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PubMed2001

The control of VTEC in the animal reservoir.

A great diversity of VTECs exist but only in the case of Escherichia coli O157:H7, a common human foodborne pathogen, has sufficient research been done to allow generalizations about the ecology. The key features are as follows: lack of host specificity such that indistinguishable isolates can be found in a variety of species; near-ubiquitous distribution in cattle (and perhaps other ruminant) farms; transient residence in the gastrointestinal flora of individual animals that is not associated with clinical disease; temporal clustering at the population level such that most fecal shedding is confined to sharp bursts in a high percentage of animals separated by much longer periods of very low prevalence; a higher prevalence in young animals in comparison to older ones: a higher prevalence in animals with floral disturbance such as that caused by transit, feed changes or antimicrobial dosing; and a markedly higher prevalence during warm months. Molecular epidemiological studies of E. coli O157:H7 have demonstrated that subtypes of the organism can persist on cattle farms for years, thus supporting a conclusion that cattle farms represent a reservoir. Yet on such farms, common subtypes are often found in environmental niches and in other species of animals; thus, it is not completely clear that cattle themselves are the reservoir. New subtypes are periodically observed on particular farms, and indistinguishable subtypes can be found on farms that are separated by hundreds of kilometers even in the absence of any obvious animal movements between them. The number of subtypes found on a farm does not appear to be qualitatively correlated with cattle movements (e.g., purchases) into the farm. Commercial feeds are sometimes contaminated with E. coli O157:H7, and it seems likely that feeds represent an important route of dissemination for this agent and other VTEC. Mixed feeds collected from feeding troughs are commonly positive for E. coli O157:H7, as are cattle watering troughs, and feed and water likely represent the most common means of infection. Environmental replication in feeds and in sediments of watering troughs occurs and may account for the higher level of fecal shedding in the warm months. Since E. coli O157:H7 has been found to persist and remain infective for at least 6 months in water trough sediments, this may be an important environmental niche where the organism survives during periods when it cannot be detected in cattle, especially during cold months. Traditional means of controlling infectious agents, such as eradication or test and removal of carrier animals, do not appear to be feasible for VTECs. Nevertheless, certain farm management practices-especially those related to maintenance and multiplication of the agent in feed and water-may provide practical means to substantially reduce the prevalence of these agents in cattle on farms and in those arriving at slaughter plants.

Age Factors↗

PubMed2001

Antibacterial effect of protamine in combination with EDTA and refrigeration.

The antimicrobial effect of protamine (clupeine) on a range of gram-positive and gram-negative foodborne pathogens and spoilage bacteria, was evaluated using an agar dilution assay and a broth dilution assay with Alamar Blue as growth indicator. Protamine was tested alone at concentrations from 0 to 10,000 microg/ml, and in combination with EDTA (0.9 mM). Assays were performed at 5 degrees C, 10 degrees C, 18 degrees C and 30 degrees C to test the effect of temperature. Minimum inhibitory concentration (MIC) values ranged from 10 microg/ml for Brochothrix thermosphacta to no inhibition at 10,000 microg/ml for bacteria such as Aeromonas hydrophila, proteolytic strains of Clostridium botulinum, Hafnia alvei and Morganella morganii. The minimum bactericidal concentrations (MBCs) were generally higher than MICs. In combination with EDTA, MICs of protamine decreased for gram-negative test strains, whereas EDTA alone inhibited gram-positive strains. The effect of assay incubation temperature was variable and not clear for most strains. Concentrations of 100-750 microg/ml protamine inhibited the five non-proteolytic C. botulinum strains, while none of the eight proteolytic strains was inhibited, indicating the possible role of proteolytic enzymes in protecting cells from protamine. Clearing zones, indicative of proteolytic activity, were observed in the opaque TSB-agarose around colonies of some but not all protamine-resistant bacteria, suggesting that this is not the only resistance mechanism. Addition of 5% (w/v) gelatin to study the effect of an increased protein concentration in the agar dilution assay showed that electrostatic interactions between protamine and the protein decreased the antimicrobial efficacy of the peptide.

Clupeine↗

PubMed2001

Isolation and polymerase chain reaction-based detection of Campylobacter jejuni and Campylobacter coli from poultry in the Philippines.

The polymerase chain reaction (PCR) and the conventional culture method of detecting thermophilic Campylobacter species in duck and chicken samples from two locations in the province of Laguna, Philippines, were compared. Three Campylobacter jejuni and five C. coli strains were isolated from a total of 135 duck and chicken samples from both methods. The PCR technique, however, was found to be more sensitive, accurate and rapid than the conventional culture method. The specificity of two sets of published primers, C442-C490 (specific for C. jejuni, C. coli and C. lari) and CL2-CR3 (specific for C. jejuni) were confirmed with reference and field strains. To improve detection, a lysate was prepared by boiling cells in Triton X-100, and then used as template for PCR to detect Campylobacter from spiked and naturally contaminated chicken rinse. For spiked chicken samples, a 17-h Meuller-Hinton Broth enrichment for the chicken rinse resulted in an improved sensitivity at 31.7 CFU/g using C442-C490. This enrichment-PCR tandem also detected thermophilic Campylobacter from 1 out of 21 native chicken samples from a wet market. To our knowledge, this is the first report of thermophilic Campylobacter isolation from poultry in the Philippines. The approaches described here could serve as a basis for future surveillance and/or epidemiological studies on this emerging foodborne pathogen.

Animals↗

PubMed2002

Molecular typing techniques to characterize the development of a lactic acid bacteria community on vacuum-packaged beef.

The development of a community of lactic acid bacteria from vacuum-packaged beef was investigated during a 6-week storage trial at 2 degrees C. The lactic acid bacteria population was monitored by using molecular techniques to identify a random sample of isolates at biweekly intervals during the storage trial. The polymerase chain reaction and a randomly amplified polymorphic DNA technique were used to identify and distinguish populations of lactic acid bacteria that developed during the storage trial. At week 0, the population of lactic acid bacteria was 3.5 log cfu/120 cm2 and by week 6, the population reached a maximum of 7.6 log cfu/120 cm2. A sampling from the week 0 population indicated a mixed community of Lactobacillus curvatus, Lactobacillus sakei and Leuconostoc spp. However, the sampling from week 6 indicated the population composition had changed to one where a single Leuconostoc strain predominated. This strain demonstrated antagonism towards the growth of other lactic acid bacteria isolated during the study. Additionally, the strain inhibited the growth of foodborne pathogens Escherichia coli O157:H7 and Listeria monocytogenes. DNA sequence data from the 16S rRNA gene suggested that the isolate may be a Leuconostoc gelidum strain.

Animals↗

PubMed2002

A novel area of predictive modelling: describing the functionality of beneficial microorganisms in foods.

Predictive microbiology generally focuses on the potential outgrowth of spoilage bacteria and foodborne pathogens in foods. Little attention has been paid to the biokinetics of beneficial foodgrade microorganisms, such as lactic acid bacteria. The latter is commonly used in the food fermentation industry, mainly for the in situ production of the antimicrobial lactic acid to extend the shelf life of the food. Furthermore, many strains show additional industrial potential as novel starter cultures since they produce functional metabolites, such as bacteriocins and exopolysaccharides. The production of these functional metabolites has been demonstrated during in vitro experiments, but in many cases these novel starter cultures seem to be less efficient when applied in a food system. A modelling approach may contribute to a better understanding of the tight relation between the food environment and bacterial functionality. Primary modelling can be applied to fit the experimental data concerning cell growth, sugar metabolism, and the production of functional metabolites for a given set of environmental conditions. This led to conclusions concerning the growth-associated production of bacteriocin and exopolysaccharides, the inactivation of these molecules when cell growth levels off, and a minimum cell concentration to trigger on bacteriocin production. Examples deal with the production of the bacteriocin sakacin K by the natural fermented sausage isolate Lactobacillus sakei CTC 494, and the production of heteropolysaccharides by the yoghurt starter culture Streptococcus thermophilus LY03. Secondary modelling of biokinetic parameters quantifies the production of bacteriocin and exopolysaccharides in function of environmental factors. As an example, the specific bacteriocin production by Lb. sakei CTC 494 decreases with increasing sodium chloride concentrations. Furthermore, since the assessment of functionality is frequently hampered by the nature of the food system, mathematical modelling techniques may help to predict the functional behaviour of novel lactic acid bacteria starter cultures in a food matrix, and hence quantify in situ production. For example, a model may simulate cell growth and exopolysaccharide production of S. thermophilus LY03 in a milk environment, where direct measurements are difficult to perform.

Bacteriocins↗

PubMed2002

Variation among Escherichia coli O157:H7 strains relative to their growth, survival, thermal inactivation, and toxin production in broth.

To estimate the potential outcomes of food processing on the fate of foodborne pathogens. variations in microbial parameters such as growth rate, survival time, thermal inactivation time, and toxin production must be known. Previous microbial studies using single strains or cocktails provide error estimates for the uncertainty of the experimental and statistical procedures, but not for variations among strains. In this study, the behavior of 17 strains of Escherichia coli O157:H7 were followed when placed in synthetic media that permitted growth, survival, or thermal inactivation. The parameter values were not rejected as being normal, lognormal, gamma, or Weibull distributions. The ratio of the standard deviation to mean (normal distribution) for the exponential growth rate was 0.16 and for the lag phase duration, it was 0.38. The ratios of times to achieve a 4-log10 reduction at two survival conditions were 0.39 and 0.46; ratios of thermal D values at 55 and 60 degrees C were 0.42 and 0.33, respectively. The ratio of the negative log10 of toxin production was 0.24. These distributions are larger than the coefficient of variations observed for experimental errors in single strain and cocktail experiments. This indicates the limitations in precision that predictions of future population numbers can have when the potential presence of all strains needs to be considered. This variation among strains is applicable whether predictions are made by traditional subjective and point estimates or by using models and risk assessments.

Bacterial Toxins↗

PubMed2002

Spectral surface plasmon resonance biosensor for detection of staphylococcal enterotoxin B in milk.

This work evaluates a newly developed wavelength modulation-based SPR biosensor for the detection of staphylococcal enterotoxin B (SEB) in milk. Two modes of operation of the SPR biosensor are described: direct detection of SEB and sandwich assay. In the sandwich assay detection mode, secondary antibodies are bound to the already captured toxin to amplify sensor response. Samples including SEB in buffer and SEB in milk were analyzed in this work. The SPR biosensor has been shown to be capable of directly detecting concentrations of SEB in buffer as low as 5 ng/ml. In sandwich detection mode, the lowest detection limit was determined to be 0.5 ng/ml for both buffer and milk samples. The reported wavelength modulation-based SPR sensor provides a generic platform which can be tailored for detection of various foodborne pathogens and agents for food analysis and testing.

Animals↗

PubMed2002

Sodium chloride decreases the bacteriocidal effect of acid pH on Escherichia coli O157:H45.

To reduce the risk of foodborne illness, many fermented and minimally processed foods rely on the "hurdle effect", i.e. a combination of two or more inhibitory agents being more inhibitory than any of the agents alone. However, we have observed that such a combination of agents is not always more inhibitory to foodborne pathogens than one alone. In this paper, we show that a combination of NaCl and acid pH is less effective than acid pH alone in reducing the numbers of Escherichia coli O157:H45. The presence of sodium chloride reduces the bacteriocidal effect of lactic acid on logarithmically growing cells of E. coli O157:H45. with approximately 10(3)-fold more survivors at pH(o) 4.2 when 4% NaCl was added to the medium. A similar protective effect was also seen with other organic acidulants and E. coli strains. The cytoplasmic pH (pH(i)) of cells in medium at pH 4.2 containing added salt was 5.8 which was 0.56 units higher than that of cells in the same medium without added salt. When the pH(i) of cells in medium without added salt was adjusted to the same value (5.8) by adding KOH, the rate of survival was also considerably greater than that of cells in medium without added salt. These data suggest that E. coli can use NaCl to counteract acidification of its cytoplasm by organic acids, and in addition, that combinations of antimicrobial agents cannot always be relied upon to achieve additive antimicrobial effects.

Cytoplasm↗

PubMed2002

Prevalence and numbers of Salmonella and Campylobacter spp. on raw, whole chickens in relation to sampling methods.

Salmonella and Campylobacter continue to be major foodborne pathogens and raw poultry is considered to be an important source of these bacteria. In this study, the prevalence and numbers of Salmonella and Campylobacter spp. in relation to isolation/sampling methods were determined in 241 whole raw chickens purchased from retail outlets in England during the winters of 1998/1999 (101 chickens) and 1999/2000 (140 chickens). The packaging of the 140 chickens was also examined for the presence of the above pathogens. The prevalence and numbers of enterococci were examined in 21 of the 101 chickens. In total, Salmonella and Campylobacter spp. were present in 25% and 83% of the chickens, respectively. Salmonella were isolated from a sample representing both the inside and outside of the packaging in 19% of the chickens, while the corresponding figure for Campylobacter spp. was 56%. Both of these pathogens were isolated from the outside of the packaging in 6% of the chickens. Salmonella was more frequently isolated from samples containing chicken skin in comparison with those containing carcass-rinse fluid only. Two chickens (0.8%) were positive for Salmonella by direct enumeration methods with contamination levels of log10 3.8 and 4.5 colony forming units (cfu) per carcass, respectively. The most prevalent serotypes were S. Hadar, S. Enteritidis and S. Indiana and two different serotypes were identified in 5/20 salmonella-positive chickens. Resistance to at least one antibiotic was found in 70% of the strains, 46% were multiresistant (resistant to > or = four drugs) and 52% showed a lowered susceptibility to ciprofloxacin. The likelihood of isolating Campylobacter spp. from neck-skin, carcass-rinse or carcass-rinse plus whole skin samples was similar, Campylobacter spp. were found in higher levels in carcass-rinse or carcass-rinse plus whole skin samples than in neck-skin. The log10 cfu of Campylobacter spp. were 2.70-4.99 in 18% of the chickens and 5.00-6.99 in 20%. Campylobacter isolates (425) comprised Campylobacter jejuni (98%) and C. coli (2%) and 98 different sero/phagetypes of these two species were identified. Resistance to at least one antibiotic was found in 73% of the strains and 13% were multiresistant. Thirteen percent of the strains showed lowered susceptibility to ciprofloxacin, while 4.9% were resistant to erythromycin. Vancomycin-resistant enterococci (VRE), able to grow on agar containing 15 mg l(-1) vancomycin (VRE15), were present in 19 chickens. The log10 cfu of VRE15 was 2.90-3.99 in 10 chickens and between 4.00 and 4.99 in two chickens. The data presented here contribute to risk assessment and highlight the need to continue to emphasise the safe handling of raw retail poultry.

Animals↗

PubMed2003

Characterization and heterologous expression of a class IIa bacteriocin, plantaricin 423 from Lactobacillus plantarum 423, in Saccharomyces cerevisiae.

Lactobacillus plantarum 423 produces a small heat-stable antimicrobial protein designated plantaricin 423. This protein is bactericidal for many Gram-positive foodborne pathogens and spoilage bacteria, including Listeria spp., Staphylococcus spp., Pediococcus spp., Lactobacillus spp., etc. The DNA sequence of the plantaricin 423-encoding region on plasmid pPLA4 revealed a four open reading frame (ORF) operon structure similar to pediocin PA-1/AcH from Pediococcus acidilactici and coagulin from Bacillus coagulans I(4). The first ORF, plaA, encodes a 56-amino acid prepeptide consisting of a 37-amino acid mature molecule, with a 19-amino acid N-terminal leader peptide. The second ORF, plaB, encodes a putative immunity protein with protein sequence similarities to several bacteriocin immunity proteins. The plaC and plaD genes are virtually identical to pedC and pedD of the pediocin PA-1 operon, as well as coaC and coaD of the coagulin operon. Plantaricin 423 was cloned on a shuttle vector under the control of a yeast promoter and heterologously produced in Saccharomyces cerevisiae.

Amino Acid Sequence↗

PubMed2002

Acid tolerance response is low-pH and late-stationary growth phase inducible in Bacillus cereus TZ415.

The acid tolerance of foodborne pathogen Bacillus cereus TZ415 was examined. B. cereus was more tolerant to an acid challenge at pH 4.0 when cells were grown at low pH in regulated batch cultures of rich J Broth (JB) medium. The pH-inducible acid tolerance response (ATR) was maximal at pH 5.0, a sublethal growth condition inducing a remarkable cell elongation. During growth at regulated pH 7.0 and 6.0, B. cereus TZ415 became more acid sensitive from lag to stationary growth phase and the acid tolerance of cells reached its maximum level in late-stationary growth phase. The ATR induced at pH 5.5 and 5.0 was not affected by growth phase. Cellular protein profiles were analysed as a function of growth phase and medium pH. The Hemolysin BL (HBL) enterotoxin was only detected when cells were grown at pH 7.0.

Bacillus cereus↗

PubMed2003

Rapid urease screening of Yersinia on CIN agar plates.

Yersinia enterocolitica is an important foodborne pathogen, but isolation of virulent Yersinia from food sources is still time consuming and requires skills. In this article, we describe a rapid urease screening on cefsulodin-irgasan-novobiocin (CIN) agar plates with an agar overlay assay. This test is simple to perform, all colonies on a plate can be checked simultaneously, it only takes minutes for detection of urease-positive colonies and the colonies survive for transfer, further characterisation, and storage. Additionally, this method is useful to isolate virulent (urease-positive and pYV harbouring) Y. enterocolitica from foodstuffs.

Agar↗

PubMed2003

The effect of processed meat and meat starter cultures on gastrointestinal colonization and virulence of Listeria monocytogenes in mice.

Listeria monocytogenes is a foodborne pathogen of major concern to the food industry in general and the meat industry in particular. The aim of this study was firstly to identify a strain of Listeria that was virulent in SPF BALB/c mice. Secondly, to investigate if a traditional meat starter culture (FloraCarn) and nontraditional meat starter (NTMS) cultures of dairy product and human origin (Lactobacillus and bifidobacteria) inhibit this pathogen in vivo. In addition, the inhibition of Listeria was investigated in vitro. In vitro inhibition was investigated using an agar inhibition assay, where soft agar containing the pathogen was laid over colonies of NTMS cultures, and inhibition expressed as the zones of inhibition developing around the colonies. For assessment of virulence, mice were intragastrically challenged with broth cultures of five strains of Listeria. For assessment of anti-listeria effect in vivo, the Listeria strain proven to be most pathogenic (LM3) was given to mice in salami batter containing no other added cultures (control) or batter inoculated with either (1) FloraCarn, (2) a NTMS culture, or (3) a combination of FloraCarn and a NTMS culture. The batter was given to mice after a 3-day fermentation and faecal levels of pathogen and body weight were monitored. Intragastric challenge with LM3, but no other strains, resulted in a significant weight loss (p<0.05) and up to 10(6) colony forming units (cfu) of LM3 per gram faeces. No weight loss was observed in animals fed with salami batter containing LM3. Consumption of salami batter fermented by a combination of NTMS culture (Lactobacillus acidophilus LAFTI(R) L10) and FloraCarn reduced faecal levels of the pathogen by 2.5 log units compared to the control. Consumption of salami batter fermented with FloraCarn and LAFTI(R) L10 (L10) alone reduced faecal levels by 0.5-1 and 1.5 log units, respectively. Of the NTMS cultures investigated here, L10 displayed the greatest inhibition of LM3 in vitro. These results indicate that the ability of pathogenic Listeria to cause listeriosis is dependent on the nature of the food in which the pathogen is present, and that a traditional meat starter culture (FloraCarn) and some NTMS cultures, particularly L10, inhibit growth of the pathogen during passage through the gastrointestinal tract.

Animals↗

PubMed2003

Extraction methods for lipopolysaccharides from Escherichia coli ATCC 25922 for quantitative analysis by capillary electrophoresis.

Lipopolysaccharides (LPS) are major constituents of the cell wall of Gram-negative bacteria. Capillary zone electrophoresis (CZE) was applied to distinguish between lipopolysaccharides extracted from Escherichia coli ATCC 25922 with various techniques. Extraction methods proposed by Westphal and Jann [Methods Carbohydr. Chem. 5 (1965) 83], Galanos et al. [Eur. J. Biochem. 9 (1969) 245], Ni Eidhin and Mouton [FEMS Microbiol. Lett. 110 (1993) 133] and Nichols [Infect. Immun. 62 (1994) 3753] for LPS preparation were evaluated. Electrophoresis buffers with varying pHs were applied to assess the structure stability of the extracted LPS samples. Variations in structural breakdown were apparent demonstrating that different extraction methods removed different LPS molecules. Furthermore, the results obtained proved the CZE useful as an analytical technique for LPS evaluation. The LPS removed with the Nichols extraction procedure presented a unique electrophorogram that could in future be applied in the rapid identification of Gram-negative foodborne pathogens.

Electrophoresis, Capillary↗

PubMed2003

Antibacterial activity of 11 essential oils against Bacillus cereus in tyndallized carrot broth.

The antibacterial activity of 11 essential oils from aromatic plants against the strain INRA L2104 of the foodborne pathogen Bacillus cereus grown in carrot broth at 16 degrees C was studied. The quantity needed by the essential oils of nutmeg, mint, clove, oregano, cinnamon, sassafras, sage, thyme or rosemary to produce 14-1110% relative extension of the lag phase was determined. Total growth inhibition of bacterial spores was observed for some of the antimicrobial agents assayed. The addition of 5 microl cinnamon essential oil per 100 ml of broth in combination with refrigeration temperatures of <or=8 degrees C produced the conditions necessary to inhibit the growth of B. cereus for at least 60 days in a model, refrigerated minimally processed food product, made with carrots and tyndallized. This is especially important considering that the psychrotrophic enterotoxigenic strain of B. cereus INRA TZ415 was able to grow in this substrate at low temperatures in the absence of any essential oil. Furthermore, the study of the sensory characteristics of the final product suggests that the use of cinnamon essential oil can be considered as an alternative to "traditional food preservatives".

Bacillus cereus↗

PubMed2003

Dynamic computer simulation of Clostridium perfringens growth in cooked ground beef.

The objective of this study was to develop a computer simulation algorithm to dynamically estimate and predict the growth of Clostridium perfringens in cooked ground beef. The computational algorithm was based on the implicit form of the Gompertz model, the growth kinetics of C. perfringens in cooked ground beef, and the fourth-order Runge-Kutta numerical method. This algorithm was validated using a cocktail of three strains of C. perfringens spores grown under isothermal, square-waved, linear cooling, and exponential cooling temperature profiles. In general, the results of computer simulation matched closely with the experimental data with the absolute errors less than 0.5 log(10) CFU/g. This method may be a useful tool for the food industry, regulatory agencies, distributors, and retailers to predict the effect of temperature abuse on the microbial safety of C. perfringens and other foodborne pathogens in processed meat products.

Animals↗

PubMed2004

Inhibition of foodborne bacteria by the lactoperoxidase system in a beef cube system.

Biopreservatives are being developed to inhibit the growth of foodborne pathogens and thus improve food safety. The lactoperoxidase system (LPS) is a naturally occurring system that has potential for use as an antimicrobial agent in foods. Growth of single strains of the pathogens Staphylococcus aureus, Listeria monocytogenes, Escherichia coli O157:H7, Salmonella enterica subsp. enterica serovar Typhimurium, Yersinia enterocolitica, Pseudomonas aeruginosa and beef microflora were assessed on LPS-treated meat surfaces in an experimental system. Beef cubes inoculated with approximately 10(4) cfu cm(-2) of bacteria were treated with the LPS and incubated at 37 degrees C for 24 h, 12 degrees C for 7 days or in a chilling regime: 12 to -1 degrees C over 1 week and held at -1 degrees C for 4 weeks. Treatment with LPS was more effective at storage temperatures non-permissive for rapid bacterial growth with strong inhibition of growth achieved on LPS-treated cubes at 12 degrees C and reduction in pathogen viable counts at chilling temperatures. At chilling temperatures, the LPS inhibited the growth of native pseudomonads but did not prevent the development of native lactic acid bacteria.

Animals↗

PubMed1998

Plantaricin LP84, a broad spectrum heat-stable bacteriocin of Lactobacillus plantarum NCIM 2084 produced in a simple glucose broth medium.

Lactobacillus plantarum NCIM 2084 produced an antibacterial substance when grown at 40 degrees C for 36 h in a laboratory medium. The antibacterial substance was active against a wide range of bacteria comprising Gram positive and negative foodborne pathogenic and spoilage bacteria. However, related mesophilic lactobacilli were not inhibited, except for L. amylovorus DSM 20531. The antimicrobial activity was observed between late log and stationary growth phases. The antibacterial substance was partially purified through concentration under vacuum, followed by extraction with methanol and acetone (M-A extract). On fractionation of the M-A extract through Sephadex G-25, the activity was present in an eluant volume of 85 to 100 ml (peak I), indicating an apparent molecular mass of between 1 and 5 kDa and the purification attained was 80-fold. The antimicrobial principle was stable to heat (121 degrees C for 20 min) and catalase, but sensitive to trypsin and chymotrypsin, indicating it to be a bacteriocin. The M-A extract exhibited a bactericidal and lytic effect against Bacillus cereus F 4810 and Escherichia coli D 21. The ability of L. plantarum NCIM 2084 to produce an effective bacteriocin in a simple growth medium is of potential interest in its application as a biopreservative in traditional fermented foods.

Bacteriocins↗