berupa kanji, sagu dan dedak.

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