Inactivation of Acid-Adapted and Nonadapted Escherichia coli O157:H7 during Drying and Storage of Beef Jerky Treated with Different Marinades

2002 ◽  
Vol 65 (9) ◽  
pp. 1394-1405 ◽  
Author(s):  
MEHMET CALICIOGLU ◽  
JOHN N. SOFOS ◽  
JOHN SAMELIS ◽  
PATRICIA A. KENDALL ◽  
GARY C. SMITH
Keyword(s):  
Escherichia Coli ◽  
Acetic Acid ◽  
Soy Sauce ◽  
Escherichia Coli O157 ◽  
Bacterial Populations ◽  
Acid Adaptation ◽  
E Coli ◽  
Significant Difference ◽  
Beef Jerky ◽  
And Storage

The inactivation of both acid-adapted and unadapted Escherichia coli O157:H7 during the processing of beef jerky was studied. Following inoculation with the pathogen, beef slices were subjected to different predrying marinade treatments, dried at 60°C for 10 h, and stored at 25°C for 60 d. The predrying treatments evaluated were as follows: (i) no treatment (C), (ii) traditional marinade (TM), (iii) double-strength TM modified with added 1.2% sodium lactate, 9% acetic acid, and 68% soy sauce with 5% ethanol (MM), (iv) dipping into 5% acetic acid for 10 min followed by application of TM (AATM), and (v) dipping into 1% Tween 20 for 15 min and then into 5% acetic acid for 10 min followed by TM (TWTM). Bacterial survivors were determined during drying and storage using tryptic soy agar with 0.1% pyruvate, modified eosin methylene blue agar, and sorbitol MacConkey agar. Results indicated that bacterial populations decreased during drying in the order of TWTM (4.9 to 6.7 log) > AATM > MM > C ≥ TM (2.8 to 4.9 log) predrying treatments. Populations of acid-adapted E. coli O157:H7 decreased faster (P < 0.05) in AATM and TWTM than nonadapted cells during drying, whereas no significant difference was found in inactivation of acid-adapted and nonadapted inocula in C and TM samples. MM was more effective in inactivating the nonadapted than the adapted inoculum. Bacterial populations continued to decline during storage and dropped below the detection limit (−0.4 log10 CFU/cm2) as early as day 0 (after drying) or as late as day 60, depending on acid adaptation, predrying treatment, and agar medium. The results indicated that acid adaptation may not increase resistance to the hurdles involved in jerky processing and that use of additional antimicrobial chemicals or preservatives in jerky marination may improve the effectiveness of drying in inactivating E. coli O157:H7.

Factors Influencing Attachment of Escherichia coli O157:H7 to Beef Tissues and Removal Using Selected Sanitizing Rinses‡

1996 ◽  
Vol 59 (5) ◽  
pp. 453-459 ◽  
Author(s):  
PINA M. FRATAMICO ◽  
FRANKIE J. SCHULTZ ◽  
ROBERT C. BENEDICT ◽  
ROBERT L. BUCHANAN ◽  
PETER H. COOKE
Keyword(s):  
Escherichia Coli ◽  
Acetic Acid ◽  
Surface Structures ◽  
Escherichia Coli O157 ◽  
Adipose Tissues ◽  
E Coli ◽  
Factors Influencing ◽  
Significant Difference ◽  
Phosphate Buffered Saline ◽  
Scanning Electron

Attachment of E. coli O157:H7 and E. coli K12 to beef tenderloin filet, chuck, and adipose tissues was studied. Most attachment occurred within 1 min of incubation; the number of attached organisms depended on the concentration of bacteria in the liquid inoculum. Similar levels of E. coli bound to the three types of beef tissues tested. E. coli O157:H7 was heavily piliated; however, there was no significant difference between levels of bound E. coli O157:H7 and E. coli K12, indicating that these surface structures apparently are not involved in attachment. Scanning electron photomicrographs of meat tissue and of purified collagen suggested that bacteria attached primarily to collagen fibers. Rinsing solutions consisting of 10% trisodium phosphate (TSP), 2% acetic acid (HAc), phosphate-buffered saline (PBS) and combinations of each were tested for effectiveness in reducing the number of attached E. coli. The level of bacteria removed from tenderloin tissue following TSP, HAc, or PBS rinses did not differ considerably. When beef tissues were stored at 4°C for 18 h after the various rinse combinations, TSP rinse treatments reduced the levels of E. coli K12 and O157:H7 attached to adipose tissue up to 3.4 and 2.7 log units, respectively, compared to PBS rinse treatments. Therefore, TSP may be effective for reducing populations of E. coli O157:H7 on beef carcass tissue.

Parameters Affecting the Efficacy of Spray Washes against Escherichia coli O157:H7 and Fecal Contamination on Beef†

1997 ◽  
Vol 60 (6) ◽  
pp. 614-618 ◽  
Author(s):  
CATHERINE N. CUTTER ◽  
WARREN J. DORSA ◽  
GREGORY R. SIRAGUSA
Keyword(s):  
Escherichia Coli ◽  
Acetic Acid ◽  
Tap Water ◽  
Physiological Saline ◽  
Tissue Type ◽  
Escherichia Coli O157 ◽  
Bacterial Populations ◽  
E Coli ◽  
Bovine Feces ◽  
Beef Carcass

A series of progressive experiments was conducted with a model carcass washer using tap water and 2% acetic acid sprays to determine if tissue type, inoculation menstruum, bacterial level, or spray temperature affect removal of bacteria from beef carcass tissue during spray washing. For the first experiment, prerigor (15 min postexsanguination), postrigor (24 h postexsanguination), or postrigor frozen (−20°C, 7 days), thawed, lean beef carcass tissue (BCT) was inoculated with bovine feces and subjected to spray washing (15 s, 56°C) with water or acetic acid. Spray washing with either compound resulted in bacterial populations that were similar for prerigor and postrigor BCT; however, remaining bacterial populations from spray-treated postrigor, frozen BCT were significantly (P ≤ 0.05) less than for the other two tissue types. For the second experiment, prerigor, lean BCT was inoculated with Escherichia coli O157:H7 suspended in bovine feces or physiological saline and spray washed (15 s, 56°C) with water or acetic acid. Bacterial populations were reduced to similar levels with acid sprays, regardless of menstruum. For the third experiment, E. coli O157:H7 in feces was used to contaminate prerigor lean BCT to obtain different initial bacterial levels (7, 5,3, and 1 log CFU/cm2). Spray washes (15 s, 56°C) with acetic acid reduced the level of the pathogen to 2.51 and 0.30 log CFU/cm2 when initial bacterial levels were 7 and 5 log CFU/cm2, and to undetectable levels when initial bacterial levels were 3 and 1 log CFU/cm2. In a fourth experiment, water or acetic acid (15 s), ranging from 30 to 70°C was applied to beef tissue contaminated with E. coli O157:H7 in feces. Remaining bacterial populations were not different between the water treatments or between the acid treatments at any temperature. While variables such as bacterial level and inoculation menstruum may affect the efficacy of spray washing with organic acids, these results indicate that tissue type or spray temperature do not.

Effects of Acid Adaptation and Modified Marinades on Survival of Postdrying Salmonella Contamination on Beef Jerky during Storage

2003 ◽  
Vol 66 (3) ◽  
pp. 396-402 ◽  
Author(s):  
MEHMET CALICIOGLU ◽  
JOHN N. SOFOS ◽  
PATRICIA A. KENDALL ◽  
GARY C. SMITH
Keyword(s):  
Acetic Acid ◽  
Sodium Lactate ◽  
Soy Sauce ◽  
Tween 20 ◽  
Bacterial Populations ◽  
Acid Adaptation ◽  
Direct Plating ◽  
Beef Jerky ◽  
Agar Media ◽  
Salmonella Survival

This study was undertaken to evaluate the survival of acid-adapted and nonadapted Salmonella cultures inoculated after drying on beef jerky that had been treated with marinades before drying at 60°C for 10 h. Beef slices were (i) not treated prior to refrigeration at 4°C for 24 h (control [C]); (ii) marinated with traditional marinade (TM), (iii) marinated with TM modified with 1.2% sodium lactate, 9% acetic acid, and 68% soy sauce containing 5% ethanol (MM) at twice the amount used in the TM treatment; (iv) dipped into 5% acetic acid and then marinated with TM (AATM); and (v) dipped into 1% Tween 20, then dipped into 5% acetic acid, and then marinated with TM (TWTM); after each treatment, meat slices were refrigerated at 4°C for 24 h prior to drying. Dried slices were inoculated with acid-adapted or nonadapted Salmonella (ca. 5.7 log CFU/cm2) prior to aerobic storage at 25°C for 60 days. Tryptic soy agar with 0.1% pyruvate, as well as xylose-lysine-tergitol 4 (XLT4) agar, was used to determine survivor counts. Bacterial decreases achieved with the different treatments were found to be in the following order: TWTM (5.4 to 6.3 log units) ≥ AATM ≥ MM > C ≥ TM (2.9 to 5.1 log units). Acid-adapted Salmonella decreased faster than nonadapted Salmonella for all treatments. Bacterial populations decreased to below the detection limit (−0.4 log CFU/cm2) in as few as 14 days or remained detectable by direct plating after 60 days of storage, depending on acid adaptation, treatment, and agar media. The results of this study indicate that the modified marinades used in jerky processing and the low water activity of the dried product provide antimicrobial effects against possible postprocessing contamination with Salmonella, while the preparation of cultures under acid-adaptation conditions did not increase Salmonella survival during storage and may have reduced it.

Influence of Acid Adaptation on the Tolerance of Escherichia coli O157:H7 to Some Subsequent Stresses

2002 ◽  
Vol 65 (2) ◽  
pp. 260-265 ◽  
Author(s):  
HSIN-YI CHENG ◽  
HSIN-YI YANG ◽  
CHENG-CHUN CHOU
Keyword(s):  
Escherichia Coli ◽  
Sodium Chloride ◽  
Bile Salt ◽  
Thermal Tolerance ◽  
The Other ◽  
Escherichia Coli O157 ◽  
Acid Adaptation ◽  
E Coli ◽  
Significant Difference ◽  
Test Organisms

Three stains of Escherichia coli O157:H7, including ATCC 43889, ATCC 43895, and 933, were first subjected to acid adaptation at a pH of 5.0 for 4 h. Thermal tolerance at 52°C and survival of the acid-adapted as well as the nonadapted cells of E. coli O157:H7 in the presence of 10% sodium chloride, 0.85% bile salt, or 15.0% ethanol were investigated. Results showed that the effect of acid adaptation on the survival of E. coli O157:H7 varied with the strains and types of subsequent stress. Acid adaptation caused an increase in the thermal tolerance of E. coli O157:H7 ATCC 43889 and ATCC 43895, but no significant difference in the thermal tolerance was noted between acid-adapted and nonadapted cells of E. coli O157:H7 933. Although the magnitude of increase varied with strains of test organisms, acid adaptation generally led to an increase in the tolerance of E. coli O157:H7 to sodium chloride. On the other hand, the susceptibility of acid-adapted cells of the three strains of E. coli O157:H7 tested did not show a significant difference from that of their nonadapted counterparts when stressed with bile salt. The acid-adapted cells of E. coli O157:H7 ATCC 43889 and ATCC 43895 were less tolerant than the nonadapted cells to ethanol, whereas the tolerance of adapted and nonadapted cells of E. coli O157:H7 933 showed no significant differences.

Viability of Acid-Adapted Escherichia coli O157:H7 in Ground Beef Treated with Acidic Calcium Sulfate

2004 ◽  
Vol 67 (3) ◽  
pp. 591-595 ◽  
Author(s):  
LARRY R. BEUCHAT ◽  
ALAN J. SCOUTEN
Keyword(s):  
Escherichia Coli ◽  
Acetic Acid ◽  
Calcium Sulfate ◽  
Ground Beef ◽  
Storage Period ◽  
Acid Tolerance ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Acidic Environments ◽  
Subsequent Acid

The effects of lactic acid, acetic acid, and acidic calcium sulfate (ACS) on viability and subsequent acid tolerance of three strains of Escherichia coli O157:H7 were determined. Differences in tolerance to acidic environments were observed among strains, but the level of tolerance was not affected by the acidulant to which cells had been exposed. Cells of E. coli O157:H7 adapted to grow on tryptic soy agar acidified to pH 4.5 with ACS were compared to cells grown at pH 7.2 in the absence of ACS for their ability to survive after inoculation into ground beef treated with ACS, as well as untreated beef. The number of ACS-adapted cells recovered from ACS-treated beef was significantly (α = 0.05) higher than the number of control cells recovered from ACS-treated beef during the first 3 days of a 10-day storage period at 4°C, suggesting that ACS-adapted cells might be initially more tolerant than unadapted cells to reduced pH in ACS-treated beef. Regardless of treatment of ground beef with ACS or adaptation of E. coli O157:H7 to ACS before inoculating ground beef, the pathogen survived in high numbers.

Simultaneous Enrichment of Shiga Toxin–Producing Escherichia coli O157 and O26 and Salmonella in Food Samples Using Universal Preenrichment Broth

2009 ◽  
Vol 72 (10) ◽  
pp. 2065-2070 ◽  
Author(s):  
MASASHI KANKI ◽  
KAZUKO SETO ◽  
JUNKO SAKATA ◽  
TETSUYA HARADA ◽  
YUKO KUMEDA
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Food Samples ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Significant Difference ◽  
Peptone Water ◽  
Radish Sprouts ◽  
Pork Samples ◽  
Better Than

Universal preenrichment broth (UPB) was compared with modified Escherichia coli broth with novobiocin (mEC+n) for enrichment of Shiga toxin–producing E. coli O157 and O26, and with buffered peptone water (BPW) for preenrichment of Salmonella enterica. Ten strains each of the three pathogens were inoculated into beef and radish sprouts following thermal, freezing, or no treatment. With regard to O157 and O26, UPB incubated at 42°C recovered significantly more cells from inoculated beef than UPB at 35°C and from radish sprout samples than UPB at 35°C and mEC+n. With regard to Salmonella, UPB incubated at 42°C was as effective as UPB at 35°C and BPW at recovering cells from beef and radish sprout samples. No significant difference was noted between the effectiveness of UPB at 42°C and UPB at 35°C or BPW in the recovery of Salmonella from 205 naturally contaminated poultry samples. By using UPB at 42°C, one O157:H7 strain was isolated from the mixed offal of 53 beef samples, 6 cattle offal samples, and 50 pork samples all contaminated naturally, with no pathogen inoculation. The present study found that UPB incubated at 42°C was as effective as, or better than, mEC+n for enrichment of O157 and O26 and comparable to BPW for preenrichment of Salmonella. These findings suggest that a great deal of labor, time, samples, and space may be saved if O157, O26, and Salmonella are enriched simultaneously with UPB at 42°C.

Efficacy of Selected Acidulants in Pureed Green Beans Inoculated with Pathogens (Escherichia coli O157:H7 and Listeria monocytogenes)

2006 ◽  
Vol 69 (8) ◽  
pp. 1865-1869 ◽  
Author(s):  
AAKASH KHURANA ◽  
GEORGE B. AWUAH ◽  
BRADLEY TAYLOR ◽  
ELENA ENACHE
Keyword(s):  
Escherichia Coli ◽  
Acetic Acid ◽  
Listeria Monocytogenes ◽  
Titratable Acidity ◽  
Combined Effect ◽  
Escherichia Coli O157 ◽  
Green Beans ◽  
E Coli ◽  
Acid Ph ◽  
D Values

Studies were conducted to evaluate the combined effect of selected acidulants (acetic, citric, malic, and phosphoric acid) and heat on foodborne pathogens (Escherichia coli O157:H7 and Listeria monocytogenes) in pureed green beans. To establish a consistent reference point for comparison, the molar concentrations of the acids remained constant while the acid-to-puree ratio, titratable acidity, and undissociated acid were either measured or calculated for a target acidified green beans at a pH of 3.8, 4.2, and 4.6. The D-values at 149°F were used as the criteria for acid efficacy. Generally, acetic acid (puree, pH 3.8 and 4.2) represented the most effective acid with comparatively low D-values irrespective of the target microorganism. A 10-s heating at 149°F inactivated approximately 106 CFU/ml of E. coli O157:H7 in pureed beans at pH 3.8. The efficacy of acetic acid is likely related to the elevated percent titratable acidity, undissociated acid, and acid-to-puree ratio. The effectiveness (which in this study represents the combined effect of acid and heat) of the remaining acids (citric, malic, and phosphoric) at puree pH values of 3.8 and 4.2 were statistically insignificant (α = 0.05). Surprisingly, acetic acid (puree, pH 4.6) appeared to be the least effective as compared to the other acids tested (citric, malic, and phosphoric) especially on E. coli O157:H7 cells, while L. monocytogenes had a similar resistance to all acids at puree pH 4.6. With the exception of citric acid (pH 3.8), acetic acid (pH 4.6), and malic acid (pH 3.8 and 4.6), which were statistically insignificant (P > 0.05), the D-values for L. monocytogenes were statistically different (P ≤ 0.05) and higher than the D-values for E. coli under similar experimental conditions. A conservative process recommendation (referred to as the “safe harbor” process) was found sufficient and applicable to pureed green beans for the pH range studied.

Fate of Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella typhimurium during Preparation and Storage of Beef Jerky

1996 ◽  
Vol 59 (12) ◽  
pp. 1336-1338 ◽  
Author(s):  
JUDY A. HARRISON ◽  
MARK A. HARRISON
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Salmonella Typhimurium ◽  
Microbial Populations ◽  
Escherichia Coli O157 ◽  
Beef Jerky ◽  
Drying Up ◽  
Moisture Conditions ◽  
And Storage

The fate of Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella typhimurium during preparation and storage of beef jerky was determined. Control strips and one-half of the inoculated beef loin strips were marinated at 4°C overnight and dried at 60°C (140°F) for 10h. The remaining half of the inoculated samples were heated in marinade to 71.1°C (160°F). Strips were dried at 60°C (140°F) for 10 h. Microbial populations were determined at intervals during drying up to 10 h and also from samples stored at 25°C for 8 weeks at various moisture levels. In general, L. monocytogenes was more resistant to the treatments. After 3 h of drying, populations on the unheated, inoculated samples were reduced by 3.3, 1.8 and 3.1 log units, respectively, and all three were reduced by 5.5 to 6.0 log units after 10h. Reduction of the three populations on strips that were cooked prior to drying was 4.5 to 5.5 log units immediately after cooking. The populations decreased to undetectable levels after 10 h of drying. None of the three pathogens were detected on the controls. After 8 weeks of storage none of the pathogens were detected, indicating that they were unable to recover under the moisture conditions during storage.

scholarly journals Effects of Acid Adaptation, Product pH, and Heating on Survival of Escherichia coli O157:H7 in Pepperoni

2000 ◽  
Vol 66 (4) ◽  
pp. 1726-1729 ◽  
Author(s):  
Denise C. R. Riordan ◽  
Geraldine Duffy ◽  
James J. Sheridan ◽  
Richard C. Whiting ◽  
Ian S. Blair ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Thermal Inactivation ◽  
Escherichia Coli O157 ◽  
Acid Adaptation ◽  
E Coli

ABSTRACT The thermotolerance of E. coli O157:H7 cells (strain 380-94) heated in pepperoni is reported. Information on the pattern of thermal inactivation of E. coli O157:H7 in pepperoni was applied in the development of heating processes designed to reduceE. coli O157:H7 numbers therein by 5 log10units.

Ascorbic Acid Enhances Destruction of Escherichia coli O157:H7 during Home-Type Drying of Apple Slices

2001 ◽  
Vol 64 (8) ◽  
pp. 1244-1248 ◽  
Author(s):  
JENNIFER A. BURNHAM ◽  
PATRICIA A. KENDALL ◽  
JOHN N. SOFOS
Keyword(s):  
Escherichia Coli ◽  
Ascorbic Acid ◽  
Acid Solution ◽  
Escherichia Coli O157 ◽  
Bacterial Populations ◽  
Ascorbic Acid Solution ◽  
Initial Inoculum ◽  
E Coli ◽  
Apple Slices ◽  
Agar Media

Destruction of Escherichia coli O157:H7 was evaluated on inoculated apple slices dehydrated at two temperatures with and without application of predrying treatments. Half-ring slices (0.6 cm thick) of peeled and cored Gala apples were inoculated by immersion for 30 min in a four-strain composite inoculum of E. coli O157:H7. The inoculated slices (8.7 to 9.4 log CFU/g) either received no predrying treatment (control), were soaked for 15 min in a 3.4% ascorbic acid solution, or were steam blanched for 3 min at 88°C immediately prior to drying at 57.2 or 62.8°C for up to 6 h. Samples were plated on tryptic soy (TSA) and sorbitol MacConkey (SMAC) agar media for direct enumeration of surviving bacterial populations. Steam blanching changed initial inoculation levels by +0.3 to −0.7 log CFU/g, while immersion in the ascorbic acid solution reduced the inoculation levels by 1.4 to 1.6 log CFU/g. Dehydration of control samples for 6 h reduced mean bacterial populations by 2.9 log CFU/g (TSA or SMAC) at 57.2°C and by 3.3 (SMAC) and 3.5 (TSA) log CFU/g at 62.8°C. Mean decreases from initial inoculum levels for steam-blanched slices after 6 h of drying were 2.1 (SMAC) and 2.0 (TSA) log CFU/g at 57.2°C, and 3.6 (TSA or SMAC) log CFU/g at 62.8°C. In contrast, initial bacterial populations on ascorbic acid–pretreated apple slices declined by 5.0 (SMAC) and 5.1 (TSA) log CFU/g after 3 h of dehydration at 57.2°C, and by 7.3 (SMAC) and 6.9 (TSA) log CFU/g after 3 h at 62.8°C. Reductions on slices treated with ascorbic acid were in the range of 8.0 to 8.3 log CFU/g after 6 h of drying, irrespective of drying temperature or agar medium used. The results of immersing apple slices in a 3.4% ascorbic acid solution for 15 min prior to drying indicate that a predrying treatment enhances the destruction of E. coli O157:H7 on home-dried apple products.

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