Modelling growth of Escherichia coli O157:H7 in fresh-cut lettuce submitted to commercial process conditions: Chlorine washing and modified atmosphere packaging

Fresh-cut iceberg lettuce inoculated with Escherichia coli O157:H7 was submitted to chlorine washing (150 mg/mL) and modified atmosphere packaging on laboratory scale. Populations of E. coli O157:H7 were assessed in fresh-cut lettuce stored at 4, 8, 13 and 16 °C using 6–8 replicates in each analysis point in order to capture experimental variability. The pathogen was able to grow at temperatures ≥8 °C, although at low temperatures, growth data presented a high variability between replicates. Indeed, at 8 °C after 15 days, some replicates did not show growth while other replicates did present an increase. A growth primary model was fitted to the raw growth data to estimate lag time and maximum growth rate. The prediction and confidence bands for the fitted growth models were estimated based on Monte-Carlo method. The estimated maximum growth rates (log cfu/day) corresponded to 0.14 (95% CI: 0.06–0.31), 0.55 (95% CI: 0.17–1.20) and 1.43 (95% CI: 0.82–2.15) for 8, 13 and 16 °C, respectively. A square-root secondary model was satisfactorily derived from the estimated growth rates (R² > 0.80; Bf = 0.97; Af = 1.46). Predictive models and data obtained in this study are intended to improve quantitative risk assessment studies for E. coli O157:H7 in leafy green products.     

Mathematical modeling the cross-contamination of Escherichia coli O157:H7 on the surface of ready-to-eat meat product while slicing

Microbial cross-contamination either at home or production site is one of the major factors of causing contamination of foods and leading to the foodborne illness. The knowledge regarding Escherichia coli O157:H7 surface transfer on ready-to-eat (RTE) deli meat and the slicer used for slicing different RTE products are needed to ensure RTE food safety. The objectives of this study were to investigate and to model the surface cross-contamination of E. coli O157:H7 during slicing operation. A five-strain cocktail of E. coli O157:H7 was inoculated directly onto a slicer's round blade rim area at an initial level of ca. 4, 5, 6, 7 or 8 log CFU/blade (ca. 3, 4, 5, 6 or 7 log CFU/cm² of the blade edge area), and then the RTE deli meat (ham) was sliced to a thickness of 1–2 mm. For another cross-contamination scenario, a clean blade was initially used to slice ham which was pre-surface-inoculated with E. coli O157:H7 (ca. 4, 5, 6, 7 or 8 log CFU/100 cm² area), then, followed by slicing un-inoculated ham. Results showed that the developed empirical models were reasonably accurate in describing the transfer trend/pattern of E. coli O157:H7 between the blade and ham slices when the total inoculum level was ≥5 log CFU on the ham or blade. With an initial inoculum level at ≤4 log CFU, the experimental data showed a rather random microbial surface transfer pattern. The models, i.e., a power equation for direct-blade-surface-inoculation, and an exponential equation for ham-surface-inoculation are microbial load and sequential slice index dependent. The surface cross-contamination prediction of E. coli O157:H7 for sliced deli meat (ham) using the developed models were demonstrated. The empirical models may provide a useful tool in developing the RTE meat risk assessment.     

Salmonella, Escherichia coli O157:H7 and E. coli biotype 1 in a pilot survey of imported and New Zealand pig meats

A pilot survey for the pathogens Salmonella and Escherichia coli O157:H7, and E. coli biotype 1 was conducted on 100 New Zealand-produced (domestic) pig carcasses and 110 imported pig meat samples over an 8-month period to assess the likelihood of introduction of novel pathogen strains into New Zealand (NZ), and as a guide for development of a domestic pork National Microbiological Database programme. Salmonella was not isolated from domestic pig carcasses or from pig meat imported from Canada and the USA. The prevalence of Salmonella in imported pig meat was 3.6% (95% CI 1.0–9.0) with positive samples detected from Australian pig meat. The prevalence of E. coli O157:H7 on domestic pig carcasses was 1% (95% CI 0.03–5.4) while the overall prevalence of E. coli O157:H7 in imported pig meat was 1.8% (95% CI 0.2–6.4), detected mainly from Australian but not from Canadian or US pork. All except three samples have an E. coli biotype 1 count of <100 CFU cm⁻² or g⁻¹, indicating good hygiene quality of domestic and imported pig meat. The results demonstrated that importation of uncooked pig meat is a potential route for the introduction of new clones of Salmonella and E. coli O157:H7 into New Zealand.     

Adaptation of Escherichia coli O157:H7 to acid in traditional and commercial goat milk amasi

Acid resistance of Escherichia coli O157:H7 strains UT 10 and UT 15 were determined in traditional Amasi fermented for 3 days at ambient temperature (ca 30 °C) and commercial Amasi fermented at 30 °C for 24 h and stored at 7 °C for 2 days. Escherichia coli O157:H7 counts in commercial Amasi were detected at 2.7 log₁₀ cfu/ml after 3 days while those in traditional Amasi could not be detected after the same period. There was no significant difference (p ? 0.05) in the survival of acid adapted (AA) and non-adapted (NA) E. coli O157:H7 in traditional Amasi, while in commercial Amasi, the NA strain survived significantly (p ? 0.05) better than its AA counterpart. Regardless of prior adaptation to acid, E. coli O157:H7 can survive during fermentation and storage of fermented goat milk Amasi. Also, the fermentation time, pH and storage temperature affects the survival of E. coli O157:H7 in the fermented milk.     

A simplified method for numerical simulation of gas grilling of non-intact beef steaks to eliminate Escherichia coli O157:H7

The objective of this work was to develop a numerical simulation method to study the heat transfer process and inactivation of Escherichia coli O157:H7 during gas grilling of non-intact beef steaks (NIBS). A finite difference and optimization algorithm was developed to determine the effective heat transfer parameters during grilling. After validation, these parameters were used in a finite element method to simulate the temperature profiles at various locations of NIBS (2.54 cm in thickness). The computer simulation results showed that E. coli O157:H7 may survive the heating processes if normal grilling conditions for intact beef steaks were used. Computer simulation results also suggested that E. coli O157:H7 might be effectively inactivated if NIBS (2.54 cm) were evenly flipped (every 4 min) and cooked for 16 min during cooking. The result of this study may help the food service industry to develop more adequate grilling methods and conditions to cook NIBS.     

Fate of Escherichia coli O157:H7 in field-inoculated lettuce

Impact of drip and overhead sprinkler irrigation on the persistence of attenuated Escherichia coli O157:H7 in the lettuce phyllosphere was investigated using a split-plot design in four field trials conducted in the Salinas Valley, California, between summer 2007 and fall 2009. Rifampicin-resistant attenuated E. coli O157:H7 ATCC 700728 (BLS1) was inoculated onto the soil beds after seeding with a backpack sprayer or onto 2- or 4-week-old lettuce plant foliage with a spray bottle at a level of 7 log CFU ml⁻¹. When E. coli O157:H7 was inoculated onto 2-week-old plants, the organism was recovered by enrichment in 1 of 120 or 0 of 240 plants at 21 or 28 days post-inoculation, respectively. For the four trials where inoculum was applied to 4-week-old plants, the population size of E. coli O157:H7 declined rapidly and by day 7, counts were near or below the limit of detection (10 cells per plant) for 82% or more of the samples. However, in 3 out 4 field trials E. coli O157:H7 was still detected in lettuce plants by enrichment 4-weeks post-inoculation. Neither drip nor overhead sprinkler irrigation consistently influenced the survival of E. coli O157:H7 on lettuce.     

Effects of cooking methods and chemical tenderizers on survival of Escherichia coli O157:H7 in ground beef patties

This study evaluated chemical tenderizers and cooking methods to inactivate Escherichia coli O157:H7 in ground beef patties (model system for non-intact beef). Ground beef was inoculated with E. coli O157:H7 and mixed with (i) nothing (control), (ii) calcium chloride (CC) and flavoring agents (FA), (iii) CC, FA, and acetic acid (AA), (iv) sodium chloride (SC), sodium tripolyphosphate (ST), and potassium lactate (PL), and (v) the combination of SC, ST, PL, and AA. Patties were stored in aerobic or vacuum bags at − 20, 4, and 12 °C. Samples were grilled, broiled, or pan-fried to 60 or 65 °C. Total bacterial and E. coli O157:H7 populations remained unchanged during storage. Broiling was more effective in reducing E. coli O157:H7 than grilling and pan-frying, and acidified tenderizers reduced E. coli O157:H7 more than non-acidified tenderizers in broiling. Higher reductions were observed at 65 °C than 60 °C in broiled and grilled samples. These results indicate that acidified tenderizers and broiling may be useful in non-intact beef safety.     

Survival of Escherichia coli O157:H7 in channel catfish pond and holding tank water

Survival of Escherichia coli O157:H7 in channel catfish (Ictalurus punctatus), pond and holding tank water was investigated. Water from three channel catfish ponds was inoculated with ampicillin/nalidixic acid-resistant E. coli O157:H7 transformed with a plasmid encoding for green fluorescent protein at 10⁵, 10⁶, and 10⁷ CFU/ml. Samples were taken from surface, internal organs, and skin scrape of fish and pond water for E. coli O157:H7 enumeration on brain heart infusion (BHI) agar containing ampicillin and nalidixic acid. To determine the survival of E. coli O157:H7 in catfish holding tank water from two farmers markets, the water was inoculated with 10⁷E. coli O157:H7 CFU/ml. E. coli O157:H7 were detected by direct plating for 33 and 69 d in pond and holding tank water, respectively. A rapid decrease of the pathogen was observed in the first 2 weeks to reach 2 log CFU/ml. When E. coli O157:H7 was not recovered by direct plating, the pathogen was isolated by enrichment in TSB for approximately another 30 d from pond and holding tank water. The populations of E. coli O157:H7 found in the internal organs and skin scrape were 5.5 log and 2.5 log CFU/ml, respectively. E. coli O157:H7 from internal organs and water were recovered for at least 12 d. Results suggest that E. coli O157:H7 can survive in channel catfish pond and holding tank water and channel catfish may become a potential carrier of the pathogen.     

Quantification of contamination of lettuce by GFP-expressing Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium

The primary objective of this study was to determine the possibility of internalization of GFP-expressing Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium (S. Typhimurium) strains MAE 110 (multi-cellular morphology) and 119 (wild type morphology) into lettuce seedlings (Lactuca sativa cv. Tamburo) grown in an inoculated hydroponic and soil system. The second aim was to quantify the level of contamination with the use of a proper surface sterilization method. Silver nitrate was superior in reducing the number of viable bacteria on leave surfaces compared to sodium hypochlorite and ethanol. With the hydroponic system internal colonization of lettuce only occurred at high densities with S. Typhimurium MAE 119. With the soil system E. coli O157:H7, S. Typhimurium 110 and S. Typhimurium 119 were found at considerable densities in sterilized leaf samples (respectively, 3.95, 2.57 and 2.37 log cfu/g on average) with prevalences of 0.29, 0.23 and 0.15, respectively. No statistical differences were observed between the Salmonella strains. A negative correlation was observed between shoot weight and leaf contamination. The observed presence of the pathogens in lettuce, after thorough surface sterilization, demonstrates the possible presence of human pathogens in locations were they are unlikely to be removed by the actions of consumer washing and therefore pose a serious threat when occurring in field situations.     

Enhancing the thermal destruction of Escherichia coli O157:H7 in ground beef patties by trans-cinnamaldehyde

The effect of trans-cinnamaldehyde (TC) on the inactivation of Escherichia coli O157:H7 in undercooked ground beef patties was investigated. A five-strain mixture of E. coli O157:H7 was inoculated into ground beef (7.0 log CFU/g), followed by addition of TC (0, 0.15, and 0.3%). The meat was formed into patties and stored at 4 °C for 5 days or at −18 °C for 7 days. The patties were cooked to an internal temperature of 60 or 65 °C, and E. coli O157:H7 was enumerated. The numbers of E. coli O157:H7 did not decline during storage of patties. However, cooking of patties containing TC significantly reduced (P < 0.05) E. coli O157:H7 counts, by >5.0 log CFU/g, relative to the reduction in controls cooked to the same temperatures. The D-values at 60 and 65 °C of E. coli O157:H7 in TC-treated patties (1.85 and 0.08 min, respectively) were significantly lower (P < 0.05) than the corresponding D-values for the organism in control patties (2.70 and 0.29 min, respectively). TC-treated patties were more color stable and showed significantly lower lipid oxidation (P < 0.05) than control samples. TC enhanced the heat sensitivity of E. coli O157:H7 and could potentially be used as an antimicrobial for ensuring pathogen inactivation in undercooked patties. However detailed sensory studies will be necessary to determine the acceptability to consumers of TC in ground beef patties.     

The prevalence of Escherichia coli O157 and O157:H7 in ground beef and raw meatball by immunomagnetic separation and the detection of virulence genes using multiplex PCR

The present study was conducted to investigate the presence of Escherichia coli O157 and O157:H7 strains and to detect the presence of the stx1, stx2, and eaeA genes in isolates derived from 200 samples (100 samples from fresh ground beef and 100 samples from raw meatball). The samples were purchased from the Samsun Province in Turkey, over a period of 1 year. Enrichment-based immunomagnetic separation and multiplex polymerase chain reaction were applied for these analyses. E. coli O157 was detected in five of the 200 (2.5%) samples tested (one isolated from ground beef and four from meatball samples), whereas E. coli O157: H7 was not detected in any sample. During the analysis, eight strains of E. coli O157 were obtained. The genes stx1, stx2, and eaeA were detected in two E. coli O157 isolates obtained from two meatball samples, whereas only the eaeA and the stx2 genes were detected in four E. coli O157 strains that were isolated from one meatball sample. None of the stx1, stx2, and eaeA was detected in the E. coli O157 isolates obtained from the ground beef and the one meatball samples.     

Fate of Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella on fresh-cut celery

Illnesses from Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella have been associated with the consumption of numerous produce items. Little is known about the effect of consumer handling practices on the fate of these pathogens on celery. The objective of this study was to determine pathogen behavior at different temperatures under different storage conditions. Commercial fresh-cut celery was inoculated at ca. 3 log CFU/g onto either freshly cut or outer uncut surfaces and stored in either sealed polyethylene bags or closed containers. Samples were enumerated following storage for 0, 1, 3, 5, and 7 days when held at 4 °C or 12 °C, and after 0, 8, and 17 h, and 1, and 2 days when held at 22 °C. At 4 °C, all populations declined by 0.5–1.0 log CFU/g over 7 days. At 12 °C, E. coli O157:H7 and Salmonella populations did not change, while L. monocytogenes populations increased by ca. 0.5 log CFU/g over 7 days. At 22 °C, E. coli O157:H7, Salmonella, and L. monocytogenes populations increased by ca. 1, 2, or 0.3 log CFU/g, respectively, with the majority of growth occurring during the first 17 h. On occasion, populations on cut surfaces were significantly higher than those on uncut surfaces. Results indicate that populations are reduced under refrigeration, but survive and may grow at elevated temperatures.     

ß-phenylethylamine as a novel nutrient treatment to reduce bacterial contamination due to Escherichia coli O157:H7 on beef meat

Bacterial infection by Escherichia coli O157:H7 through the consumption of beef meat or meat products is an ongoing problem, in part because bacteria develop resistances towards chemicals aimed at killing them. In an approach that uses bacterial nutrients to manipulate bacteria into behaviors or cellular phenotypes less harmful to humans, we screened a library of 95 carbon and 95 nitrogen sources for their effect on E. coli growth, cell division, and biofilm formation. In the initial screening experiment using the Phenotype MicroArray^TM technology from BioLog (Hayward, CA), we narrowed the 190 starting nutrients down to eight which were consecutively tested as supplements in liquid beef broth medium. Acetoacetic acid (AAA) and ß-phenylethylamine (PEA) performed best in this experiment. On beef meat pieces, PEA reduced the bacterial cell count by 90% after incubation of the PEA treated and E. coli contaminated meat pieces at 10 °C for one week.     

Inactivation of Salmonella and Escherichia coli O157:H7 on artificially contaminated alfalfa seeds using high hydrostatic pressure

Alfalfa sprouts contaminated with Salmonella and Escherichia coli O157:H7 have been implicated in several outbreaks of foodborne illnesses in recent years. The seed used for sprouting appears to be the primary source of pathogens. Seed decontamination prior to sprouting presents a unique challenge for the sprouting industry since cells of the pathogenic survivors although undetectable after sanitizing treatments, can potentially multiply back to hazardous levels. The focus of this study was to therefore test the efficacy of high hydrostatic pressure to eliminate a ∼5 log CFU/g load of Salmonella and E. coli O157:H7 on alfalfa seeds. Pressure treatment of 600 MPa for up to 25 min at 20 °C could not result in complete inactivation of Salmonella. High-pressure treatment was then carried out either at sub-ambient (4 °C) or elevated (40, 45 and 50 °C) temperatures to test the ability of high pressure to eliminate Salmonella. Pressure treatment at 4 and 20 °C did not deliver any satisfactory inactivation of Salmonella while high pressure at elevated temperatures achieved complete kill. Pre-soaking seeds prior to high-pressure treatment also enhanced pressure inactivation of Salmonella but at the expense of seed viability. High-pressure treatment of 500 MPa for 2 min at 45 °C was able to eliminate wild-type Salmonella and E. coli O157:H7 strains without bringing about any appreciable decrease in the seed viability.     

Inactivation of Escherichia coli O157:H7 on stainless steel upon exposure to Paenibacillus polymyxa biofilms

We investigated the potential use of biofilm formed by a competitive-exclusion (CE) microorganism to inactivate Escherichia coli O157:H7 on a stainless steel surface. Five microorganisms showing inhibitory activities against E. coli O157:H7 were isolated from vegetable seeds and sprouts. The microorganism with the greatest antimicrobial activity was identified as Paenibacillus polymyxa (strain T5). In tryptic soy broth (TSB), strain T5 reached a higher population at 25 °C than at 12 or 37 °C without losing inhibitory activity against E. coli O157:H7. When P. polymyxa (6 log CFU/mL) was co-cultured with E. coli O157:H7 (2, 3, 4, or 5 log CFU/mL) in TSB at 25 °C, the number of E. coli O157:H7 decreased significantly within 24 h. P. polymyxa formed a biofilm on stainless steel coupons (SSCs) in TSB at 25 °C within 24 h, and cells in biofilms, compared to attached cells without biofilm formation, showed significantly increased resistance to a dry environment (43% relative humidity [RH]). With the exception of an inoculum of 4 log CFU/coupon at 100% RH, upon exposure to biofilm formed by P. polymyxa on SSCs, populations of E. coli O157:H7 (2, 4, or 6 log CFU/coupon) were significantly reduced within 48 h. Most notably, when E. coli O157:H7 at 2 log CFU/coupon was applied to SSCs on which P. polymyxa biofilm had formed, it was inactivated within 1 h, regardless of RH. These results will be useful when developing strategies using biofilms produced by competitive exclusion microorganisms to inactivate foodborne pathogens in food processing environments.     

Prevalence and antimicrobial susceptibility of Escherichia coli O157:H7 on beef cattle slaughtered in Amman abattoir

Cattle are the main asymptomatic reservoir of Escherichia coli O157:H7 which can cause illness to human. The objectives of the study were to measure the prevalence of E. coli O157:H7 on cattle slaughtered in Amman abattoir, detect virulence factors in the isolates, determine antibacterial resistance of the isolates, and know how the isolates are different or similar when compared to characterized isolates from developed countries.     

The growth,survival and thermal inactivation of Escherichia coli O157:H7 in a traditional South African sausage

This study investigated the growth and survival of Escherichia coli O157:H7 inoculated into boerewors models with (B + P) and without (B − P) sulphur dioxide preservative at a low (L) and high (H) inoculum followed by storage at 0, 4 and 10 °C for 10 days. The pathogen’s thermal inactivation at 50, 60, 65 and 70 °C was also evaluated in B + P. The B − P at both low and high inocula had significantly higher recoveries at all temperatures compared to B + P. The BL + P and BH + P had significant reductions in recoveries at 0 °C, declining to below detectable limits at days 8 and 10, respectively. At 4 °C, the BL + P and BH + P recoveries declined significantly at day 10. At 10 °C, significant increases were observed from days 0 to day 10 in both models and at low and high inocula. At 0 °C, the BL − P and BH − P treatments had significant declines in recoveries. The combination of sulphur dioxide preservative and low temperature demonstrated the best efficacy against E. coli O157:H7 survival. Thermal inactivation of E. coli O157:H7 was 60 min at 60 °C, 80 s at 65 °C and 60 s at 70 °C. This study demonstrated that E. coli O157:H7 can survive in boerewors with and without preservative and is more sensitive to heat treatment at 70 °C.     

Control of Escherichia coli O157:H7 in corn silage with or without various inoculants: Efficacy and mode of action

This study aimed to evaluate the effectiveness of 3 commercial bacterial inoculants at controlling Escherichia coli O157:H7 in corn silages during ensiling and feedout phases of silage production. A second objective was to determine whether the inoculants exhibited and transferred antibacterial activity against E. coli O157:H7 to the silages. Chopped corn forage was ensiled after treatment with the following: distilled water (control); 5 × 10⁵ cfu/g of E. coli O157:H7 (EC); EC and 1 × 10⁶ cfu/g of Pediococcus pentosaceus and Propionibacterium freudenreichii (EC+BII); EC and 1 × 10⁶ cfu/g of Lactobacillus buchneri (EC+LB); and EC and 1 × 10⁶ cfu/g of L. buchneri and P. pentosaceus (EC+B500). Each treatment was ensiled in triplicate in mini silos for 3, 7, 31, and 82 d and analyzed for pH and E. coli O157:H7 counts. Samples from d 82 were also analyzed for volatile fatty acids, lactate, and aerobic stability. Antibacterial activity of inoculants and silages was determined by the Kirby-Bauer disc diffusion test. The pH of silages from all treatments decreased below 4 within 3 d of ensiling and remained low until d 82. Therefore, E. coli O157:H7 was not detected in silages after any of the ensiling durations. Applying inoculants containing L. buchneri resulted in less lactate, more acetate, and greater aerobic stability compared with the control. Applying EC+BII containing P. freudenreichii did not increase propionate or aerobic stability. Subsamples of d 82 silages were reinoculated with 1 × 10⁵ cfu/g of E. coli O157:H7 either immediately after silo opening on d 82 or after 144 h of aerobic exposure (d 88), and E. coli were enumerated 24 h later. All silages reinoculated with the pathogen on d 82 had similar, low pH values (<4) and no E. coli were detected 24 h later. Control, EC, and EC+BII silages reinoculated with the pathogen after 144 h of aerobic exposure had relatively greater pH values (4.71, 5.67, and 6.03, respectively) and E. coli counts (2.87, 6.73, and 6.87 log cfu/g, respectively) 24 h later, whereas those treated with L. buchneri had low pH values (<4) and undetectable (EC+B500) or 10-fold lower (1.97, cfu/g; EC+LB) E. coli counts. All pure cultures of commercial bacterial inoculants exhibited antibacterial activity independent of pH against E. coli O157:H7, but the pH-independent activity did not persist in the treated silages, suggesting that E. coli elimination from silages was mediated by pH reduction.     

Super shedding of Escherichia coli O157:H7 by cattle and the impact on beef carcass contamination

Beef carcass contamination is a direct result of pathogen transfer from cattle hides harboring organisms such as enterohemorrhagic Escherichia coli. Hide contamination occurs from direct and indirect fecal contamination in cattle production and lairage environments. In each of these environments, individual animals shedding E. coli O157:H7 at high levels (> 10⁴ CFU/g of feces, hereafter referred to as “super shedders”) can have a disproportionate effect on cattle hide and subsequent carcass contamination. It is not known what criteria must be met to cause an animal to shed at levels exceeding 10⁴ CFU/g. Understanding the factors that play a role in super shedding will aid in minimizing or eliminating the super shedding population. Interventions that would prevent supershedding in the cattle population should reduce E. coli O157:H7 transmission in the production and lairage environments resulting in reduced risk of beef carcass contamination and a safer finished product.     

Inhibition of Listeria monocytogenes and Escherichia coli O157:H7 in liquid broth medium and during processing of fermented sausage using autochthonous starter cultures

The antimicrobial effect of two autochthonous starter cultures of Lactobacillus sakei was evaluated in vitro (in liquid broth medium) and in situ assays. The inactivation of foodborne pathogens Listeria monocytogenes (serotype 4ab No 10) and Escherichia coli O157:H7 ATCC 43888 was investigated during the production of fermented sausage according to a typical Greek recipe using L. sakei strains as starter cultures. The inactivation kinetics were modeled using GInaFiT, a freeware tool to assess microbial survival curves. By the end of the ripening period, the inhibition of L. monocytogenes was significant in treatments with L. sakei 8416 and L. sakei 4413 compared to the control treatment. A 2.2-log reduction of the population of E. coli O157:H7 resulted from the autochthonous starter culture L. sakei 4413 during sausage processing. The use of the autochthonous starter cultures constitutes an additional improvement to the microbial safety by reducing foodborne pathogens.