Antimicrobial Intervention and Process Validation in Beef Jerky Processing 

M. A. Harrison, R. K. Singh, J. A. Harrison, and N. Singh, University of Georgia 

Final Report 

Final Report – Summary 

January 20, 2006 

Antimicrobial Intervention and Process Validation in Beef Jerky Processing 

Mark A. Harrison, Rakesh K. Singh, Judy A. Harrison, and Nepal Singh 

University of Georgia 

Beef jerky is classified by the USDA as a heat-treated, shelf stable ready to eat meat product. 

Small and very small commercial processors of meat jerky products are currently under pressure 

to show their processes are sufficient to provide a finished product that is safe. Foodborne 

pathogens related to jerky of concern to the industry and regulators include Salmonella, 

Escherichia coli O157:H7, and Listeria monocytogenes. Marination, which is an optional step, 

can involve the use of ingredients that can affect the survival of foodborne pathogens on jerky 

products. Jerky processors may use a variety of marinade ingredients and methods for 

application. In addition, processors may opt to use chemical antimicrobial treatments prior to the 

drying process. Many small processors use dehydrators, rather than smokehouses to process 

their product. The issue of humidity control during drying and its effect of pathogen survival has 

been raised. Humidity in a dehydrator is more difficult to control compared to a smokehouse. 

This project evaluated several variations in the production of beef jerky to produce quality 

products that can satisfy needs of small and very small meat processors for development of their 

HACCP plans to address concerns with Salmonella spp, E. coli O157:H7, and L. monocytogenes. 

Challenge studies using all three pathogens were done. We evaluated the use of a marination 

step, chemical pretreatment, and drying procedures using either a dehydrator or smokehouse. 

The chemical pretreatments involved using chlorine dioxide (500 and 1200 ppm) and acidic 

calcium sulfate (1:2 and 1:3 water: calcium sulfate ratios). Attempts were also made to use 

ozone as a pretreatment. The temperature conditions in the dehydrator and smokehouse were 

similar to allow for comparison. The relative humidity in the smokehouse was maintained at 

33%. 

Beef jerky strips were made using a horizontal-flow dehydrator set at 62oC (143.6oF) and a 

commercial-type smokehouse with a dry-bulb/wet-bulb setting of 63o

C/43oC (145oF/110oF) 

(33% relative humidity) in combination with calcium sulfate and chlorine dioxide pretreatments 

to determine the effectiveness of the treatments in the inactivation of Salmonella, E. coli 

O157:H7, and L. monocytogenes for whole strip beef jerky. Calcium sulfate and chlorine 

dioxide were used in concentrations recommended by the manufacturers. Inoculated strips were 

marinated overnight in a marinade containing water (3.0 liters), salt (171.00 g), sugar (57.00 g), 

nitrite (3.56 g), garlic powder (5.68 g), sodium erythorbate (14.20 g), MSG (7.90 g), vinegar 

(4%, 171.00 g), Worchestershire sauce (14.20 g), and thyme (7.10 g) before drying. Trials were 

conducted separately with three replications on three different days for each experiment. 

Enumeration of the pathogens used in the study was done using selective plating media. The 

data were compared statistically to determine if each combination of pretreatment and drying 

method could reduce the populations of E. coli O157:H7 and L. monocytogenes by at least 5 logs 

1 
Antimicrobial Intervention and Process Validation in Beef Jerky Processing 

M. A. Harrison, R. K. Singh, J. A. Harrison, and N. Singh, University of Georgia 

Final Report 

and Salmonella populations by at least 6.5 logs. The effectiveness of the different pretreatments 

was also compared. 

Statistical analysis showed the populations of E. coli O157:H7 were reduced by at least 5 logs 

cfu/strip for all of the treatments except for jerky pretreated with the lower concentration of 

chlorine dioxide and dried in the dehydrator. For L. monocytogenes, 5 log reductions were noted 

for all the treatments regardless of the drying method. Salmonella populations were reduced by 

more than 6.5 logs on jerky strips that were pretreated with the higher concentration of calcium 

sulfate and dried in the dehydrator and jerky pretreated with the 1200 ppm concentration of 

chlorine dioxide and dried in the smokehouse. Populations were reduced almost as well on jerky 

pretreated with calcium sulfate, both concentrations, and dried in the smokehouse. 

There was no statistical difference in the effectiveness of the pretreatments in contributing to the 

reduction of E. coli and L. monocytogenes populations, although it is possible to rank them with 

the higher concentration of calcium sulfate being more effective and the lower concentration of 

chlorine dioxide being least effective. For Salmonella, both concentrations of the calcium sulfate 

were the most effective in reducing the populations while the lower concentration of chlorine 

dioxide was least effective. 

Pretreatments with ozone were unsuccessful due to difficulties in generating sufficient levels of 

ozone in pretreatment waters that were to be used. After repeated attempts to correct the 

situation, desired levels could not be attained. 

While effective treatments may be attained using a dehydrator coupled with an antimicrobial 

pretreatment, processing jerky in the smokehouse with similar temperature conditions was more 

effective. In general, the acidic calcium sulfate was a more effective pretreatment than chlorine 

dioxide. Small processors using dehydrators with little control over maintaining consistent 

relative humidity conditions within the drying chamber may find the use of these antimicrobial 

treatments beneficial in achieving the desired level of pathogen reduction. 

2 
Antimicrobial Intervention and Process Validation in Beef Jerky Processing 

M. A. Harrison, R. K. Singh, J. A. Harrison, and N. Singh, University of Georgia 

Final Report 

Final Report – Full Report 

January 20, 2006 

Antimicrobial Intervention and Process Validation in Beef Jerky Processing 

Mark A. Harrison, Rakesh K. Singh, Judy A. Harrison, and Nepal Singh

 University of Georgia 

Beef jerky is classified by the USDA as a heat-treated, shelf stable ready to eat meat product. 

Small and very small commercial processors of meat jerky products are currently under pressure 

to show their processes are sufficient to provide a finished product that is safe. Foodborne 

pathogens related to jerky of concern to the industry and regulators include Salmonella, 

Escherichia coli O157:H7, and Listeria monocytogenes. Marination, which is an optional step, 

can involve the use of ingredients that can affect the survival of foodborne pathogens on jerky 

products. Jerky processors may use a variety of marinade ingredients and methods for 

application. In addition, processors may opt to use chemical antimicrobial treatments prior to the 

drying process. Many small processors use dehydrators, rather than smokehouses to process 

their product. The issue of humidity control during drying and its effect of pathogen survival has 

been raised. Humidity in a dehydrator is more difficult to control compared to a smokehouse. 

This project evaluated several variations in the production of beef jerky to produce quality 

products that can satisfy needs of small and very small meat processors for development of their 

HACCP plans to address concerns with Salmonella spp., E. coli O157:H7, and L. 

monocytogenes. Challenge studies using all three pathogens were done. We evaluated the use of 

a marination step, chemical pretreatment, and drying procedures using either a dehydrator or 

smokehouse. The chemical pretreatments involved using chlorine dioxide (500 and 1200 ppm) 

and acidic calcium sulfate (1:2 and 1:3 water: calcium sulfate ratios). Attempts were also made 

to use ozone as a pretreatment. The temperature conditions in the dehydrator and smokehouse 

were similar to allow for comparison. The relative humidity in the smokehouse was maintained 

at 33%. 

Approach: 

Beef jerky strips were made using a horizontal dehydrator and a commercial-type smokehouse in 

combination with calcium sulfate and chlorine dioxide pretreatments to determine the 

effectiveness of the treatment in the inactivation of Salmonella, E. coli O157:H7, and L. 

monocytogenes for whole strip beef jerky. Inoculated strips were marinated overnight in a 

marinade containing water (3 liters), salt (171.00 g), sugar (57.00 g), nitrite (3.56 g), garlic 

powder (5.68 g), sodium erythorbate (14.20 g), MSG (7.90 g), vinegar (4%, 171.00 g), 

Worchestershire sauce (14.20 g), and thyme (7.10 g) before drying. Trials were conducted 

separately with three replications on three different days for each experiment. In addition, we 

tried to use ozone as a pretreatment. 

Jerky Processing Using a Dehydrator: 

Microbial inactivation data for beef jerky strips that were either treated or not treated with 

calcium sulfate (Mionix Safe2OTM, Mionix Corporation, Rocklin, CA) before marinating and 

3 
Antimicrobial Intervention and Process Validation in Beef Jerky Processing 

M. A. Harrison, R. K. Singh, J. A. Harrison, and N. Singh, University of Georgia 

Final Report 

drying in a horizontal-flow dehydrator 62o

C (143.6oF) are in Tables 1 and 2. Table 1 contains 

bacterial enumeration data at various stages of processing using plate count agar (PCA) as the 

plating medium. This medium will allow the inoculated pathogens on the product to grow, as 

well as, the naturally occurring bacteria present on the strips. More detailed descriptions of the 

effects the treatments have on pathogen survival are described below focusing on pathogen 

enumeration on selective plating media. 

The manufacturer’s recommended levels of 1:2 and 1:3 mixtures of Mionix Safe2OTM with water 

were used as a 30 sec product dip. Treatment of the inoculated strips prior to drying with the 1:2 

mix and the 1:3 mix reduced the E. coli O157:H7 populations as determined using selective 

plating medium by 0.97 to 1.23 logs, with the higher concentration yielding the greatest 

reduction. In comparison, the water control treatment reduced the populations by only 0.1 log 

cfu/strip (Table 2). Marination reduced the populations slightly, with a greater reduction 

occurring on the water control. After drying, the E. coli O157:H7 populations were reduced to 

levels below the detection limit for the plating method (>6.68 log reduction). However, when 

samples were enriched there was still some viable E. coli O157:H7 present on the strips after 

processing. Stored product was sampled over a 3 month period. After 1 month, no E. coli 

O157:H7 was detected on strips that were pretreated with the calcium sulfate treatments. Only 

the water treated samples yielded positive samples. Thus the calcium sulfate pretreatment was 

more effective in eliminating the pathogen than water alone. No E. coli O157:H7 was detected 

by enumeration or after enrichment from any of the samples after 2 and 3 months. There was no 

noticeable changes in the product’s aw or pH during storage. The relative humidity in the 

dehydrators for the calcium sulfate experiments at the start of the drying process was 72.5%. 

For strips that were inoculated with L. monocytogenes before either treating or not treating with 

calcium sulfate and dehydration, population reductions and patterns were similar to that seen 

with E. coli O157:H7 (Table 2). L. monocytogenes appears to be slightly more resistant to the 

chemical pretreatment and the drying than E. coli O157:H7. However, the population of L. 

monocytogenes on these strips was reduced by >6 logs. Use of the greater concentration of the 

calcium sulfate reduced the populations to a greater degree than did the lower concentration. 

When sampled before product storage, enrichment of the samples recovered viable L. 

monocytogenes from most of the samples even if the enumeration of the pathogen was not 

possible. When sampled at monthly intervals during storage, no L. monocytogenes positive 

samples were detected by enumeration or enrichment regardless of the pretreatment. As with the 

E. coli O157:H7 samples, there was no noticeable change in the product aw or pH. The relative 

humidity in the dehydrators for the calcium sulfate experiments at the start of the drying process 

was 61.1%. 

Salmonella appears to be more resistant to the chemical pretreatment and the drying process than 

the other two pathogens (Table 2). While the greater concentration of calcium sulfate reduced 

the populations of Salmonella by at least 7.18 logs, there was a reduction of 6.78 and 4.91 for the 

1:3 calcium sulfate mix and the water control, respectively. As was the case prior to drying with 

the other two pathogens, pretreatment with the 1:2 calcium sulfate mix was more effective in 

reducing the pathogen populations compared to the 1:3 mix. During storage, positive Salmonella 

samples were detected from all or some of the replications that received the water pretreatment. 

One replication that was treated with the 1:3 calcium sulfate pretreatment after 1 month was 

4 
Antimicrobial Intervention and Process Validation in Beef Jerky Processing 

M. A. Harrison, R. K. Singh, J. A. Harrison, and N. Singh, University of Georgia 

Final Report 

positive for Salmonella, but no samples receiving this treatment were positive after 2 or 3 

months. All samples treated with the 1:2 mix were negative for Salmonella at all monthly 

sampling times. The aw or pH of the product was not changed during storage. The relative 

humidity in the dehydrators for the calcium sulfate experiments at the start of the drying process 

was 55.4%. 

Microbial inactivation data for beef jerky strips that were either treated or not treated with 

chlorine dioxide (Keeper®, Bio-Cide International, Inc., Norman, OK) before marinating and 

drying in the dehydrator are in Tables 3 and 4. Table 3 contains bacterial enumeration data at 

various stages of processing using plate count agar (PCA) as the plating medium. More detailed 

descriptions of the effects the treatments have on pathogen survival are described below focusing 

on pathogen enumeration on selective plating media. 

Trials using chlorine dioxide and the dehydrator were completed with all 3 pathogens (Table 4). 

A 5 log reduction of E. coli O157:H7 was achieved with the chlorine dioxide pretreatments and 

the water control in this experiment, but the reduction was greatest on strips exposed to the 

higher calcium sulfate concentration. Since populations on the control strips for the chlorine 

dioxide treatments were not reduced to the same degree as those on the controls in the calcium 

sulfate experiments (>6.68 compared to 6.11), it is possible that there is some additive or 

synergistic effect from the calcium sulfate that was not present with the chlorine dioxide. After 1 

month, no E. coli O157:H7 was recovered by enumeration methods, but enrichment of the 

samples pretreated with both concentrations of chlorine dioxide did recover the pathogen from 

samples for most of the replications. Enrichment of the water pretreated samples was negative 

for E. coli O157:H7. The relative humidity in the dehydrators for the chlorine dioxide 

experiments at the start of the drying process was 80.3%. This was approximately 8% higher 

than that for the dehydrators for the calcium sulfate experiments. 

There was little difference in the effectiveness of the two chlorine dioxide pretreatments. In fact 

the magnitude of population reduction was less than a log different than the control water 

treatment. After drying, the log reduction in the L. monocytogenes populations for the chlorine 

dioxide pretreated samples and the control was 6.55 or higher. A reduction of 4.18 was noted on 

the control strips. After 1 month storage, the populations were not detected by enumeration (at 

least a 6.68 log reduction) or by enrichment. The relative humidity in the dehydrator at the start 

of the drying process was 59.3%. 

Salmonella populations decreased by 5.34, 4.94, and 4.75 logs cfu/strip on strips treated with 

1,200 ppm chlorine dioxide, 500 ppm chlorine dioxide, and water (control), respectively. The 

pretreatment alone decreased the population by 0.6 log cfu/strip or less regardless of the 

concentration. There was a further decrease in the population for a total reduction of at least 

6.68 logs during the first month of product storage. Except for 1 of the control water pretreated 

samples, Salmonella was not recovered from any of the samples by enrichment after 1 month of 

product storage. The relative humidity in the dehydrator was 57.0%. 

Jerky Processing Using a Smokehouse: 

To establish a possible worst-case situation, we used wet-bulb/dry-bulb temperatures that would 

not typically be recommended. The dry-bulb temperature was 63o

C (145oF) and the wet-bulb 

5 
Antimicrobial Intervention and Process Validation in Beef Jerky Processing 

M. A. Harrison, R. K. Singh, J. A. Harrison, and N. Singh, University of Georgia 

Final Report 

temperature was 43.3o

C (110oF). The relative humidity was 33%. In using the low relative 

humidity and temperature conditions, we were trying to minimize the effect of chamber relative 

humidity and to allow us to compare a questionable smokehouse practice to the dehydrator 

conditions we evaluated. 

Tables 5-8 contain enumeration data for total aerobic bacteria and for Salmonella, E. coli 

O157:H7, and L. monocytogenes. In all cases, the populations were decreased by more than 6 

logs cfu/strip. Even though the relative humidity was low in the smokehouse, the minimal 

temperature condition used was effective in reducing the bacterial populations. 

Water Activity and pH: 

Tables 9-12 contain the water activity and pH values for the products that were processed in the 

dehydrator and the smokehouse. 

Ozone Pretreatments: 

We experienced difficulty in getting enough ozone captured in the pretreatment waters. We 

modified our ozone generator to correct the problem but could not obtain suitable levels. Thus, 

we could not evaluate this pretreatment. 

Summary 

Enumeration of the pathogens used in the study was done using selective plating media. The 

data were compared statistically to determine if each combination of pretreatment and drying 

method could reduce the populations of E. coli O157:H7 and L. monocytogenes by at least 5 logs 

and Salmonella populations by at least 6.5 logs. The effectiveness of the different pretreatments 

was also compared. 

Statistical analysis showed the populations of E. coli O157:H7 were reduced by at least 5 logs 

cfu/strip for all of the treatments except for jerky pretreated with the lower concentration of 

chlorine dioxide and dried in the dehydrator. For L. monocytogenes, 5 log reductions were noted 

for all the treatments regardless of the drying method. Salmonella populations were 

significantly reduced (p<0.05) by more than 6.5 logs on jerky strips that were pretreated with the 

higher concentration of calcium sulfate and dried in the dehydrator and jerky pretreated with the 

1200 ppm concentration of chlorine dioxide and dried in the smokehouse. Similar results were 

obtained for jerky pretreated with either concentration of calcium sulfate and dried in the 

smokehouse (p=0.055). 

There was no statistical difference in the effectiveness of the pretreatments in contributing to the 

reduction of E. coli and L. monocytogenes populations, although it is possible to rank them with 

the higher concentration of calcium sulfate being more effective and the lower concentration of 

chlorine dioxide being the least. For Salmonella, both concentrations of the calcium sulfate were 

the most effective in reducing the populations while the lower concentration of chlorine dioxide 

was least effective. 

6 
Antimicrobial Intervention and Process Validation in Beef Jerky Processing 

M. A. Harrison, R. K. Singh, J. A. Harrison, and N. Singh, University of Georgia 

Final Report 

Additional Comments: 

Most jerky processors who have contacted us over the years use dehydrators rather than 

smokehouses to process their product. Ingram, et al. (Interim Report, Wisconsin Study) showed 

the percent relative humidity (%RH) control in smokehouses during jerky processing is 

important. No such data using dehydrators is available. Humidity control in dehydrators 

presents challenges that cannot be addressed using a smokehouse. For instance, the %RH in 

dehydrators is influenced by the %RH of the room air, which can widely vary. This is especially 

true for the initial operating period during the drying process. 

7 
c 

Antimicrobial Intervention and Process Validation in Beef Jerky Processing M. A. Harrison, R. K. Singh, J. A. Harrison, and N. Singh, University of Georgia Final Report Table 1. Survival of Salmonella, E. coli O157:H7, and L. monocytogenes (log cfu/strip) on marinated, whole stri

pretreated with Mionix Safe2OTM (calcium sulfate) or not pretreated and dried in a horizontal dehydrator 

Enumeration was on plate count agar (PCA). 

 1:2a 1:3b 

Inoculated After After After Inoculated After After After Inoculated A

pretreated pretreated marinatedd dryinge pretreated pretreated marinatedd dryinge pretreated pret

Salmonella 8.79 6.81 6.23 <1.6f 8.79 7.18 6.93 2.89 8.79 8

E. coli O157:H7 8.39 7.33 7.24 <1.6 8.39 7.62 7.41 <1.6 8.39 8

L. monocytogenes 8.54 8.04 7.57 <1.6 8.54 8.25 7.93 <1.6 8.54 8

a 1 part Mionix concentrate with 2 parts water, dipped for 30 secb 1 part Mionix concentrate with 3 parts water, dipped for 30 sec 

Dipped in tap water for 30 sec

d Marinade composed of: water, salt, sugar, vinegar, Worcestershire sauce, sodium erythrobate, MSG, thym

sodium nitrite 

e Drying time approx 8-9 h; no humidity control f Enumeration below detection level; positive identification of organisms after enrichment 
c 

Antimicrobial Intervention and Process Validation in Beef Jerky Processing M. A. Harrison, R. K. Singh, J. A. Harrison, and N. Singh, University of Georgia Final Report Table 2. Survival of Salmonella, E. coli O157:H7, and L. monocytogenes (log cfu/strip) on marinated, w

pretreated with Mionix Safe2OTM (calcium sulfate) or not pretreated and dried in a horizontal dehydra

Enumeration of Salmonella, E. coli O157:H7, and L. monocytogenes was on bismuth sulfite MacConkey agar (SMAC) and Listeria selective agar (LSA), respectively.

 1:2a 1:3b 

Inoculated After After After Inoculated After After After Inoculated A

pretreated pretreated marinatedd dryinge pretreated pretreated marinatedd dryinge pretreated pret

Salmonella 8.78 6.56 6.15 1.6 8.78 7.09 6.85 2.06 8.78 8E. coli O157:H7 8.28 7.05 7.02 <1.6f 8.28 7.31 7.22 <1.6 8.28 8

L. monocytogenes 8.48 7.66 7.27 <1.6 8.48 7.85 7.74 <1.6 8.48 8

a 1 part Mionix concentrate with 2 parts water, dipped for 30 secb 1 part Mionix concentrate with 3 parts water, dipped for 30 sec 

Dipped in tap water for 30 sec

d Marinade composed of: water, salt, sugar, vinegar, Worcestershire sauce, sodium erythrobate, MSG, thym

sodium nitrite 

e Drying time approx 8-9 h; no humidity control f Enumeration below detection level; positive identification of organisms after enrichment 
c 

Antimicrobial Intervention and Process Validation in Beef Jerky Processing M. A. Harrison, R. K. Singh, J. A. Harrison, and N. Singh, University of Georgia Final Report Table 3. Survival of Salmonella, E. coli O157:H7, and L. monocytogenes (log cfu/strip) on marinated, whole stri

pretreated with Keeper® (chlorine dioxide) or not pretreated and dried in horizontal dehydrator at 62°C 

Enumeration was on plate count agar (PCA). 

 Pretreatment Aa Pretreatment Bb 

Inoculated After After After Inoculated After After After Inoculated A

pretreated pretreated marinatedd dryinge pretreated pretreated marinatedd dryinge pretreated pret

Salmonella 8.28 7.77 7.35 3.46 8.28 8.14 7.35 3.61 8.28 8E. coli O157:H7 8.57 7.97 7.24 3.38 8.57 8.43 7.55 3.44 8.57 8L. monocytogenes 8.28 8.17 7.56 3.59 8.28 8.25 7.79 3.44 8.28 8

a Pretreatment A: 1,200 ppm ClO2 

b Pretreatment B: 500 ppm ClO2 

Dipped in tap water for 30 sec

d Marinade composed of: water, salt, sugar, vinegar, Worcestershire sauce, sodium erythorbatethrobate, MS

powder, sodium nitrite 

e Drying time approx 8-9 h; no humidity control 
c 

Antimicrobial Intervention and Process Validation in Beef Jerky Processing M. A. Harrison, R. K. Singh, J. A. Harrison, and N. Singh, University of Georgia Final Report Table 4. Survival of Salmonella, E. coli O157:H7, and L. monocytogenes (log cfu/strip) on marinated, whole stri

pretreated with Keeper® (chlorine dioxide) or not pretreated and dried in horizontal dehydrator at 62°C 

Enumeration of Salmonella, E. coli O157:H7, and L. monocytogenes was on bismuth sulfite agar (BSA

MacConkey agar (SMAC) and Listeria selective agar (LSA), respectively.

 Pretreatment Aa Pretreatment Bb 

Inoculated After After After Inoculated After After After Inoculated A

pretreated pretreated marinatedd dryinge pretreated pretreated marinatedd dryinge pretreated pret

Salmonella 8.29 7.68 7.28 2.95 8.29 8.17 7.33 3.35 8.29 8E. coli O157:H7 8.49 7.86 7.17 2.08 8.49 8.36 7.38 3.41 8.49 8L. monocytogenes 8.15 8.03 7.40 <1.6f 8.15 8.11 7.57 1.60 8.15 8

a Pretreatment A: 1,200 ppm ClO2 

b Pretreatment B: 500 ppm ClO2 

Dipped in tap water for 30 sec

d Marinade composed of: water, salt, sugar, vinegar, Worcestershire sauce, sodium erythorbatethrobate, MS

powder, sodium nitrite 

e Drying time approx 8-9 h; no humidity control f Enumeration below detection level; positive identification of organisms after enrichment 
c 

Antimicrobial Intervention and Process Validation in Beef Jerky Processing M. A. Harrison, R. K. Singh, J. A. Harrison, and N. Singh, University of Georgia Final Report Table 5. Survival of Salmonella, E. coli O157:H7, and L. monocytogenes (log cfu/strip) on marinated, whole stri

pretreated with Mionix Safe2OTM (calcium sulfate) or not pretreated and dried in a smokehouse at 62oC (

Enumeration was on plate count agar (PCA). 

 1:2a 1:3b 

Inoculated After After After Inoculated After After After Inoculated A

pretreated pretreated marinatedd dryinge pretreated pretreated marinatedd dryinge pretreated pret

Salmonella 8.50 6.71 6.26 <1.60f 8.50 7.02 6.46 <1.60 8.50 8

E. coli O157:H7 8.36 7.01 6.37 <1.60 8.36 7.14 6.87 <1.60 8.53 8

L. monocytogenes 8.55 7.44 6.81 <1.60 8.55 7.58 7.23 <1.60 8.55 8

a 1 part Mionix concentrate with 2 parts water, dipped for 30 secb 1 part Mionix concentrate with 3 parts water, dipped for 30 sec 

Dipped in tap water for 30 sec

d Marinade composed of: water, salt, sugar, vinegar, Worcestershire sauce, sodium erythorbatethrobate, MS

powder, sodium nitrite 

e Drying time approx 8-9 h; no humidity control f Enumeration below detection level; positive identification of organisms after enrichment 
c 

Antimicrobial Intervention and Process Validation in Beef Jerky Processing M. A. Harrison, R. K. Singh, J. A. Harrison, and N. Singh, University of Georgia Final Report Table 6. Survival of Salmonella, E. coli O157:H7, and L. monocytogenes (log cfu/strip) on marinated, w

pretreated with Mionix Safe2OTM (calcium sulfate) or not pretreated and dried in a smokehouse at 63oC 

of Salmonella, E. coli O157:H7, and L. monocytogenes was on bismuth sulfite agar (BSA), sorb(SMAC) and Listeria selective agar (LSA), respectively. 

 1:2a 1:3b 

Inoculated After After After Inoculated After After After Inoculated A

pretreated pretreated marinatedd dryinge pretreated pretreated marinatedd dryinge pretreated pret

Salmonella 8.43 6.67 6.32 <1.6f 8.43 6.79 6.51 <1.6 8.43 8

E. coli O157:H7 8.31 6.62 6.14 <1.6 8.31 6.75 6.61 <1.6 8.31 8

L. monocytogenes 8.52 7.16 6.52 <1.6 8.52 7.19 6.98 <1.6 8.52 8

a 1 part Mionix concentrate with 2 parts water, dipped for 30 secb 1 part Mionix concentrate with 3 parts water, dipped for 30 sec 

Dipped in tap water for 30 sec

d Marinade composed of: water, salt, sugar, vinegar, Worcestershire sauce, sodium erythorbatethrobate, MS

powder, sodium nitrite 

e Drying time approx 8-9 h; no humidity control f Enumeration below detection level; positive identification of organisms after enrichment 
c 

Antimicrobial Intervention and Process Validation in Beef Jerky Processing M. A. Harrison, R. K. Singh, J. A. Harrison, and N. Singh, University of Georgia Final Report Table 7. Survival of Salmonella, E. coli O157:H7, and L. monocytogenes (log cfu/strip) on marinated, whole stri

pretreated with Keeper® (chlorine dioxide) or not pretreated and dried in a smokehouse at 63°C (145oF)

on plate count agar (PCA). 

 Pretreatment Aa Pretreatment Bb 

Inoculated After After After Inoculated After After After Inoculated A

pretreated pretreated marinatedd dryinge pretreated pretreated marinatedd dryinge pretreated pret

Salmonella 8.54 7.77 7.10 <1.6f 8.54 8.17 7.31 2.23 8.54 8

E. coli O157:H7 8.53 7.73 7.05 <1.6 8.53 8.12 7.15 <1.6 8.53 8

L. monocytogenes 8.52 8.21 6.94 <1.6 8.52 8.32 7.31 <1.6 8.52 8

a Pretreatment A: 1,200 ppm ClO2 

b Pretreatment B: 500 ppm ClO2 

Dipped in tap water for 30 sec

d Marinade composed of: water, salt, sugar, vinegar, Worcestershire sauce, sodium erythorbatethrobate, MS

powder, sodium nitrite 

e Drying time approx 8-9 h; no humidity control f Enumeration below detection level; positive identification of organisms after enrichment 
c 

Antimicrobial Intervention and Process Validation in Beef Jerky Processing M. A. Harrison, R. K. Singh, J. A. Harrison, and N. Singh, University of Georgia Final Report Table 8. Survival of Salmonella, E. coli O157:H7, and L. monocytogenes (log cfu/strip) on marinated, whole stri

pretreated with Keeper® (chlorine dioxide) or not pretreated and dried in a smokehouse at 63°C (145oF)

Salmonella, E. coli O157:H7, and L. monocytogenes was on bismuth sulfite agar (BSA), sorbitol MacCand Listeria selective agar (LSA), respectively. 

 Pretreatment Aa Pretreatment Bb 

Inoculated After After After Inoculated After After After Inoculated A

pretreated pretreated marinatedd dryinge pretreated pretreated marinatedd dryinge pretreated pret

Salmonella 8.57 7.90 6.94 <1.6f 8.57 8.24 7.13 1.86 8.57 8

E. coli O157:H7 8.49 7.59 6.87 <1.60 8.49 8.02 7.01 <1.60 8.49 8

L. monocytogenes 8.49 7.79 6.83 <1.60 8.49 8.27 7.19 <1.60 8.49 8

a Pretreatment A: 1,200 ppm ClO2 

b Pretreatment B: 500 ppm ClO2 

Dipped in tap water for 30 sec

d Marinade composed of: water, salt, sugar, vinegar, Worcestershire sauce, sodium erythorbatethrobate, MS

powder, sodium nitrite 

e Drying time approx 8-9 h; no humidity control f Enumeration below detection level; positive identification of organisms after enrichment 
Antimicrobial Intervention and Process Validation in Beef Jerky Processing 

M. A. Harrison, R. K. Singh, J. A. Harrison, and N. Singh, University of Georgia 

Final Report 

Table 9. Average aw and pH value of marinated beef jerky that were pretreated with Mionix 

Safe2OTM (acidic calcium sulfate) or not pretreated and dried in horizontal dehydrator at 

62°C (143.6o

F). 

1:2a 1:3b Controlc 

aw pH aw pH aw pH 

Before pretreat. 1d 0.992 5.68 0.992 5.68 0.992 5.68 

2e 0.995 5.85 0.995 5.85 0.995 5.68 

3f 0.994 5.90 0.994 5.90 0.994 5.90 

After pretreated 1 0.994 4.55 0.995 4.74 0.994 5.72 

2 0.992 4.56 0.993 4.73 0.993 5.85 

3 0.994 4.63 0.994 4.76 0.995 5.94 

After marinatedg 1 0.982 4.55 0.982 4.70 0.982 5.30 

2 0.984 4.80 0.983 4.83 0.983 5.25 

3 0.983 4.63 0.984 4.78 0.983 5.09 

After dryingh 1 0.683 4.54 0.690 4.74 0.697 4.83 

2 0.680 4.61 0.683 4.68 0.681 4.90 

3 0.678 4.58 0.684 4.73 0.676 5.12 

Stored 1 mo. 1 0.678 4.97 0.686 5.15 0.679 5.50 

2 0.698 4.86 0.669 4.99 0.659 5.38 

3 0.681 4.83 0.706 4.99 0.686 5.37 

Stored 2 mo. 1 0.672 4.47 0.691 4.82 0.668 5.06 

2 0.682 4.77 0.668 4.93 0.692 5.46 

3 0.682 5.01 0.696 4.96 0.668 5.29 

Stored 3 mo. 1 0.679 4.80 0.692 4.95 0.694 5.22 

2 0.691 4.92 0.677 5.02 0.698 5.39 

3 0.678 4.88 0.693 4.96 0.675 5.38 a 1 part Mionix concentrate with 2 parts water, dipped for 30 sec

b 1 part Mionix concentrate with 3 parts water, dipped for 30 sec 

Dipped in tap water for 30 sec

d Result from the experiment with Salmonella e Result from the experiment with E. coli O157:H7 

f Result from the experiment with L. monocytogenes 

g Marinade composed of: water, salt, sugar, vinegar, Worcestershire sauce, sodium 

erythorbatethrobate, MSG, thyme, garlic powder, sodium nitrite 

h Drying time approx 8-9 h; no humidity control 

c 

16 
Antimicrobial Intervention and Process Validation in Beef Jerky Processing 

M. A. Harrison, R. K. Singh, J. A. Harrison, and N. Singh, University of Georgia 

Final Report 

Table 10. Average aw and pH value of marinated beef jerky that were pretreated with Keeper® 

(chlorine dioxide) or not pretreated and dried in horizontal dehydrator at 62°C 

(143.6o

F). 

 Pretreatment Aa Pretreatment Bb Controlc 

aw pH aw pH aw pH 

Before pretreat. 1d 0.997 5.92 0.997 5.92 0.997 5.92 

2e 0.993 5.89 0.993 5.89 0.993 5.89 

3f 0.994 5.84 0.994 5.84 0.994 5.84 

After pretreated 1 0.995 5.83 0.995 5.81 0.994 5.90 

2 0.993 5.53 0.995 5.57 0.995 5.85 

3 0.996 5.60 0.994 5.74 0.995 5.78 

After marinatedg 1 0.984 5.08 0.982 5.26 0.983 5.19 

2 0.984 5.06 0.984 5.19 0.983 4.98 

3 0.983 5.05 0.984 5.05 0.983 5.01 

After dryingh 1 0.685 5.11 0.681 5.03 0.687 5.36 

2 0.690 5.05 0.683 5.07 0.706 4.99 

3 0.695 5.02 0.674 5.11 0.689 5.11 

Stored 1 mo. 1 0.708 5.19 0.698 5.22 0.704 5.38 

2 0.704 5.31 0.692 5.37 0.689 5.68 

3 0.762 5.26 0.656 5.28 0.678 5.33 

Stored 2 mo. 1 0.708 5.13 0.704 5.01 0.718 5.25 

2 0.692 5.32 0.674 5.33 0.693 5.27 

3 0.674 5.21 0.659 5.21 0.676 5.14 

Stored 3 mo. 1 0.700 5.14 0.704 5.08 0.709 5.22 

2 0.687 5.26 0.710 5.16 0.728 5.05 

3 0.691 5.10 0.605 5.08 0.694 5.14 a Pretreatment A: 1,200 ppm ClO2 

b Pretreatment B: 500 ppm ClO2 

Dipped in tap water for 30 sec

d Result from the experiment with Salmonella e Result from the experiment with E. coli O157:H7 

f Result from the experiment with L. monocytogenes 

g Marinade composed of: water, salt, sugar, vinegar, Worcestershire sauce, sodium 

erythorbatethrobate, MSG, thyme, garlic powder, sodium nitrite 

h Drying time approx 8-9 h; no humidity control 

c 

17 
c 

Antimicrobial Intervention and Process Validation in Beef Jerky Processing 

M. A. Harrison, R. K. Singh, J. A. Harrison, and N. Singh, University of Georgia 

Final Report 

Table 11. Water activity aw and pH value of marinated beef jerky that were pretreated with 

Mionix Safe2OTM (acidic calcium sulfate) or not pretreated and dried in smokehouse at 

63°C (145o

F). 

Before pretreat. 

After pretreated 

After marinatedd 

1:2a 

aw pH 

0.990 

0.990 

0.979 

5.52 

4.39 

4.45 

1:3b 

aw pH 

0.990 

0.991 

0.982 

5.52 

4.63 

4.55 

Controlc 

aw pH 

0.990 5.52 

0.993 5.52 

0.981 5.03 

After dryinge 

Stored 1 mo. 

0.677 

0.695 

4.58 

4.62 

0.697 

0.677 

4.81 

4.83 

0.667 

0.647 

5.08 

4.88 

Stored 2 mo. 0.647 4.72 0.657 4.75 0.657 4.94 

Stored 3 mo. 0.676 4.89 0.652 4.75 0.657 5.03 

a 1 part Mionix concentrate with 2 parts water, dipped for 30 sec

b 1 part Mionix concentrate with 3 parts water, dipped for 30 sec 

Dipped in tap water for 30 sec

d Marinade composed of: water, salt, sugar, vinegar, Worcestershire sauce, sodium 

erythorbatethrobate, MSG, thyme, garlic powder, sodium nitrite e Drying time approx 8-9 h; no humidity control 

18 
c 

Antimicrobial Intervention and Process Validation in Beef Jerky Processing 

M. A. Harrison, R. K. Singh, J. A. Harrison, and N. Singh, University of Georgia 

Final Report 

Table 12. Water activity aw and pH value of marinated beef jerky that were pretreated with 

Keeper® (chlorine dioxide) or not pretreated and dried in smokehouse at 62°C 

(145o

F). 

Pretreatment Aa Pretreatment Bb Controlc 

aw pH aw pH aw pH 

Before pretreat. 0.995 5.94 0.995 5.94 0.995 5.94 

After pretreated 0.997 5.76 0.997 5.96 0.998 5.76 

After marinatedd 0.985 5.07 0.984 5.08 0.985 5.05 

After dryinge 0.661 5.04 0.665 5.13 0.675 5.09 

Stored 1 mo. 0.676 5.03 0.671 5.15 0.658 5.24 

Stored 2 mo. 0.655 5.01 0.664 5.32 0.661 5.22 

Stored 3 mo. 0.651 5.24 0.642 5.27 0.649 5.40 

a Pretreatment A: 1,200 ppm ClO2 

b Pretreatment B: 500 ppm ClO2 

Dipped in tap water for 30 sec

d Marinade composed of: water, salt, sugar, vinegar, Worcestershire sauce, sodium 

erythorbatethrobate, MSG, thyme, garlic powder, sodium nitrite e Drying time approx 8-9 h; no humidity control 

19