Survival of Salmonella and Escherichia coli O157:H7 in Chorizos

2005 ◽  
Vol 68 (10) ◽  
pp. 2039-2046 ◽  
Author(s):  
CARRIE M. HEW ◽  
MAHA N. HAJMEER ◽  
THOMAS B. FARVER ◽  
JAMES M. GLOVER ◽  
DEAN O. CLIVER
Keyword(s):  
Escherichia Coli ◽  
Sampling Period ◽  
Storage Condition ◽  
Storage Conditions ◽  
Scientific Basis ◽  
Escherichia Coli O157 ◽  
Initial Water ◽  
Initial Ph ◽  
Forced Air ◽  
Air Circulation

Mexican-style raw meat sausages (chorizos) are not regulated in California when they are produced in small ethnic food markets. These sausages are sold uncooked, but their formulation imparts a color that may lead the consumer to assume that they are already cooked, and thus the chorizos may sometimes be eaten without proper cooking. If pathogens are present in such cases, illness may result. Survival of Salmonella and Escherichia coli O157:H7 in chorizos was evaluated under different storage conditions selected based on an initial survey of uninspected chorizos in California. Chorizos were formulated with five different initial water activity (aw) values (0.85, 0.90, 0.93, 0.95, and 0.97), stored under four conditions (refrigeration at 6 to 8°C, room temperature at 24 to 26°C, under a hood at 24 to 26°C with forced air circulation, and incubation at 30 to 31°C with convective air circulation), and sampled after 1, 2, 4, and 7 days. The initial pH was 4.8 and remained near 5.0 from day 1 of the sampling period. Two separate studies of packs inoculated with five-strain cocktails of Salmonella and of E. coli O157:H7 were performed twice for each initial aw. The three lowest aw values (0.85, 0.90, and 0.93) and the incubation and hood storage conditions were more effective (P ≤ 0.05) at reducing the target pathogen levels in chorizos than were the two highest aw values (0.95 and 0.97) and the refrigeration storage condition, regardless of storage time. These results provide a scientific basis for guidelines given to producers of uninspected chorizo and should reduce the probability of foodborne illness associated with these products.

Survival of Listeria monocytogenes in Experimental Chorizos

2005 ◽  
Vol 68 (2) ◽  
pp. 324-330 ◽  
Author(s):  
CARRIE M. HEW ◽  
MAHA N. HAJMEER ◽  
THOMAS B. FARVER ◽  
JAMES M. GLOVER ◽  
DEAN O. CLIVER
Keyword(s):  
Listeria Monocytogenes ◽  
Sampling Period ◽  
Storage Condition ◽  
Storage Conditions ◽  
Scientific Basis ◽  
Initial Water ◽  
Initial Ph ◽  
Forced Air ◽  
Initial Survey ◽  
Air Circulation

Chorizos—Mexican-style raw-meat sausages—are a concern in California because their production in small ethnic food markets is unregulated. Their formulation may cause them to appear cooked to the consumer, who may eat the raw sausage without prior proper cooking. Bacterial pathogens in such products may cause illness or even death. Survivability of Listeria monocytogenes in chorizos was evaluated under different storage conditions selected on the basis of an initial survey of uninspected chorizos in California. Sausages were formulated to five different initial water activity (aw) levels (0.85, 0.90, 0.93, 0.95, 0.97), stored under four conditions (refrigeration, “Ref,” 6 to 8°C under convective air circulation; room temperature, “RT,” 24 to 26°C under convective air circulation; hood, “Hd,” 24 to 26°C under forced air circulation; and incubation, “Inc,” 30 to 31°C under convective air circulation), and sampled after 1, 2, 4, and 7 days. The initial pH was 4.8 and remained near 5.0 from day 1 of the sampling period. An inoculated-pack study using a five-strain cocktail of L. monocytogenes was performed twice for each initial aw. Results indicated that the three lowest initial aw levels (0.85, 0.90, 0.93) and the Hd and Inc storage conditions were more effective (P ≤ 0.05) at reducing L. monocytogenes levels in chorizos than the two highest initial aw levels (0.95 and 0.97) and the Ref storage condition, irrespective of storage time. These results can provide a scientific basis for guidelines given to uninspected chorizo producers in California and reduce the risk of foodborne illness.

24-Hour Presumptive Enumeration of Escherichia coli O157:H7 in Foods by Using the ISO-GRID® Method with SD-39 Agar

1997 ◽  
Vol 60 (8) ◽  
pp. 883-890 ◽  
Author(s):  
PHYLLIS ENTIS ◽  
IRINA LERNER
Keyword(s):  
Escherichia Coli ◽  
Membrane Filter ◽  
Storage Conditions ◽  
Food Storage ◽  
Most Probable Number ◽  
Escherichia Coli O157 ◽  
Filtration Method ◽  
Probable Number ◽  
Direct Filtration ◽  
The Comparative Study

Two 24-hour presumptive enumeration methods for Escherichia coli O157:H7 organisms based on the hydrophobic grid membrane filter (ISO-GRID) and using SD-39 agar, a new selective and differential culture medium, were developed and compared to a 3-tube MPN (most probable number) method using modified tryptone soy broth enrichment. The comparative study comprised 22 combinations of storage conditions and food products, including a variety of raw and cooked meats and several dairy products. The ISO-GRID direct filtration method produced counts which were equivalent to or significantly higher than the 3-tube MPN method for all food-storage combinations except for frozen pasteurized whole egg. The ISO-GRID resuscitation method produced counts equivalent to the 3-tube MPN method for the frozen egg.

Survival of Escherichia coli O157:H7 and Campylobacter jejuni in Bottled Purified Drinking Water under Different Storage Conditions

2011 ◽  
Vol 74 (2) ◽  
pp. 254-260 ◽  
Author(s):  
HAMZAH M. AL-QADIRI ◽  
XIAONAN LU ◽  
NIVIN I. AL-ALAMI ◽  
BARBARA A. RASCO
Keyword(s):  
Escherichia Coli ◽  
Drinking Water ◽  
Campylobacter Jejuni ◽  
Culture Media ◽  
False Negative ◽  
Storage Conditions ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Log Reduction ◽  
Negative Results

Survival of Escherichia coli O157:H7 and Campylobacter jejuni that were separately inoculated into bottled purified drinking water was investigated during storage at 22, 4, and −18°C for 5, 7, and 2 days, respectively. Two inoculation levels were used, 1 and 10 CFU/ml (102 and 103 CFU/100 ml). In samples inoculated with 102 CFU/100 ml, C. jejuni was not detectable (>2-log reduction) after storage under the conditions specified above. E. coli O157:H7 was detected on nonselective and selective media at log reductions of 1.08 to 1.25 after storage at 22°C, 1.19 to 1.56 after storage at 4°C, and 1.54 to 1.98 after storage at −18°C. When the higher inoculation level of 103 CFU/100 ml was used, C. jejuni was able to survive at 22 and 4°C, with 2.25- and 2.17-log reductions, respectively, observed on nonselective media. At these higher inoculation levels, E. coli O157:H7 was detectable at 22, 4, and −18°C, with log reductions of 0.76, 0.97, and 1.21, respectively, achieved on nonselective media. Additionally, E. coli O157:H7 showed significant differences in culturability (P < 0.05) on the nonselective and selective culture media under the different storage conditions, with storage at −18°C for 2 days being the treatment most inhibiting. The percentage of sublethal injury of E. coli O157:H7 ranged from ~33 to 75%, indicating that microbial examination of bottled water must be done carefully, otherwise false-negative results or underestimation of bacterial numbers could pose a health risk when low levels of pathogens are present.

Fate of Escherichia coli O157:H7 and Salmonella on Whole Strawberries and Blueberries of Two Maturities under Different Storage Conditions

2014 ◽  
Vol 77 (7) ◽  
pp. 1093-1101 ◽  
Author(s):  
THAO P. NGUYEN ◽  
LORETTA M. FRIEDRICH ◽  
MICHELLE D. DANYLUK
Keyword(s):  
Escherichia Coli ◽  
Storage Conditions ◽  
Escherichia Coli O157 ◽  
Atmospheric Conditions ◽  
Population Declines ◽  
Selective Media ◽  
E Coli ◽  
Modified Atmospheres ◽  
Retail Display ◽  
Storage Temperatures

Strawberries and blueberries harvested at or near full-ripe maturity tend to be less firm and more susceptible to bruising during harvest and transport. The objective of this research was to determine the fate of Escherichia coli O157:H7 and Salmonella on bruised and intact surfaces of whole strawberries and blueberries at shipping (2°C) and retail display (15.5°C) temperatures. Strawberries and blueberries were either purchased from a supermarket or were harvested immediately prior to use; they were bruised using established protocols, were spot inoculated, and were incubated at 2 and 15.5°C. Strawberries, subjected to modified atmospheres, were further transferred to bags and were sealed in with an initial atmosphere of ca. 10% CO2 and 5% O2. Strawberries were sampled at 0, 2, 5, and 24 h and on days 3 and 7; blueberries were sampled on days 0, 1, 3, and 7. After stomaching, samples were enumerated on nonselective and selective media, and populations were recorded as log CFU per berry. At both storage temperatures, population declines for both E. coli O157:H7 and Salmonella were seen under all conditions for strawberries. At 2 ± 2°C, E. coli O157:H7 and Salmonella populations on blueberries declined over 7 days under all conditions. At 15.5 ± 2°C, E. coli O157:H7 populations declined; however, Salmonella populations initially declined but increased to populations near or above initial populations over 7 days on blueberries. No overall significant differences were observed between bruised and intact treatments or between the two maturity levels for strawberries and blueberries. Modified atmospheric conditions did not affect the behavior of E. coli O157:H7 and Salmonella on strawberries at both temperatures. This research indicates that E. coli O157:H7 and Salmonella do not grow on strawberries at shipping or retail display temperatures, even when they are harvested at a maturity prone to bruising; however, Salmonella growth may occur on bruised full ripe blueberries under retail display temperatures.

Prior Storage Conditions Influence the Destruction of Escherichia coli O157:H7 during Heating of Apple Cider and Juice

1998 ◽  
Vol 61 (4) ◽  
pp. 390-394 ◽  
Author(s):  
STEVEN C. INGHAM ◽  
HEIDI E. ULJAS
Keyword(s):  
Escherichia Coli ◽  
Apple Juice ◽  
Storage Conditions ◽  
Escherichia Coli O157 ◽  
Strain Atcc ◽  
Linear Portion ◽  
Apple Cider ◽  
D Values ◽  
Short Time ◽  
Survivor Curve

In apple beverage manufacture, cider and juice may be stored for a short time prior to pasteurization. Storage time and temperature may affect the subsequent thermotolerance of bacteria in these beverages. This study examined whether prior storage in pH 3.4 apple cider or apple juice affected the thermotolerance of two Escherichia coli O157:H7 strains in the same beverages at 61°C. Both strains exhibited biphasic survivor curves. Strain ATCC 43894 was consistently more thermotolerant than strain ATCC 43889, with 33 to 153% greater D values derived from the linear portion of each survivor curve. Prior storage at 21°C for 2 or 6 h hastened thermal destruction of both strains in apple cider, but not to a statistically significant extent. In apple juice, prior storage at 21 °C for 2 h significantly decreased thermotolerance of strain ATCC 43889, but not of strain ATCC 43894. During 6 h of storage in 21°C apple juice, populations of strains ATCC 43889 and 43894 decreased by 2.1 and 0.5 log10 CFU/ml, respectively, and died rapidly during subsequent heating. Prior storage in apple juice at 4°C for 24 h significantly decreased thermotolerance of both strains, but this effect was not seen after 2 h of storage at 4°C. Experiments with filtered apple cider showed that presence of Alterable pulp enhanced the thermotolerance of both strains. These results show that short-term (≤6 h) room temperature storage of pH 3.4 apple cider and apple juice may enhance the lethality of subsequent pasteurization.

Real-Time Bioluminescence Analysis of Escherichia coli O157:H7 Survival on Livestock Meats Stored Fresh, Cold, or Frozen

2018 ◽  
Vol 81 (11) ◽  
pp. 1906-1912 ◽  
Author(s):  
SEONG B. PARK ◽  
SHECOYA B. WHITE ◽  
CHRISTY S. STEADMAN ◽  
CLAY A. CAVINDER ◽  
SCOTT T. WILLARD ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Real Time ◽  
Bacterial Growth ◽  
Room Temperature ◽  
Storage Conditions ◽  
Escherichia Coli O157 ◽  
Production Environment ◽  
Real Time Monitoring ◽  
E Coli ◽  
C Storage

ABSTRACT Foodborne bacteria such as Escherichia coli O157:H7 can cause severe hemorrhagic colitis in humans following consumption of contaminated meat products. Contamination with pathogenic bacteria is frequently found in the food production environment, and adequate household storage conditions of purchased foods are vital for illness avoidance. Real-time monitoring was used to evaluate bacterial growth in ground horse, beef, and pork meats maintained under various storage conditions. Various levels of E. coli O157:H7 carrying the luxCDABE operon, which allows the cells to emit bioluminescence, were used to inoculate meat samples that were then stored at room temperature for 0.5 day, at 4°C (cold) for 7 or 9 days, or −20°C (frozen) for 9 days. Real-time bioluminescence imaging (BLI) of bacterial growth was used to assess bacterial survival or load. Ground horse meat BLI signals and E. coli levels were dose and time dependent, increasing during room temperature and −20°C storage, but stayed at low levels during 4°C storage. No bacteria survived in the lower level inoculum groups (101 and 103 CFU/g). With an inoculum of 107 CFU/g, pork meats had higher BLI signals than did their beef counterparts, displaying decreased BLI signals during 7 days storage at 4°C. Both meat types had higher BLI signals in the fat area, which was confirmed with isolated fat tissues in the beef meat. Beef lean and fat tissues contrasted with both pork fat and lean tissues, which had significantly higher BLI signals and bacterial levels. BLI appears to be a useful research tool for real-time monitoring of bacterial growth and survival in various stored livestock meats. The dependence of E. coli O157:H7 growth on meat substrate (fat or lean) and storage conditions may be used as part of an effective antibacterial approach for the production of safe ground horse, beef, and pork meats.

Fate of Enterohemorrhagic Escherichia coli O157: H7 in Commercial Mayonnaise

1994 ◽  
Vol 57 (9) ◽  
pp. 780-783 ◽  
Author(s):  
TONG ZHAO ◽  
MICHAEL P. DOYLE
Keyword(s):  
Escherichia Coli ◽  
Enterohemorrhagic Escherichia Coli ◽  
Health Concern ◽  
Plate Count ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Initial Ph ◽  
Contaminated Food ◽  
Aerobic Plate Count ◽  
Mold And Yeast

The fate of enterohemorrhagic Escherichia coli O157:H7 was determined in three different lots of commercial mayonnaise, including four different samples from a lot implicated in an outbreak of E. coli O157:H7 infection. The initial pH of the products ranged from 3.6 to 3.9. Products were inoculated with 6.5 × 103 E. coli O157:H7/g and incubated at 5 or 20°C. Escherichia coli O157:H7 did not grow at either temperature but survived for 34 to 55 days at 5°C and for 8 to 21 days at 20°C, depending on the lot. Survival was greatest in real mayonnaise purchased at retail among six mayonnaise samples which included a reduced calorie mayonnaise. Escherichia coli O157:H7 populations decreased between 2- and 100-fold by 3 weeks at 5°C, and between 10- and 1,000-fold by 7 days at 20°C. There was little or no change in pH (<0.1 unit), aerobic plate count, mold and yeast count or Lactobacillus count (< 1 log10 CFU/g) for the duration of the study. Commercial mayonnaise manufactured under good manufacturing practices is not a public health concern. Abusive handling of mayonnaise resulting in cross-contamination with E. coli O157:H7-contaminated food or contamination by an infected foodhandler is the principal basis for concern.

Soil versus Pond Ash Surfacing of Feedlot Pens: Occurrence of Escherichia coli O157:H7 in Cattle and Persistence in Manure†

2010 ◽  
Vol 73 (7) ◽  
pp. 1269-1277 ◽  
Author(s):  
ELAINE D. BERRY ◽  
JAMES E. WELLS ◽  
TERRANCE M. ARTHUR ◽  
BRYAN L. WOODBURY ◽  
JOHN A. NIENABER ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Sampling Period ◽  
Escherichia Coli O157 ◽  
Surface Material ◽  
Beef Heifers ◽  
Pond Ash ◽  
E Coli ◽  
Cattle Feces ◽  
Naturally Occurring ◽  
Survival Differences

Reducing Escherichia coli O157:H7 in cattle and their manure is critical for reducing the risk for human foodborne and waterborne illness. The objective of this study was to evaluate the effects of soil and pond ash surfaces for feedlot pens on the prevalence, levels, and/or persistence of naturally occurring E. coli O157:H7 and total E. coli in cattle (feces and hides) and manure. Cattle (128 beef heifers) were sorted among 16 pens: 8 surfaced with soil and 8 surfaced with pond ash. The prevalence of E. coli O157:H7 in feces decreased (P < 0.0001) during the study from 57.0% on day 0 to 3.9% on day 84 but did not differ (P ≥ 0.05) between cattle on soil and on pond ash pens at any sampling period. The prevalence of the pathogen on hides and in feedlot surface material (FSM) also decreased (P < 0.0001), with no effect of soil or pond ash surface (P ≥ 0.05). Similarly, levels of E. coli in FSM did not differ (P ≥ 0.05) at any sampling period, and there were no clear trends for survival differences of E. coli O157:H7 or E. coli in FSM between pond ash and soil surfaces, although E. coli populations survived at 5.0 log CFU/g of FSM on the pen surfaces 6 weeks after the cattle were removed. These results indicate that housing cattle on pens surfaced with pond ash versus pens surfaced with soil does not affect E. coli O157:H7 in cattle or their manure.

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