Concentration Of Sorbic Acid Research Articles

Survival of the functional yeast Kluyveromyces marxianus B0399 in fermented milk with added sorbic acid

In this study, the survival of the functional yeast Kluyveromyces marxianus B0399 in an industrially produced fermented milk was evaluated. In particular, the yeast viability was assessed throughout the entire shelf-life of the product (30 d) to ensure the presence of the effective yeast dose (20 million viable cells for each serving of 125g) while avoiding, by sorbic acid addition, yeast growth, which could affect product quality and stability. To find the best combination of yeast and sorbic acid concentration, 13 different combinations were tested, and then 2 of them were chosen for industrial production. In production at lower concentrations (30 million viable cells, 150mg/kg of sorbic acid) the effective dose was maintained only at 4 and 6°C, whereas at higher dosages (70 million viable cells, 250mg/kg of sorbic acid) the effect of temperature was less evident. In all the trials, the concentration of sorbic acid was not affected by microbial metabolism and remained stable throughout the entire shelf-life.

Application of biodegradable films made from rice flour, poly(butylene adipate-co-terphthalate), glycerol and potassium sorbate in the preservation of fresh food pastas

The objective of this study was to evaluate the shelf life of fresh lasagna pasta intercalated with extruded films made from blends of rice flour, poly(butylene adipate-co-terphthalate) (PBAT), glycerol and potassium sorbate, and quantify the concentration of sorbic acid that migrated from the films into the product. The microbiological analyses carried out at zero time showed the product to be within the standards established by Brazilian legislation, and the microbial count was lower in the food pastas containing sorbic acid that had migrated from the films. The presence of slime on the surface of the food pastas was one of the determinant factors in their shelf life. The addition of 3 g 100 g−1 potassium sorbate to the biodegradable films made of rice flour, PBAT and glycerol was recommended for application to fresh lasagna pasta, since this concentration was sufficient to extend the shelf life while maintaining a lower sorbic acid concentration in the final product.

Effects of different sorbic acid and moisture levels on chemical and microbial qualities of sun-dried apricots during storage

Effects of different sorbic acid (SA) (0, 488–530 and 982–1087mg/kg) and moisture [intermediate (271–278g/kg) and high (341–344g/kg)] levels on the chemical and microbiological qualities of sun-dried apricots during storage at different temperatures (4, 10, 20 and 30°C) for 10months were evaluated. Moisture content and SA concentration showed significant effect on brown colour formation, β-carotene oxidation and microbial load (p<0.05). As moisture content increased, brown colour formation decreased. Moreover, SA oxidation protected β-carotene from oxidation. Although no microbial spoilage was observed in the samples with intermediate moisture content, control group with high moisture was spoiled by yeast and mould in 1–3months of storage at all temperatures studied; 488mgSA/kg was sufficient to prevent the spoilage. Regardless of moisture content, 500mgSA/kg was found to be effective for the prevention of brown colour formation and inhibition of microbial growth.

Identification and characterisation of organisms associated with chocolate pralines and sugar syrups used for their production

Spoilage of chocolate pralines, due to growth of microorganisms tolerating low water activity, causes problems in the confectionary industry. Therefore, an increased knowledge on which organisms are present in the chocolate fillings and their tolerance towards low aw, pH, ethanol and other preservatives is needed.Using media containing 40–50% glucose (aw 0.872–0.925) bacteria, yeasts and moulds were isolated from chocolate pralines (aw 0.70–0.898) of nine manufactures and sugar syrups (aw 0.854) used as ingredient in chocolate praline production by one of the manufacturers. Isolates were identified by conventional microbiological analyses and by sequencing of their 16S rRNA, 26S rRNA (D1/D2-region) or calmodulin genes. Further, for several species the identity was confirmed by amplification and sequencing of additional genes.In total 677 isolates were identified as belonging to ten different bacteria species, six yeast species and ten mould species with yeast being the most frequently isolated. Bacteria and moulds were found in low numbers, whereas yeast were found in numbers up to 107CFU/g. The most frequently isolated yeast, bacteria and moulds belonged to the species of Zygosaccharomyces rouxii, Bacillus subtilis and Aspergillus terreus, respectively.Fifteen isolates were screened for their ability to grow in presence of low aw (0.65–0.90), low pH (pH=2.0–7.0), ethanol (0–15%), sorbic acid (0–1500ppm) and different temperatures (15°C–25°C) relevant for chocolate manufacturing. Z. rouxii was overall the most tolerant organism to the stress factors and grew within the same range of environmental conditions as found in chocolate pralines. It was able to grow at water activities down to 0.70, ethanol concentrations up to 6.0%, pH down to pH2.0, sorbic acid concentrations up to 1500ppm and at all temperatures tested. Eurotium amstelodami also showed high tolerance towards all the stress factors except for ethanol. None of the bacteria were able to grow at the conditions tested. However, B. subtilis survived the 60day incubation period.

Schizosaccharomyces isolation method

This study discusses the optimization of a selective and differential medium which would facilitate the isolation of Schizosaccharomyces (a genus with a low incidence compared to other microorganisms) to select individuals from this genus for industrial purposes, especially in light of the recent recommendation of the use of yeasts from this genus in the wine industry by the International Organisation of Vine and Wine, or to detect the presence of such yeasts, for those many authors who consider them food spoilers. To this end, we studied various selective differential agents based on the main physiological characteristics of these species, such as their high resistances to high concentrations of sugar, sulfur dioxide, sorbic acid, benzoic acid, acetic acid or malo ethanolic fermentation. This selective medium is based on the genus resistance to the antibiotic actidione and its high resistance to inhibitory agents such as benzoic acid. Malic acid was used as a differential factor due to the ability of this genus to metabolise it to ethanol, which allows detecting of the degradation of this compound. Lastly, the medium was successfully used to isolate strains of Schizosaccharomyces pombe from honey and honeycombs.

English

This study discusses the optimisation of a selective and differential medium which would facilitate the isolation of&nbsp;Schizosaccharomyces&nbsp;(a genus with a low incidence compared to other microorganisms) to select individuals from this genus for industrial purposes, especially in light of the recent approval of the use of yeasts from this genus in the wine industry by the International Organisation of Vine and Wine, or to detect the presence of such yeasts, for those many authors who consider them food spoilers. To this end, we studied various selective-differential agents based on the main the physiological characteristics of this species, such as its high resistance to high concentrations of sugar, sulfur dioxide, sorbic acid, benzoic acid, acetic acid or malo-ethanolic fermentation. This selective medium is based on the resistance of the genus to the antibiotic actidione and its high resistance to inhibitory agents such as benzoic acid compared to possible microorganisms which can give rise to false-positive results. Malic acid was used as a differential factor due to the ability of this genus to metabolise it to ethanol, which allows detecting of the degradation of this compound. Lastly, the medium was successfully used to isolate strains of&nbsp;Schizosaccharomyces pombe&nbsp;from honey. &nbsp; Key words:&nbsp;Schizosaccharomyces pombe, benzoic acid, actidione, differential selective medium, malic acid.

"Effect of sorbic acid on the storage quality of Kaladhi-an acid coagulated milk product".

The present study was conducted to determine the effect of three different levels of sorbic acid (0.1%, 0.2% and 0.3%) on the shelf life and storage quality of Kaladhi. Kaladhi was prepared from pasteurized buffalo milk standardized to 6% fat and 9% SNF with coagulation at 40°C using 5% lactic acid as a coagulant. Kaladhi prepared without sorbic acid served as control and was compared with the products treated with different levels of sorbic acid for a storage period of 35days at ambient temperature. The results showed a significant (P < 0.05) effect of sorbic acid on most of the physicochemical parameters i.e. titratable acidity, free fatty acid content (% oleic acid) and thiobarbituric acid value which showed a decreasing trend with increasing concentration of sorbic acid. However, a non-significant (P > 0.05) effect of sorbic acid was observed on pH and proximate parameters of the product. Kaladhi treated with 0.3% sorbic acid retained most desirable physicochemical and sensory properties throughout the storage period hence, was considered the best.

The Effects of Koji and Histidine on the Formation of Histamine in Anchovy Sauce and the Growth Inhibition of Histamine Degrading Bacteria with Preservatives

Koji and histidine have been applied to accelerate the fermentation of fish sauce for the purpose of shortening the manufacturing period and cost. The histamine contents of anchovy sauces fermented at 15 and 25 °C for 12 months were 3.7-3.8 mg/mL. The histamine content increased up to 6 months of ripening and then decreased, where at 25 °C was higher than at 15 °C at 6 months of ripening, but similar at 12 months. Koji decreased the histamine formation at 3 months at 15 °C, but no significant difference at 12 months, whereas histidine increased at 6 months at 15 °C, but no great difference at 25 °C. Histamine degrading bacteria isolated from the anchovy was identified to Staphylococcus xylosus. Optimal pH for the growth of S. xylosus was neutral. The growth of S. xylosus was strongly inhibited as the concentration of NaCl, benzoic acid, and sorbic acid increased.

Weak-acid preservatives: pH and proton movements in the yeast Saccharomyces cerevisiae

Weak-acid preservatives commonly used to prevent fungal spoilage of low pH foods include sorbic and acetic acids. The “classical weak-acid theory” proposes that weak acids inhibit spoilage organisms by diffusion of undissociated acids through the membrane, dissociation within the cell to protons and anions, and consequent acidification of the cytoplasm. Results from 25 strains of Saccharomyces cerevisiae confirmed inhibition by acetic acid at a molar concentration 42 times higher than sorbic acid, in contradiction of the weak-acid theory where all acids of equal pKa should inhibit at equimolar concentrations. Flow cytometry showed that the intracellular pH fell to pH4.7 at the growth-inhibitory concentration of acetic acid, whereas at the inhibitory concentration of sorbic acid, the pH only fell to pH6.3. The plasma membrane H+-ATPase proton pump (Pma1p) was strongly inhibited by sorbic acid at the growth-inhibitory concentration, but was stimulated by acetic acid. The H+-ATPase was also inhibited by lower sorbic acid concentrations, but later showed recovery and elevated activity if the sorbic acid was removed. Levels of PMA1 transcripts increased briefly following sorbic acid addition, but soon returned to normal levels. It was concluded that acetic acid inhibition of S. cerevisiae was due to intracellular acidification, in accord with the “classical weak-acid theory”. Sorbic acid, however, appeared to be a membrane-active antimicrobial compound, with the plasma membrane H+-ATPase proton pump being a primary target of inhibition. Understanding the mechanism of action of sorbic acid will hopefully lead to improved methods of food preservation.

Effect of sorbic acid and some other food preservatives on human serum cholinesterase activity

The effect of some selected food preservatives on serum cholinesterase was determined. It was found that potassium metabisulphite, methyl parabene and propyl parabene caused a significant increase while sacharine, benzoic acid, salicylic acid, copper carbonate and sorbic acid caused a significant decrease in cholinesterase activity. The behavior of serum cholinesterase activity in response to a gradual change in the incubation time as well as the sorbic acid concentration was also studied. The graphical and statistical analysis of the data showed an exponential decrease in cholinesterase activity with an increase in the concentration of sorbic acid. The cholinesterase activity was also found to be decreased exponentially with an increase in the incubation time. The regression analysis showed a good agreement between the experimental and calculated values. Keywords: Sorbic acid, enzyme activity, cholinesterase, inhibition sensitivity

Controlled release of sorbic acid from bacterial cellulose based mono and multilayer antimicrobial films

Biodegradable bacterial cellulose (BC) based films, incorporating sorbic acid (SA) as antimicrobial agent, have been obtained. Monolayer films, prepared using powdered BC (BCP) and poly(vinyl) alcohol (PVA), were coated with BC membrane to obtain multilayer films. Tests indicated that both SA and BCP concentration influenced sensitivity to water, release rate and antimicrobial ability of mono and multilayer films. Swelling degree, water vapour permeability and water solubility increased with SA content, but decreased with BCP addition. However in case of multilayer films, water solubility was negligible. Colour measurements indicated no degradation of SA during film preparation. The release of SA was faster when BCP concentration was higher but significantly slower, as a consequence of formed crystals dissolution, when antimicrobial concentration was increased. Furthermore, compared to the results for the monolayer films, an important decrease of SA release rate through the multilayer films was determined. The antimicrobial effect was tested against Escherichia coli K12-MG1655. The results obtained indicated that the new biocomposite films could be promising antimicrobial food packaging materials.

Effect of naturally occurring antimicrobials and chemical preservatives on the growth of Aspergillus Parasiticus.

Effect of water activity (aw, 0.99), pH (4.5) and their interaction on the growth inhibition of Aspergillus parasiticus was studied on potato dextrose agar (PDA) using various antimicrobial agents (citral, carvacrol, eugenol, cineole, thymol guaiacol, vanillin, anethol, potassium sorbate and sorbic acid). The results demonstrate that colony diameter (mm) exhibited a constant increase with time (zero order kinetics) for all antimicrobials evaluated. Eugenol and sorbic acid inhibited the test fungi at 300 and 600ppm, respectively. Radial growth rate (RGR) of A. parasiticus was significantly (p < 0.05) different among different antimicrobials as well as the concentrations tested. However, this difference was not observed with higher concentration of citral, eugenol, vanillin and sorbic acid. Among the antimicrobials evaluated potassium sorbate, cineole, anethol and guaiacol were least effective. Thymol, eugenol and carvacrol were more effective in inhibiting A. parasiticus even with low concentration (150ppm) as their mean RGR was zero even after 20days of incubation (pH 4.5).

Characteristics and distribution of low molecular weight organic acids in the sediment porewaters in Bosten Lake, China

The composition and vertical profiles of low molecular-weight organic acids (LMWOAs) and the contribution of them to dissolved organic matter (DOM) in sediment porewaters in Bosten Lake, Xinjiang, China were investigated. The results showed that total concentration of LMWOAs was up to 94.5 μmol/L and their proportion in DOM was 5.6%, suggesting that LMWOAs were important chemical components in DOM in lake sediment porewaters. Among the seven LMWOAs, pyruvic and acetic acid had the highest concentrations with 26.30 and 8.31 μmol/L, accounting for 51.4% and 14.92% of LMWOAs, respectively. Trifluoroacetic and sorbic acid had the lowest concentrations, indicating that the compositions of LMWOAs in relative reducing environments were largely different from those reported in glacier, atmosphere and soils. The concentrations of lactic, acetic, formic, sorbic and oxalic acid decreased with increasing depth, probably relating to stronger microbial activities in the initial stage of early diagenesis. Trifluoroacetic acid was mainly anthropogenic with its concentration, showing a diffusive trend from the surface to bottom sediments. The concentrations of lactic acid and nitrate generally showed a consistent profile. The increasing concentration of pyruvic acid in the vertical profile was just opposite to that of sulfate, revealing a significant negative relationship between them. Oxalic acid remained constant except for an obvious peak at 6 cm depth. The results indicated the diversities in sources and behaviors for various LMWOAs during early diagenesis in sediments.

Evaluation of urinary biomarkers of exposure to benzene: correlation with blood benzene and influence of confounding factors

trans,trans-Muconic acid (t,t-MA) is generally considered as a useful biomarker of exposure to benzene. However, because of its lack of specificity, concerns about its value at low level of exposure have recently been raised. The aim of this study was (a) to compare t,t-MA, S-phenylmercapturic acid (SPMA) and benzene (B-U) as urinary biomarkers of exposure to low levels of benzene in petrochemical workers and, (b) to evaluate the influence of sorbic acid (SA) and genetic polymorphisms of biotransformation enzymes on the excretion of these biomarkers. A total of 110 workers (including 24 smokers; 2-10 cigarettes/day) accepted to take part in the study. To assess external exposure to benzene, air samples were collected during the whole working period by a passive sampling device attached close to the breathing zone of 98 workers. Benzene was measured in blood (B-B) samples taken at the end of the shift, and was considered as the reference marker of internal dose. Urine was collected at the end of the shift for the determination of B-U, SPMA, t,t-MA, SA and creatinine (cr). B-U and B-B were determined by head-space/GC-MS, SPMA and SA by LC-MS, t,t-MA by HPLC-UV. Most (89%) personal measurements of airborne benzene were below the limit of detection (0.1 ppm); B-B ranged from <0.10 to 13.58 mug/l (median 0.405 microg/l). The median (range) concentrations of the urinary biomarkers were as follows: B-U 0.27 microg/l (<0.10-5.35), t,t-MA 0.060 mg/l (<0.02-0.92), SPMA 1.40 microg/l (0.20-14.70). Urinary SA concentrations ranged between <3 and 2,211 microg/l (median 28.00). Benzene concentration in blood and in urine as well as SPMA, but not t,t-MA, were significantly higher in smokers than in non-smokers. The best correlation between B-B and urinary biomarkers of exposure were obtained with benzene in urine (microg/l r = 0.514, P < 0.001; microg/g cr r = 0.478, P < 0.001) and SPMA (microg/l r = 0.495, P < 0.001; microg/g cr r = 0.426, P < 0.001) followed by t,t-MA (mg/l r = 0.363, P < 0.001; mg/g cr r = 0.300, P = 0.002). SA and t,t-MA were highly correlated (r = 0.618, P < 0.001; corrected for cr r = 0.637). Multiple linear regression showed that the variation of t,t-MA was mostly explained by SA concentration in urine (30% of the explained variance) and by B-B (12%). Variations of SPMA and B-U were explained for 18 and 29%, respectively, by B-B. About 30% of the variance of B-U and SPMA were explained by B-B and smoking status. Genetic polymorphisms for biotransformation enzymes (CYP2E1, EPHX1, GSTM1, GSTT1, GSTP1) did not significantly influence the urinary concentration of any of the three urinary biomarkers at this low level of exposure. At low levels of benzene exposure (<0.1 ppm), (1) t,t-MA is definitely not a reliable biomarker of benzene exposure because of the clear influence of SA originating from food, (2) SPMA and B-U reflect the internal dose with almost similar accuracies, (3) genetically based inter-individual variability in urinary excretion of biomarkers seems negligible. It remains to assess which biomarker is the best predictor of health effects.

Physiological state of single cells of Listeria innocua in organic acids

The growth of Listeria innocua in three organic acids was monitored by optical density measurements in a Bioscreen C automatic plate reader (Labsystems, Finland). The method described by Metris et al. [Metris, A., George, S.M., Baranyi, J., 2006. Use of optical density detection times to assess the effect of acetic acid on single-cell kinetics. Applied and Environmental Microbiology 72, 6674–6679.], was used to estimate both the growth rate and the lag time of single cells. It was found that the logarithm of both the growth rates and the population lag times increased linearly with sorbic acid concentration in the same way as previously described with acetic acid but the relationship was not linear with lactic acid. Of the three acids tested, sorbic was the most inhibitory for an equivalent undissociated acid concentration. The effect of lactic acid was dependent on both the growth phase of the inoculum and the inoculum concentration.

Performance of a Growth–No Growth Model for Listeria monocytogenes Developed for Mayonnaise-Based Salads: Influence of Strain Variability, Food Matrix, Inoculation Level, and Presence of Sorbic and Benzoic Acid

A previously developed growth–no growth model for Listeria monocytogenes, based on nutrient broth data and describing the influence of water activity (aw), pH, and acetic acid concentrations, was validated (i) for a variety of L. monocytogenes strains and (ii) in a laboratory-made, mayonnaise-based surimi salad (as an example of a mayonnaise-based salad). In these challenge tests, the influence of the inoculation level was tested as well. Also, the influence of chemical preservatives on the growth probability of L. monocytogenes in mayonnaise-based salads was determined. To evaluate the growth–no growth model performance on the validation data, four quantitative criteria are determined: concordance index, % correct predictions, % fail-dangerous, and % fail-safe. First, the growth probability of 11 L. monocytogenes strains, not used for model development, was assessed in nutrient broth under conditions within the interpolation region. Experimental results were compared with model predictions. Second, the growth–no growth model was assessed in a laboratory-made, sterile, mayonnaise-based surimi salad to identify a possible model completeness error related to the food matrix, making use of the above-mentioned validation criteria. Finally, the effect on L. monocytogenes of common chemical preservatives (sorbic and benzoic acid) at different concentrations under conditions typical of mayonnaise-based salads was determined. The study showed that the growth–no growth zone was properly predicted and consistent for all L. monocytogenes strains. A larger prediction error was observed under conditions within the transition zone between growth–no growth. However, in all cases, the classification between no growth (P = 0) and any growth (P > 0) occurred properly, which is most important for the food industry, where outgrowth needs to be prevented in all instances. The results in the sterile mayonnaise-based salad showed again that the growth–no growth zone was well predicted but that also, in real food systems, a transition zone between growth and no growth exists. This became even more obvious for lower inoculation levels. The maximum-allowed concentration of benzoic and sorbic acid in mayonnaise-based salads, according to the European Union legislation, eliminated the growth of L. monocytogenes. Concentrations of 600 and 300 ppm were already sufficient to inhibit growth at 7 and 4°C, respectively, under conditions associated with mayonnaise-based salads (pH 5.6; aw, 0.985).

Decarboxylation of Sorbic Acid by Spoilage Yeasts Is Associated with the PAD1 Gene

The spoilage yeast Saccharomyces cerevisiae degraded the food preservative sorbic acid (2,4-hexadienoic acid) to a volatile hydrocarbon, identified by gas chromatography mass spectrometry as 1,3-pentadiene. The gene responsible was identified as PAD1, previously associated with the decarboxylation of the aromatic carboxylic acids cinnamic acid, ferulic acid, and coumaric acid to styrene, 4-vinylguaiacol, and 4-vinylphenol, respectively. The loss of PAD1 resulted in the simultaneous loss of decarboxylation activity against both sorbic and cinnamic acids. Pad1p is therefore an unusual decarboxylase capable of accepting both aromatic and aliphatic carboxylic acids as substrates. All members of the Saccharomyces genus (sensu stricto) were found to decarboxylate both sorbic and cinnamic acids. PAD1 homologues and decarboxylation activity were found also in Candida albicans, Candida dubliniensis, Debaryomyces hansenii, and Pichia anomala. The decarboxylation of sorbic acid was assessed as a possible mechanism of resistance in spoilage yeasts. The decarboxylation of either sorbic or cinnamic acid was not detected for Zygosaccharomyces, Kazachstania (Saccharomyces sensu lato), Zygotorulaspora, or Torulaspora, the genera containing the most notorious spoilage yeasts. Scatter plots showed no correlation between the extent of sorbic acid decarboxylation and resistance to sorbic acid in spoilage yeasts. Inhibitory concentrations of sorbic acid were almost identical for S. cerevisiae wild-type and Deltapad1 strains. We concluded that Pad1p-mediated sorbic acid decarboxylation did not constitute a significant mechanism of resistance to weak-acid preservatives by spoilage yeasts, even if the decarboxylation contributed to spoilage through the generation of unpleasant odors.

Simultaneous determination of sorbic and benzoic acids in commercial juices using the PLS-2 multivariate calibration method and validation by high performance liquid chromatography

A new method to determine a mixture for preserving sorbic and benzoic acids in commercial juices is proposed. The PLS-2 model was obtained preparing 40 standard solutions adding concentration of sorbic and benzoic acid to filtered natural juices of apple, lemon, orange and grapefruit. The concentration of analytes in the commercial samples was evaluated using the obtained model by UV spectral data. The PLS-2 method was validated by high performance liquid chromatography (HPLC), finding a relative error less than 12% between the PLS-2 and HPLC methods in all cases.

Modelling of the growth–no growth interface of Issatchenkia occidentalis, an olive spoiling yeast, as a function of the culture media, NaCl, citric and sorbic acid concentrations: Study of its inactivation in the no growth region

A global logistic model incorporating a dummy variable for the growth medium (laboratory media or table olives brine) was used for the estimation of the growth–no growth interface of Issatchenkia occidentalis as a function of NaCl, citric and sorbic acid concentrations. The model permitted the deduction of the region where the combination of citric and sorbic acids in laboratory media (above 0.3% and 0.03% wt/vol, respectively) and brine (above 0.1% and 0.03% wt/vol), at 5% NaCl, inhibited the growth of the yeast. Subsequently, the model was validated in laboratory media within the no growth region by a response surface D-optimal design. Inactivation concentrations of sorbic acid produced a progressive loss of viability in I. occidentalis that followed a first order kinetic or downward concave inactivation curves, depending on environmental variables. These curves were properly described by a (primary) model deduced from the Weibull distribution, whose parameters, first decimal reduction time ( D β ) and shape ( β), were expressed as a function of sorbic acid concentrations (secondary model). At 5% NaCl and within the experimental region checked, an increase of 0.010% and 0.008% sorbic acid reduced D β in 10 h and decrease β by 10%. Finally, the model was also validated in real “seasoned” table olives packing reporting a complete inactivation of the yeasts' population.

Characteristics of Bacillus cereus isolates from legume-based Indian fermented foods

An antibiogram of 48 strains of Bacillus cereus isolated from 6 different kinds of legume-based Indian fermented foods (amriti, dhokla, dosa, idli, papad and wadi) was generated against 18 different antibiotics that are commonly used against foodborne diseases, mainly gastroenteritis. Each of the isolates was found to be resistant against at least nine different antibiotics. Production of extracellular enzymes, namely protease, lipase and amylase by 33%, 27% and 46%, respectively, of the isolates indicates their potentiality for food spoilage. In brain–heart infusion broth supplemented with glucose, the D 100 °C -values for the tested 12 strains ranged from 3.0 to 9.2 min. In nutrient broth, the minimum and maximum pHs permitting growth of B. cereus were 5.3 and 11.6, respectively. The minimum inhibitory concentrations of sodium chloride, benzoic acid and sorbic acid for the growth of the isolates were 65–85 mg ml −1, 400–700 μg ml −1 (pH 5.0–4.2) and 500–600 μg ml −1 (pH 5.0–4.8), respectively. Of the tested 10 strains, eight were resistant to 300 μg nisin ml −1 (pH 5.0). While studying the combined effect of selected hurdles on the growth of an isolate, the judicious combination considered was 20 mg sodium chloride, 300 μg benzoic acid and 25 μg nisin ml −1 at pH 5.6. The whole-cell protein fingerprinting (WCPF) analysis using SDS–PAGE revealed a high level of diversity among the isolates. At ⩾60% similarity level, the WCPF profiles could be grouped into four major clusters which were divided into 34 subclusters. Most of the subclusters were source-wise homogeneous.