Heat-inactivated Cells Research Articles

Enhanced biosorptive removal of cadmium from aqueous solutions by silicon dioxide nano-powder, heat inactivated and immobilized Aspergillus ustus

Heat inactivated Aspergillus ustus (Asp), silicon dioxide-nano-powder (N―Si), and silicon dioxide nano-powder-combined-heat inactivated Aspergillus ustus (N―Si―Asp) were used to study the biosorption of Cd(II) from aqueous solutions via batch equilibrium technique. Surface characterization and immobilization of the fungal cells on silicon dioxide-nano-powder were examined and confirmed by using FT-IR and ESM analysis. Cadmium biosorption processes were investigated under the effect of pH, contact time, sorbent dosage and initial metal concentration. The three examined sorbents were found to exhibit maximum μmol g -1 capacity values in pH 7.0. The maximum determined cadmium capacity by silicon dioxide-nano-powder (N―Si) (600 μmol g − 1 ) was found higher than that exhibited by the heat inactivated fungal cells (Asp) (400 μmol g − 1 ). However, (N―Si―Asp) exhibited the highest sorption cadmium capacity (1000 μmol g − 1 ) as a combined behavior of both silicon dioxide nano-powder and Aspergillus ustus units. Sorption equilibria were established in 20 min and their data were well described by both Langmuir and Freundlich models. The potential applications of these sorbents for biosorptive removal of Cd(II) from real samples contaminated with cadmium, were successfully accomplished via a micro-column under constant flow rate.

Impact of fluorides on the removal of heavy metals from an electroplating effluent using a flocculent brewer’s yeast strain of Saccharomyces cerevisiae

Besides several toxic heavy metals, electroplating effluents can have in solution different cations and anions, which may influence heavy metals removal by the biomass. Among them, fluorides are commonly used in the electroplating industries and thus can be found in the respective wastewaters. In the present work, the effect of the presence of fluorides in the efficiency of chromium(III), copper(II) and nickel(II) removal, from an effluent, by heat-inactivated cells of a brewing flocculent strain of Saccharomyces cerevisiae was evaluated. The presence of fluorides severely decreased (>60%) the removal of chromium(III) by yeast biomass. This effect impaired the effective treatment of the effluent according to the US Environmental Protection Agency and the Portuguese law; conversely, a higher removal of copper(II) and nickel(II) was observed. This behaviour can be understood by metal speciation. In the presence of fluorides, chromium(III) was mainly complexed, becoming unavailable for yeast accumulation; this effect decreased the efficiency of chromium(III) removal. Thus, in the presence of fluorides, less chromium(III) is associated with biomass and consequently more yeast binding sites remain available for the uptake of other metals present in solution. This fact explains the increase of copper(II) and nickel(II) removal in the presence of fluorides.

Biosorption of copper by wine-relevant lactobacilli

Must and wine may be contaminated with elevated copper concentrations by the use of fungicides or in course of the vinification process. Hitherto only a few practicable and harmless procedures exist to reduce an excess of copper from must and wine. For this reason we investigated the biosorption of copper by eight wine-relevant Lactobacillus species. Both, living and heat-inactivated cells revealed a significant degree of Cu adsorption. It was shown that Cu binding correlated positively with an increasing pH value of the environment. The highest binding capacity of the tested lactic acid bacteria was found for L. buchneri DSM 20057 with a maximum of 46.17 μg Cu bound per mg cell in deionized water. In must, wine and grape juice Cu was removed less effective which is not solely attributed to low pH-values, but also to specific medium parameters such as intrinsic metal cations, organic acids or phenolic compounds. Nevertheless, about 0.5–1.0 μg Cu per ml could be removed from wine samples, which is sufficient enough to lower critical copper concentrations.

Removal of Chromium, Copper, and Nickel from an Electroplating Effluent Using a Flocculent Brewer’s Yeast Strain of Saccharomyces cerevisiae

The release of heavy metals in aquatic systems due to the discharge of industrial wastewaters is a matter of environmental concern. Heat-inactivated cells of a flocculent strain of Saccharomyces cerevisiae were used in the bioremediation, in a batch mode, of a real electroplating effluent containing Cu, Ni, and Cr. In this approach, no previous reduction of Cr(VI) to Cr(III) was required. Cr(VI) was selectively removed (98%) by yeast biomass at pH 2.3. At this pH, Cr(VI) is mainly in the form of HCrO4− and yeast surface is surrounded by H+ ions, which enhance the Cr(VI) interaction with biomass binding sites by electrostatic forces. Subsequently, pH of the effluent was raised up to 6.0; this pH maximizes the efficiency of cations removal since at this pH the main binding groups of yeast cells are totally or partially deprotonated. The passage of effluent through a series of sequential batches, at pH 6.0, allowed, after the third batch, the removal of Cu(II), Ni (II), Cr total, and Cr(VI) in the effluent to values below the legal limit of discharge. The strategy proposed in the present work can be used in plants for the treatment of heavy metals rich industrial effluents containing simultaneously Cr(VI) and Cr(III).

Biosorption of zinc ions from aqueous solution by the microalga Scenedesmus obliquus

Aquatic environments are often exposed to toxic heavy metals, which gain access to the food chain via microalgae and may cause severe problems at higher trophic levels. However, such a metabolic specificity can be taken advantage of in bioremediation strategies. The potential of a novel wild strain of Scenedesmus obliquus, previously isolated from a heavy metal-contaminated site in northern Portugal, to remove Zn from aqueous solutions was thus studied, using several initial concentrations. The removal extent reached its maximum by 1 day: 836.5 mg Zn/g biomass, at the initial concentration of 75 mg/L, mainly by adsorption onto the cell surface. Comparative studies encompassing a commercially available strain of the same microalgal species led to a maximum removal extent of only 429.6 mg Zn/g biomass, under identical conditions. Heat-inactivated cells permitted a maximum removal of 209.6 mg Zn/g biomass, at an initial concentration of 50 mg Zn/L. The maximum adsorption capacity of Zn, estimated via Langmuir’s isotherm, was 330 mg Zn/g biomass. Finally, Zn removal was highest at pH 6.0–7.0. It was proven, for the first time, that such a wild microalga can uptake and adsorb Zn very efficiently, which unfolds a particularly good potential for bioremediation. Its performance is far better than similar (reference) species, especially near neutrality, and even following heat-treatment.

Proteomics of RAW 264.7 macrophages upon interaction with heat‐inactivated Candida albicans cells unravel an anti‐inflammatory response

Murine macrophages (RAW 264.7) were allowed to interact with heat-inactivated cells of Candida albicans SC5314 during 45 min. The proteomic response of the macrophages was then analyzed using 2-D gel electrophoresis. Many proteins having differential expression with respect to control macrophages were identified, and their functions were related to important processes, such as cytoskeletal organization, signal transduction, metabolism, protein biosynthesis, stress response and protein fate. Several of these proteins have been described as being involved in the process of inflammation, such as Erp29, Hspa9a, AnxaI, Ran GTPase, P4hb, Clic1 and Psma1. The analysis of the consequences of their variation unravels an overall anti-inflammatory response of macrophages during the interaction with heat-inactivated cells. This result was corroborated by the measurement of TNF-alpha and of ERK1/2 phosphorylation levels. This anti-inflammatory effect was contrary to the one observed with live C. albicans cells, which induced higher TNF-alpha secretion and higher ERK1/2 phosphorylation levels with respect to control macrophages.

Use of the microalga Scenedesmus obliquus to remove cadmium cations from aqueous solutions

The ability of a wild strain of Scenedesmus obliquus, isolated from a heavy metal-contaminated environment, to remove Cd2+ from aqueous solutions was studied at several initial concentrations. Viable biomass removed metal to a maximum extent of 11.4 mgCd/g at 1 mgCd/l, with most Cd2+ being adsorbed onto the cell surface. A commercially available strain (ACOI 598) of the same microalga species was also exposed to the same Cd concentrations, and similar results were obtained for the maximum extent of metal removal. Heat-inactivated cells removed a maximum of 6.04 mgCd/g at 0.5 mgCd/l. The highest extent of metal removal, analyzed at various pH values, was 0.09 mgCd/g at pH 7.0. Both strains of the microalga tested have proven effective in removing a toxic heavy metal from aqueous solutions, hence supporting their choice for bioremediation strategies of industrial effluents.

Ochratoxin A removal in synthetic media by living and heat-inactivated cells of Oenococcus oeni isolated from wines

The capacity of Oenococcus oeni to eliminate ochratoxin A (OTA) from synthetic media in different conditions was studied. Ten tested O. oeni strains removed OTA from the medium but with significant differences depending on the strain, incubation period, and initial OTA level in the medium. Mycotoxin reductions higher than 60% were recorded in 14-day cultures spiked with 2 μg OTA/l. Toxin removal was independent of bacterial viability and culture medium composition. This is the first study carried out to study OTA removal dynamics by living and heat-inactivated cells of O. oeni. The results aim that this bacterium may be a very useful tool to control OTA in food and beverages.

Heterologous protective immunization elicited in mice by Pasteurella multocida fur ompH.

Different strategies have been developed to produce vaccines against Pasteurella multocida. The approach described herein involves overexpression on the bacterial cell surface of Fur-regulated IROMPs (iron-regulated outer-membrane proteins). Accordingly, the ability of fur mutants to promote heterologous protection was examined in a Swiss mouse animal model. Twofur mutants derived from P. multocida were isolated, one of which was also defective in the OmpH protein. In mice challenged with virulent P. multocida, outer-membrane protein (OMP) extracts of fur cells conferred the same protection as obtained with wild-type cells grown in iron-depleted medium. Total protection was achieved with 40 microg of OMP extract from the fur ompH mutant. Mice administered heat-inactivated fur ompH cells were 60% cross-protected. The presence of a galE mutation in these cells did not further increase the protection level. Additionally, cell disruption by sonication provoked a higher level of protection than conferred by heat-treated cells. Taken together, the results showed that P. multocida fur ompH cells offer a simple and suitable approach for cross-protecting animals against infection with P. multocida.

Decrease of phosphate concentration in the medium by Brevibacterium casei cells

Brevibacteria able to decrease phosphate concentration in the medium are of interest for the study of the role of bacteria in the phosphorus cycle and for development of biotechnology of phosphate removal from waste. Brevibacterium casei, Brevibacterium linens, and Brevibacterium epidermidis grown in media with initial phosphorus concentrations of 1-11 mM were shown to decrease its concentration by 90%. The composition of the incubation medium required for B. casei to carry out this process was established. This process occurs in the absence of glucose but requires the presence of Mg2+, NH4+, and alpha-ketoglutarate. The latter two components may be replaced by amino acids metabolized to NH4+ and alpha-ketoglutarate: histidine, arginine, glutamine, proline, or glutamic acid. No formation of insoluble phosphate salts was observed when the media were incubated under the same conditions with heat-inactivated cells or without cells at pH 7-8.5.

Impact of lactic acid bacteria on oxidative DNA damage in human derived colon cells

It is assumed that reactive oxygen species (ROS) play a key role in inflammatory bowel diseases and colon cancer and a number of studies indicate that lactic acid bacteria (LAB) possess antioxidant properties and may prevent these diseases. In the present study, we developed a model which allowed us to investigate the prevention of oxidative DNA damage in human derived colon (HT29) cells by LAB. Furthermore, we investigated if these effects correlate with superoxide ( O 2 - ) resistance of the strains. The protective properties of 55 strains were monitored in single cell gel electrophoresis (SCGE) assays. After preincubation of the cells with LAB (60 min), oxidative damage was induced by exposure to plumbagin (5.0 μM, 120 min) which releases O 2 - or by hydrogen peroxide (50 μM, 10 min); O 2 - resistance was monitored in plate growth inhibition assays. 25 strains (45%) reduced plumbagin induced DNA migration while only few of them (20%) were protective towards hydrogen peroxide induced damage. The strongest effects (up to 60% reduction of O 2 - induced DNA migration) were observed with representatives of the species Streptococcus thermophilus. The prevention of DNA damage in the colon cells by the bacteria did not correlate with their O 2 - resistance. Additional experiments indicate that the reduction of oxidative damage is only seen with viable bacteria but not with heat inactivated cells and that it takes also place when the colon cells are separated from the LAB by permeable filter membranes indicating that the bacteria release ROS protective factors into the medium. Dose response experiments showed that the protection depends on the concentration of the bacteria; significant effects were observed with titers ⩾3 × 10 6−7 cells/ml. Unexpectedly, we found that a substantial fraction of the strains (13%) induced DNA damage in untreated cells, some of them increased also the effects of the ROS generating chemicals. Preliminary experiments with tetramethylbenzidine (TMB) agar indicate that this phenomenon may be due to release of hydrogen peroxide by the bacteria. Overall, our study shows that the impact of LAB on DNA damage in human derived colon cells is ambivalent; while the majority of strains was protective against oxidative damage some of them induced per se pronounced DNA migration. Since the effects were seen with bacterial concentrations which may be reached in the intestinal tract after consumption of fermented milk products, it is likely that the effects we observed in the present study are relevant for humans.

TWO SINGLE-NUCLEOTIDE POLYMORPHISMS IN THE 5???-UNTRANSLATED REGION OF THE HBD-1 GENE ARE ASSOCIATED WITH THE SUSCEPTIBILITY TO SEVERE SEPSIS

Severe sepsis is an infection-initiated, inflammatory syndrome which complicated with organ dysfunction. Genetic factors affect the incidence and outcome of severe sepsis. Human beta-defensins, cysteine-rich cationic antimicrobial polypeptides with 3 disulfide bridges, play an important role in innate immunity and adaptive immunity in sepsis. Our previous studies have shown that human beta-defensin 1 gene was transiently transcribed following the induction of LPS or heat-inactivated bacterial cells and the inducible expression of beta-defensin1 gene showed interindividual variability. The purpose of this study was to evaluate whether single-nucleotide polymorphisms (SNP) in the 5′-untranslated region of the HBD-1 gene are associated with the susceptibility to severe sepsis or with the outcome of severe sepsis. Two hundred and fifty patients with severe sepsis who had been treated at the intensive care unit of the university hospital were studied. One hundred seventy postoperative patients without sepsis served as controls. The DNA fragment containing the three SNPs (-52G/A, -44C/G and -20G/A) in the 5′-untranslated region of the HBD-1 gene were amplified and sequenced. There was a significant difference in the distribution of genotype and alleles of -20G/A SNP and -44C/G SNP between severe sepsis and controls. While, there was no significant difference in the distribution of genotype and alleles of -52G/A SNP between severe sepsis and controls. Further, there was no significant difference in the distribution of genotype and alleles of -20G/A SNP, -44C/G and -52G/A SNP between survivors and non-survivors. -20G/A SNP and -44C/G SNP is associated with the susceptibility to severe sepsis.

A functional dlt operon, encoding proteins required for incorporation of d-alanine in teichoic acids in gram-positive bacteria, confers resistance to cationic antimicrobial peptides in Streptococcus pneumoniae.

Streptococcus pneumoniae is one of the few species within the group of low-G +C gram-positive bacteria reported to contain no d-alanine in teichoic acids, although the dltABCD operon encoding proteins responsible for d-alanylation is present in the genomes of two S. pneumoniae strains, the laboratory strain R6 and the clinical isolate TIGR4. The annotation of dltA in R6 predicts a protein, d-alanine-d-alanyl carrier protein ligase (Dcl), that is shorter at the amino terminus than all other Dcl proteins. Translation of dltA could also start upstream of the annotated TTG start codon at a GTG, resulting in the premature termination of dltA translation at a stop codon. Applying a novel integrative translation probe plasmid with Escherichia coli 'lacZ as a reporter, we could demonstrate that dltA translation starts at the upstream GTG. Consequently, S. pneumoniae R6 is a dltA mutant, whereas S. pneumoniae D39, the parental strain of R6, and Rx, another derivative of D39, contained intact dltA genes. Repair of the stop codon in dltA of R6 and insertional inactivation of dltA in D39 and Rx yielded pairs of dltA-deficient and dltA-proficient strains. Subsequent phenotypic analysis showed that dltA inactivation resulted in enhanced sensitivity to the cationic antimicrobial peptides nisin and gallidermin, a phenotype fully consistent with those of dltA mutants of other gram-positive bacteria. In addition, mild alkaline hydrolysis of heat-inactivated whole cells released d-alanine from dltA-proficient strains, but not from dltA mutants. The results of our study suggest that, as in many other low-G+C gram-positive bacteria, teichoic acids of S. pneumoniae contain d-alanine residues in order to protect this human pathogen against the actions of cationic antimicrobial peptides.

Efficacy of injection vaccines against Flavobacterium psychrophilum in rainbow trout, Oncorhynchus mykiss (Walbaum)

Efficacy of mineral oil-based experimental injection vaccines against Flavobacterium psychrophilum were tested in rainbow trout, Oncorhynchus mykiss (Walbaum), under laboratory and field conditions. The vaccines consisted of formalin- or heat-inactivated whole bacterium cell preparations of two different serotypes (Fd and Th) or a combination of serologically different F. psychrophilum (Fd and/or Th and/or Fp(T);Th). Specific antibody responses against the bacterium in plasma and skin mucus were evaluated post-vaccination with enzyme-linked immunosorbent assay. Efficacy of the vaccinations was determined by challenge trials to F. psychrophilum with the vaccinated rainbow trout. Significantly higher antibody levels in plasma were detected in vaccinated fish compared with mock-vaccinated fish. Injection vaccination did not trigger specific antibody production in the skin mucus. Significantly higher survival of i.p. vaccinated fish compared with non-vaccinated fish was observed during the challenge. The results suggest that mineral oil-based injectable vaccines containing formalin- or heat-inactivated virulent cells of F. psychrophilum effectively triggered specific antibody production and protected the fish against bacterial cold water disease.

Demonstration of Aminopeptidase Activities Secreted byAmsonia tabernaemontana Walt. Cells

Using synthetic substrates, an uncomplicated and sensitive procedure for the determination of extracellular aminopeptidase was developed. The studied enzyme produced by the tested plant material (calli, cell suspension culture and roots of Amsonia tabernaemontana Walt. seedlings) hydrolyzed the substrates β-naphthylamides (βNA) and 4-(phenylazo) phenylamides (PAP-amide) of the amino acids to β-naphthylamine and 4-(phenylazo) aniline, respectively, and amino acid. The β-naphthylamides of the amino acids were applied for the identification of extracellular aminopeptidase, whereas the 4-(phenylazo) phenylamides of the amino acids were used for the determination of intra- and extracellular aminopeptidase activity. By simultaneous azocoupling of β-naphthol with Fast Garnet GBC salt on agar plates a corresponding brown-red hardly water-soluble azo-dye was produced. The evaluation of dyed zones allowed the extracellular aminopeptidase activity to be assessed. No coloration of the agar medium was observed without inoculum, with heat-inactivated cells (10 min at 100 °C) or in medium inoculated without substrate. On the agar plates with substrate and sterile Amsonia seedlings, changes in coloration were observed indicating a release of aminopeptidase from the roots during germination. The results show a 91.0 % intracellular and 9.0 % extracellular distribution of aminopeptidase activity, when a cell suspension culture of A. tabernaemontana Walt. as the plant material was used. The agar plate method described permits the rapid, uncomplicated and specific detection of plant producers of extracellular aminopeptidase, which could be particularly useful in future inhibitory and/or biotechnological studies.

Detection of Kluyveromyces marxianus and other spoilage yeasts in yoghurt using a PCR-culture technique

A combined PCR-culture technique was developed for the detection of viable yeasts in yoghurt samples. Yoghurt samples were inoculated with either viable or heat-inactivated Kluyveromyces marxianus cells, and analyzed before and after incubation for 24 h at 25 °C under agitation. DNA was extracted from the samples and amplified using yeast-specific primers targeted at the gene coding for the 18S rRNA. A 251-bp fragment was amplified by the Polymerase Chain Reaction from the yoghurt samples containing initial yeasts counts of 10 cfu g − 1 or higher, whereas no PCR product was generated from control uninoculated yoghurt samples. Comparison of PCR results obtained before and after the incubation step was used to assess yeast viability. Viability was also confirmed by plating on Sabouraud–Dextrose–Chloramphenicol Agar. Moreover, comparison of the results obtained using PCR-culture and plate count methods for the analysis of commercial yoghurt samples, demonstrated that the PCR-culture technique developed in this work can be very useful for the rapid detection of viable spoilage yeasts in dairy industries.

Ferrihydrite reduction by Geobacter species is stimulated by secondary bacteria.

Geobacter species such as G. bremensis, G. pelophilus, and G. sulfurreducens are obligately anaerobic and grow in anoxic, non-reduced medium by fast reduction of soluble ferric citrate. In contrast, insoluble ferrihydrite was either only slowly or not reduced when supplied as electron acceptor in similar growth experiments. Ferrihydrite reduction was stimulated by addition of a reducing agent or by concomitant growth of secondary bacteria that were physiologically and phylogenetically as diverse as Escherichia coli, Lactococcus lactis, or Pseudomonas stutzeri. In control experiments with heat-inactivated Geobacter cells and viable secondary bacteria, no ( E. coli, P. stutzeri) or only little ( L. lactis) ferrihydrite was reduced. Redox indicator dyes showed that growing E. coli, P. stutzeri, or L. lactis cells lowered the redox potential of the medium in a similar way as a reducing agent did. The lowered redox potential was presumably the key factor that stimulated ferrihydrite reduction by all three Geobacter species. The observed differences in anoxic non-reduced medium with ferric citrate versus ferrihydrite as electron acceptor indicated that reduction of these electron acceptors involved different cellular components or different biochemical strategies. Furthermore, it appears that redox-sensitive components are involved, and/or that gene expression of components needed for ferrihydrite reduction is controlled by the redox state.

Study of Extracellular Plant Lactase

Using a synthetic substrate, a simple and sensitive procedure for the determination of extracellular lactase was developed. The enzyme studied produced by the tested plant material hydrolyzed the substrate (1‐naphtyl‐α‐D‐galactopyranoside) to α‐D‐galactose and 1‐naphthol. By simultaneous azocoupling of 1‐naphthol hardly water‐soluble azo‐dyes were produced. The evaluation of the intensity of dyed zones allowed the extracellular lactase activity to be assessed. The agar plate method described permitted rapid, simple, and specific detection of plant producers of extracellular lactase and proved to be perspectively useful in inhibitory and/or biotechnological studies.

Activation of NF-kappaB in intestinal epithelial cells by E. coli strains isolated from the colonic mucosa of IBD patients.

The involvement of bacteria in the pathogenesis of inflammatory bowel disease has been discussed for several years. In this study we evaluated the ability of E. coli isolates from inflamed and noninflamed colonic mucosa to activate NF-kappaB. Fifteen bacterial strains from inflamed and six from noninflamed colonic tissues from IBD patients. Their ability to induce NF-kappaB activation was examined in vitro by gel-shift assays. The activation of the TNF-alpha promoter was determined by reporter gene assays. Bacterial isolates were characterized by invasion assays, electron microscopy, and PCR. Four of 15 E. coli bacterial isolates from inflamed IBD tissues induced NF-kappaB activity in intestinal epithelial cells as determined by gel-shift assays. NF-kappaB activation was only seen with living bacteria but not with heat-inactivated cells. Isolates from noninflamed tissues and a wild-type E. coli control strain induced a weaker or no activation. Reporter gene assays with a construct comprising a luciferase gene driven by the TNF-alpha promoter revealed that isolates from Crohn's disease patients induced a stronger activation of the TNF-alpha gene than isolates from ulcerative colitis patients. The isolated bacteria invaded HT-29 cells, although typical virulence genes for enteropathogenic, enterhemorrhagic, or enteroinvasive E. coli, i.e., eae, tir, EspA, Per (A-C), ipaC, were not detected in these cells. Bacterial invasion was additionally confirmed by electron microscopy examination. Our results indicate that E. coli strains can be found in the mucosa of some IBD patients which are able to activate NF-kappaB similar to known pathogenic strains. The absence of several virulence genes in these cells suggests that they are members of the luminal flora which acquire as yet unidentified virulence determinants and are therefore involved in the pathophysiology of IBD.

Calculating Microbial Survival Parameters and Predicting Survival Curves from Non-Isothermal Inactivation Data

Irrespective of whether the isothermal semi-logarithmic survival curves of heat inactivated microbial cells or spores are linear or nonlinear, it is theoretically possible to numerically calculate their survival parameters from inactivation data obtained under non-isothermal conditions. A method to do the calculation, when the temperature history (‘profile’) is expressed algebraically, is demonstrated with simulated survival curves. It has been tested with the published survival data of Salmonella, whose nonlinear semi-logarithmic isothermal survival curves can be described by a power law model. The reported survival ratios of Salmonella, determined during non-isothermal heat treatments in a broth and in ground chicken breast, were used to estimate its isothermal survival parameters in the two media and their temperature dependence. These, in turn, were used to predict the cells' survival curves under different temperature ‘profiles.’ There was a good agreement between the predicted and the reported experimental survival curves in the broth case and reasonable agreement in the ground chicken breasts, where the database was considerably smaller. The development of a mathematical method to calculate survival parameters from non-isothermal inactivation data will eliminate the need to determine these parameters under isothermal conditions, which can only be approximated and are technically difficult to perform. In many cases, the proposed method will also enable the determination of the survival parameters in the actual food or medium of interest, which may contain particles, or is too viscous to be heated and cooled effectively using the currently available experimental procedures. In principle, the described mathematical method can also be used to assess organisms' survival parameters in nonthermal inactivation processes, such as exposure to a dissipating chemical agent or the application of ultra high-pressure.