Destruction of Escherichia coli and Salmonella typhimurium in Microwave-cooked Soups

1975 ◽  
Vol 38 (1) ◽  
pp. 8-15 ◽  
Author(s):  
K. A. CULKIN ◽  
DANIEL Y. C. FUNG
Keyword(s):  
Escherichia Coli ◽  
Salmonella Typhimurium ◽  
Exposure Time ◽  
Plate Count ◽  
Temperature Sensitive ◽  
Consistent Finding ◽  
Microwave Exposure ◽  
Standard Plate Count ◽  
Standard Plate

Single serving (i.e. 200 ml) portions of tomato soup, vegetable soup, and broth inoculated with Escherichia coli or Salmonella typhimurium at about 107 organisms/ml were exposed to 915 MHz microwaves. After various timed exposures the temperature of the top, middle, and bottom regions as indicated by changes in previously positioned assemblies of temperature sensitive paper strips were noted and aliquots were removed from the same regions for standard plate count determination of survivors. For any given exposure time, the temperature of the middle region was warmest; that of the bottom, intermediate; and the temperature of the top, coolest. Despite the relative temperatures of the regions, however, the consistent finding was that, for any exposure time, the closer the sampled organisms were to the top, the lower their level of survival. In terms of temperature, it was noted that organisms in the top had declined to a given level of survival at a temperature lower than the temperature corresponding to the same survival level in the middle or bottom soup regions. These data suggest that the heat generated during the microwave exposure alone is inadequate to fully account for the nature of the lethal effects of microwaves for microorganisms.

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.

Microbiological Quality of Shellfish-Growing Waters in Chesapeake Bay

1994 ◽  
Vol 57 (3) ◽  
pp. 229-234 ◽  
Author(s):  
TUU-JYI CHAI ◽  
TZYY-JAN HAN ◽  
RALPH R. COCKEY
Keyword(s):  
Escherichia Coli ◽  
Chesapeake Bay ◽  
Water Samples ◽  
Microbiological Quality ◽  
Geographic Area ◽  
Water Area ◽  
Fecal Coliforms ◽  
Plate Count ◽  
Standard Plate Count ◽  
Standard Plate

A total of 338 water samples were collected at 20 stations from three geographically shellfish-growing areas in Chesapeake Bay from May to September 1989. Samples were examined for standard plate count, total coliforms, fecal coliforms, Escherichia coli and coliphages. Salinity, dissolved oxygen and temperature varied slightly with the depth, season, and geographic area of water samples. The geometric means of standard plate count for the three areas were 135, 355 and 275/ml, respectively. The range of means of fecal coliform for these areas was from <3 to 93/100 mi. Escherichia coli counts were also low with a range of <3 to 93/100 mi and a mean of < 3/100 mi. The growing water area adjacent to cropland was found to have higher bacterial counts than those of the other two areas. Levels of male-specific phages were very low. Results indicate that shellfish-growing waters in all three areas were of satisfactory bacteriological quality.

Microbial Flora of Preseasoned Comminuted Turkey Meat

1977 ◽  
Vol 40 (5) ◽  
pp. 322-324 ◽  
Author(s):  
LINDA S. GUTHERTZ ◽  
JOHN T. FRUIN ◽  
JAMES L. FOWLER
Keyword(s):  
Escherichia Coli ◽  
Microbial Contamination ◽  
Microbial Flora ◽  
Plate Count ◽  
Gram Positive ◽  
Gram Negative ◽  
Turkey Meat ◽  
Standard Plate Count ◽  
Standard Plate

Preseasoned comminuted turkey meat, prepared at the retail level, was examined and revealed the following levels of microbial contamination per gram: mean standard plate count 2.2 × 108, mean coliform plate count 2.0 × 105, Escherichia coli count 8.7. Gram-positive and gram-negative microbial flora were isolated and identified.

EFFECT OF TEMPERATURE AND TIME OF PLATE INCUBATION ON THE ENUMERATION OF PASTEURIZATION-RESISTANT BACTERIA IN MILK1

1963 ◽  
Vol 26 (11) ◽  
pp. 357-363 ◽  
Author(s):  
W. R. Thomas ◽  
G. W. Reinbold ◽  
F. E. Nelson
Keyword(s):  
Incubation Temperature ◽  
Bacterial Count ◽  
Raw Milk ◽  
Effect Of Temperature ◽  
Plate Count ◽  
Resistant Bacteria ◽  
Pasteurized Milk ◽  
Standard Plate Count ◽  
Standard Plate

This study was undertaken to determine the effect of temperature and time of plate incubation upon the count of thermoduric bacteria in milk. Specific types of thermoduric bacteria in pure culture, as well as those present in the mixed flora of commercial milk samples, were enumerated. Plate incubation at 28 C for 4 days was the temperature-time combination that produced the highest thermoduric bacterial count with laboratory-pasteurized milk. Incubation at 21, 32 or 35 C gave lower counts. Thermoduric bacteria subjected to pasteurization were more exacting in their growth temperature requirements than were unheated bacteria. Cultures of Arthrobacter sp., Micrococcus varians and Streptococcus sp. grew over a much wider temperature range before laboratory pasteurization than after the heat treatment. The incubation temperature and time currently recommended for the standard plate count, while presumably adequate for the enumeration of bacteria in raw milk, may not be equally satisfactory for the determination of the maximum viable bacterial population of pasteurized milk.

Correlation study between standard plate count and flow cytometry for determination of raw milk total bacterial count

2007 ◽  
Vol 60 (1) ◽  
pp. 44-48 ◽  
Author(s):  
LAERTE DAGHER CASSOLI ◽  
PAULO FERNANDO MACHADO ◽  
ANA CAROLINA DE OLIVEIRA RODRIGUES ◽  
ARLEI COLDEBELLA
Keyword(s):  
Flow Cytometry ◽  
Bacterial Count ◽  
Raw Milk ◽  
Correlation Study ◽  
Plate Count ◽  
Total Bacterial Count ◽  
Standard Plate Count ◽  
Standard Plate

EFFECT OF THE TYPE OF BACTERIOLOGICAL PEPTONE IN THE PLATING MEDIUM UPON THE ENUMERATION OF PASTEURIZATION-RESISTANT BACTERIA IN MILK1

1966 ◽  
Vol 29 (6) ◽  
pp. 182-186 ◽  
Author(s):  
W. R. Thomas ◽  
G. W. Reinbold ◽  
F. E. Nelson
Keyword(s):  
Raw Milk ◽  
Plate Count ◽  
Colony Development ◽  
Resistant Bacteria ◽  
Pasteurized Milk ◽  
Standard Plate Count ◽  
Standard Plate ◽  
Viable Bacteria

Summary Various bacteriological, peptones were studied as to effects on enumeration of pasteurization-resistant bacteria in milk. No appreciable differences were observed in colony counts of unheated cultures of thermoduric Micrococcus varians and Arthrobacter and Streptococcus sp. when plated with media containing different peptones. After laboratory pasteurization, colony counts differed substantially. Usually, media producing the highest counts yielded the largest and most easily discernible colonies. Bacto-Tryptone was deficient for colony development of thermoduric streptococci. Results indicate that, although seemingly adequate for enumeration in raw milk, the bacteriological peptone currently recommended for the standard plate count may not be satisfactory for the determination of the maximum viable bacteria population of pasteurized milk.

EFFECT OF pH OF PLATING MEDIUM ON ENUMERATION OF PASTEURIZATION-RESISTANT BACTERIA IN MILK1

1966 ◽  
Vol 29 (5) ◽  
pp. 156-160 ◽  
Author(s):  
W. R. Thomas ◽  
G. W. Reinbold ◽  
F. E. Nelson
Keyword(s):  
Heat Treatment ◽  
Raw Milk ◽  
Plate Count ◽  
Resistant Bacteria ◽  
Medium Ph ◽  
Standard Plate Count ◽  
Standard Plate ◽  
Pure Cultures ◽  
Viable Bacteria

Summary Plating media of different pH were studied as to effects on enumeration of pasteurization-resistant bacteria in milk. After heat treatment, thermoduric bacteria were more tolerant of pH levels above rather than below 7, and maximum mean thermoduric counts were obtained at pH 7.5. There were some exceptions, but usually the pH levels that yielded the highest counts also produced the largest and most easily discernible colonies. Pure cultures of thermoduric bacteria grew over a much wider range of pH before than they did after laboratory pasteurization. Results indicate that, although seemingly adequate for enumeration in raw milk, the medium pH currently recommended for the standard plate count may not be satisfactory for the determination of the maximum viable bacteria population of pasteurized milk.

scholarly journals System Impressed Current Anti Fouling (ICAF) Against Micro Fouling (Bacteria) on Ship’s Cooling System

2018 ◽  
Vol 177 ◽  
pp. 01013 ◽  
Author(s):  
Herman Pratikno ◽  
Harmin Sulistiyaning Titah ◽  
Muhammad Danesto Rizky Mauludin
Keyword(s):  
Pseudomonas Fluorescens ◽  
Marine Environment ◽  
Cooling System ◽  
Electrical Current ◽  
Plate Count ◽  
Standard Plate Count ◽  
Current Variation ◽  
Standard Plate ◽  
Impressed Current

Bio-fouling is the attachment and accumulation of an organism or micro-organism to a material. Bio-fouling is one of the causes of declining performance and quality in a system of structures, especially structures that have a direct relationship with the waters where the bio-fouling live and move. The research was conducting using a simple circuit that represents Impressed Current Anti Fouling (ICAF) system which is generally located on the cooling of the ship against micro-fouling or bacteria. Species of bacteria (Pseudomonas fluorescens) in the marine environment was used as an object. The bacteria were introduced into the reactor containing the cathode and anode of this simple system, with inputs of experimental time variation of 3, 5 and 7 minutes and electrical current variation of 0.1, 0.3, and 0.5 Ampere. The determination of bacteria population was conducted using standard plate count methods. The results showed that ICAF system can reduce the bacteria populations. The largest percentage of Pseudomonas fluorescens reduction was 99.9%, while the smallest percentage showed 98.5% percentage. In conclusion, the simple of ICAF system can be used to prevent appearance of micro-fouling in marine environment.

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