Category Archives: lactic acid bacteria

Research – Effects of post‐packaging pasteurization process on microbial, chemical, and sensory qualities of ready‐to‐eat cured vacuum‐packed Turkey breast

Posted on June 27, 2020 by | Leave a comment

Wiley Online

Ready‐to‐eat (RTE) cured vacuum‐packed turkey breast was pasteurized (80°C, 5.5 min) and stored at 8°C (like supermarkets refrigerator temperature). After 42 days (current shelf life of this product), in control group (RTE cured vacuum‐packed turkey breast), the number of mesophilic, anaerobic, lactic acid bacteria, mold and yeast, coliform, and psychrotrophic increased 5.82, 6.85, 5.85, 4.75, 1.49, and 5.57 log CFU/g, respectively. However, in the pasteurized samples, the number of mesophilic, anaerobic, and lactic acid bacteria increased 1.86, 2.12, and 2.28 log CFU/g, respectively, and mold and yeast, coliform, and psychrotrophic bacteria were under the detection limit. The effects of post‐packaging pasteurization on the reduction of total mesophilic, anaerobic and lactic acid bacteria counts on Day 42 of storage was 7.04 ± 0.33, 4.73 ± 0.11, and 5.58 ± 0.11 log CFU/g, respectively. Sensory quality of treated samples was significantly better than the control’s (p  < .05). Post‐packaging pasteurization (PPP) significantly inhibited the reduction in the pH and the increase in TVB‐N, TBARS, titratable acidity, and drip loss (p  < .05). This study shows the effectiveness of PPP on microbial, chemical, and sensory quality of cured vacuum‐packed turkey breast during cold storage.

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Posted in Coliforms, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, lactic acid bacteria, microbial contamination, Microbiology, mold, Moulds, Research, Uncategorized, Yeasts

Research – Effects of post‐packaging pasteurization process on microbial, chemical, and sensory qualities of ready‐to‐eat cured vacuum‐packed Turkey breast

Posted on February 7, 2020 by | Leave a comment

Wiley Online

Ready‐to‐eat (RTE) cured vacuum‐packed turkey breast was pasteurized (80°C, 5.5 min) and stored at 8°C (like supermarkets refrigerator temperature). After 42 days (current shelf life of this product), in control group (RTE cured vacuum‐packed turkey breast), the number of mesophilic, anaerobic, lactic acid bacteria, mold and yeast, coliform, and psychrotrophic increased 5.82, 6.85, 5.85, 4.75, 1.49, and 5.57 log CFU/g, respectively. However, in the pasteurized samples, the number of mesophilic, anaerobic, and lactic acid bacteria increased 1.86, 2.12, and 2.28 log CFU/g, respectively, and mold and yeast, coliform, and psychrotrophic bacteria were under the detection limit. The effects of post‐packaging pasteurization on the reduction of total mesophilic, anaerobic and lactic acid bacteria counts on Day 42 of storage was 7.04 ± 0.33, 4.73 ± 0.11, and 5.58 ± 0.11 log CFU/g, respectively. Sensory quality of treated samples was significantly better than the control’s (p < .05). Post‐packaging pasteurization (PPP) significantly inhibited the reduction in the pH and the increase in TVB‐N, TBARS, titratable acidity, and drip loss (p < .05). This study shows the effectiveness of PPP on microbial, chemical, and sensory quality of cured vacuum‐packed turkey breast during cold storage.

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Posted in Coliforms, Food Micro Blog, Food Microbiology Blog, Food Microbiology Research, lactic acid bacteria, microbial contamination, Microbiology, mold, Moulds, Research, Uncategorized

Research – Mode of action of nisin on Escherichia coli

Posted on February 1, 2020 by | Leave a comment

nrc research 

Nisin is a class I polycyclic bacteriocin produced by the bacterium Lactococcus lactis, which is used extensively as a food additive to inhibit the growth of foodborne Gram-positive bacteria. Nisin also inhibits growth of Gram-negative bacteria when combined with membrane-disrupting chelators such as citric acid. To gain insight into nisin’s mode of action, we analyzed chemical–genetic interactions and identified nisin-sensitive Escherichia coli strains in the Keio library of knockout mutants. The most sensitive mutants fell into two main groups. The first group accords with the previously proposed mode of action based on studies with Gram-positive bacteria, whereby nisin interacts with factors involved in cell wall, membrane, envelope biogenesis. We identified an additional, novel mode of action for nisin based on the second group of sensitive mutants that involves cell cycle and DNA replication, recombination, and repair. Further analyses supported these two distinct modes of action.

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Posted in E.coli, Food Micro Blog, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, lactic acid bacteria, microbial contamination, Microbiology, Research, Uncategorized

Research – Use of Phyllosphere-Associated Lactic Acid Bacteria as Biocontrol Agents To Reduce Salmonella enterica Serovar Poona Growth on Cantaloupe Melons

Posted on January 2, 2020 by | Leave a comment

Journal of Food Protection

ABSTRACT

Foodborne illness associated with fresh, ready-to-eat produce continues to be a significant challenge to public health. In this study, we created a phyllosphere-associated lactic acid bacteria (PLAB) library and screened it via a high-throughput in vitro fluorescent assay to identify bacteria capable of inhibiting the growth of the pathogenic bacterium Salmonella enterica. One isolate, 14B4, inhibited the growth of S. enterica by >45-fold in vitro; it was able to grow and persist on the surfaces of cantaloupe melons at both ambient (25°C) and refrigerator (5°C) temperatures. Isolate 14B4 inhibited the growth of S. enterica on the surfaces of cantaloupes by >3 log when incubated at 25°C for 24 h and by >4 log when the cantaloupes were stored at 5°C for 3 days and the temperature was shifted to 25°C for 2 days. Genomic DNA sequence analysis of isolate 14B4 revealed that it was Lactococcus lactis and that it did not contain any known antibiotic biosynthesis gene clusters, antibiotic resistance genes, or genes encoding any known virulence factors. Organic acid analysis revealed that L. lactis produces substantial amounts of lactic acid, which is likely the inhibitory substance that reduced the growth of Salmonella on the cantaloupes.

HIGHLIGHTS

  • L. lactis isolate 14B4 inhibited the growth of Salmonella on cantaloupe rinds.

  • Storage of contaminated rinds at 5°C increased the growth inhibition by 1 log.

  • L. lactis isolate 14B4 is a potentially safe and effective biological control agent.

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Posted in food contamination, Food Hygiene, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Pathogen, Food Safety, Food Testing, lactic acid bacteria, Research, Salmonella, Uncategorized

Australia – Kienfat Trading Pty Ltd — Sriracha Hot Chilli Sauce 481g and 793g – Lactic Acid Bacteria

Posted on December 30, 2019 by | Leave a comment

Product Safety Australia

PRA No.
2019/18094
Date published
27 Dec 2019
Product description

Hot Chilli Sauce
Sriracha Hot Chilli Sauce 17oz (481g) and 28oz (793g)

Best Before MAR 2021

Photograph of Sriracha Hot Chilli Sauce

Identifying features

Other
APN/EAN 024463061095, 024463061163

What are the defects?

Lactic acid may build up, causing certain bottles to “bloat” and continue to ferment.

What are the hazards?

Food products with excessive pressure build up may splatter on to property or persons on opening, increasing the risk of injury.

What should consumers do?

Do not open bottles that feel “bloated”. Consumers should return the products to the place of purchase for a full cash refund.

For further information, contact Kienfat Trading Pty Ltd on 0412 012 362.

Supplier
Kienfat Trading Pty Ltd
Traders who sold this product

Asian Grocery Stores
Coles
IGA’s
Independent Grocery Stores
Woolworths

Where the product was sold
Nationally
Dates available for sale
  • 27 June 2019 – 27 December 2019

Recall advertisements and supporting documentation

Recall advertisement.pdf (300.06 KB)

Coordinating agency

Food Standards Australia New Zealand is the coordinating agency for this recall.

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Posted in food contamination, Food Hygiene, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Testing, food recall, Food Safety, Food Safety Alert, Food Spoilage, Food Testing, FSANZ, lactic acid bacteria, Uncategorized

Australia – Sriracha Hot Chilli Sauce 17oz and 28oz – Recall – Lactic Acid Bacteria

Posted on December 27, 2019 by | Leave a comment

FSANZ

26 December 2019

Product information

Kienfat Trading Pty Ltd is conducting a recall of Sriracha Hot Chilli Sauce 17oz and 28oz. The product has been available for sale at Coles, Woolworths, IGA’s, independent’s and Asian grocery stores nationally.

Date markings

Best Before MAR 2021

Problem

The recall is due to lactic acid build up causing certain bottles to “bloat” and continue to ferment.

Food safety hazard

Product may splatter on to property or persons on opening.

Country of origin

United States

What to do​

Do not open bottles that feel bloated and return the products to the place of purchase for a full refund.

For further information please contact:

Kienfat Trading Pty Ltd

​0412 012 362

Related links:

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Posted in food contamination, Food Hygiene, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Testing, food recall, Food Spoilage, Food Testing, FSANZ, lactic acid bacteria, Uncategorized

Research – Anti‐listeria activity and shelf life extension effects of Lactobacillus along with garlic extract in ground beef

Posted on October 14, 2019 by | Leave a comment

Wiley Online

The current study investigates the effect of Lactobacillus reuteri and Lactobacillus plantarum combined with water extract of garlic on microbial growth, chemical changes, and sensory attributes in ground beef samples at refrigeration condition (+4°C) up to 12 days of storage. in vitro study revealed that garlic extract combined with L. reuteri or L. plantarum caused 2.13 and 2.57 log reduction in the Listeria monocytogenes count, respectively. Combination of L. plantarum and 1% garlic extract significantly (p < .05) reduced aerobic mesophilic bacteria (1.64 log cycle) and L. monocytogenes (1.44 log cycle) counts in ground beef. Lipid oxidation was also significantly (p < .05) lower in samples treated with L. plantarum plus garlic extract (1%). Furthermore, higher sensory scores were received by samples treated with Lactobacillus plus garlic extract. In conclusion, the combination of L. plantarum and garlic extract was found to be suitable to use in ground beef by controlling the L. monocytogenes growth and increasing its shelf life.

Practical Applications

Garlic extract not only has an antimicrobial activity but also has a stimulatory effect on the Lactobacillus spp. growth. On the other hand, some Lactobacillus strains can inhibit pathogenic bacteria. Then, the combination of Lactobacillus and garlic extract may be used to produce new bio‐preserved and functional meat products. The current study indicated the potential of Lactobacillus combined with garlic extract to control microbial and chemical changes in ground beef. The combination of Lactobacillus plantarum and garlic extract significantly (p < .05) reduced Listeria monocytogenes counts and lipid oxidation rates and improved the sensory scores in ground beef.

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Posted in Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Technology, lactic acid bacteria, Lactobacillus, Listeria, Listeria monocytogenes, microbial contamination, Microbiology, Research, Technology, Uncategorized

Research – Culture-Independent Evaluation of Bacterial Contamination Patterns on Pig Carcasses at a Commercial Slaughter Facility

Posted on October 3, 2019 by | Leave a comment

Journal of Food Protection

ABSTRACT

Traditionally, the microbiological status of meat is determined by culture-based techniques, although many bacteria are not able to grow on conventional media. The aim of this study was to obtain quantitative data on total bacterial cell equivalents, as well as taxa-specific abundances, on carcass surfaces during pig slaughter using quantitative real-time PCR. We evaluated microbial contamination patterns of total bacteria, Campylobacter, Escherichia coli, Lactobacillus group, Listeria monocytogenes, Salmonella, and Pseudomonas species throughout slaughtering and on different carcass areas. In addition, we compared contamination levels of breeding sow carcasses with fattening pig carcasses, and we assessed the efficacy of carcass polishing machines under two water amount conditions. Our results demonstrate that relevant meat-spoilage organisms show similar contamination patterns to total bacteria. The highest bacterial load was detected in the stunning chute (4.08 × 105 bacterial cell equivalents per cm2) but was reduced by 3 log levels after singeing and polishing (P < 0.001). It increased again significantly by a 4.73-fold change until the classification step. Levels of Campylobacter, Lactobacillus, and Pseudomonas species and of E. coli followed a similar trend but varied between 0 and 2.49 × 104 bacterial cell equivalents per cm2. Microbial levels did not vary significantly between sampled carcass areas for any analyzed taxa. Running the polishing machine with a low water amount proved to be less prone to microbial recontamination compared with a high water amount (17.07-fold change, P = 0.024). In the studied slaughterhouse, slaughter of breeding sows did not produce microbiologically safe meat products (>104 cells per cm2) and the implementation of specific hazard analysis critical control point systems for the slaughter of breeding sows should be considered. A larger cohort from different abattoirs is needed to confirm our results and determine whether this is universally valid.

HIGHLIGHTS

  • Spoilage bacteria maintain consistent populations throughout slaughtering.

  • Greater water volume during polishing creates higher bacterial populations on carcasses.

  • Microbial populations on breeding sows are higher compared with fattening pigs.

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Posted in Campylobacter, Food Micro Blog, Food Microbiology Blog, Food Microbiology Research, Food Technology, lactic acid bacteria, Listeria monocytogenes, microbial contamination, Microbiology, Pseudomonas, Research, Salmonella, Technology, Uncategorized

Research – Microbial Status of White Asparagus Spears during Storage in Moist Packages

Posted on September 5, 2019 by | Leave a comment

Journal Food Protection

ABSTRACT

White asparagus is a high-value commodity of large economic importance in Germany. Its harvest period lasts only a limited part of the year, during which daily yield and also market demand are highly variable. Harvested asparagus is perishable; thus, quality control and shelf life must be ensured by proper handling, e.g., avoiding fresh weight losses and, at the same time, limiting microbial growth. The aim of this study was to determine the effect of moist asparagus packaging on unpeeled white asparagus (cv. Gijnlim). Water was added to some of the packages to reduce fresh weight losses and to study the consequences for microbial growth. Polythene bag packaging, lined inside with cellulose fleece, was used to hold 500-g bunches of spears, covered partly (open bag) or totally (closed bag). Storage duration was 7 days, at temperatures of 2°C, 8°C, and a combination of 2 and 22°C, simulating retail conditions. Using a standardized cultivation method for food assessment, CFU counts (5.20 to 7.95 log CFU), number of pseudomonads (4.79 to 7.90 log CFU), lactic acid bacteria (<3.00 to 3.94 log CFU), Enterobacteriaceae (4.26 to 7.15 log CFU, including Escherichia coli <1.00 log CFU), yeasts (<2.30 to 3.15 to 3.53 log CFU), and molds (<2.30 log CFU), as well as sulfite-reducing clostridia (<1 log CFU) were determined. Temperature was the most important factor for microbial growth. Additional water had no effect in most cases; it inhibited most of the fresh weight losses compared to dry treatments in this study but led to 2% weight increase in closed bags. Our results point to the conclusion that moist packaging would be a feasible alternative to dry wrapping with regard to weight retention, and it did not increase growth of the analyzed microbial groups to an unacceptable value.

HIGHLIGHTS

  • Moist packaging of white asparagus does not necessarily increase microbial load after storage.

  • Microbial counts were lower after 1 week of storage in a closed versus open package.

  • Microbial growth did not exceed tolerable values.

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Posted in E.coli, Enterobacteriaceae, Food Micro Blog, Food Microbiology Blog, Food Technology, lactic acid bacteria, microbial contamination, Microbiology, mold, Sulphite Reducing Clostridia, Technology, Uncategorized

Research – Effects of Sodium Chloride or Calcium Chloride Concentration on the Growth and Survival of Escherichia coli O157:H7 in Model Vegetable Fermentations

Posted on March 31, 2019 by | Leave a comment

Journal of Food Protection

Salt concentration has long been considered an important factor for the quality of fermented vegetable products, but the role of salts in bacterial growth and death during vegetable fermentation remains unclear. We compared the effects of various sodium chloride (NaCl) concentrations, including 1 M (6%) NaCl used in commercial cucumber fermentations and 0.34 M (2%) NaCl used in cabbage and other ready-to-eat vegetable fermentations, on the growth and death of lactic acid bacteria (LAB) of the genus Lactobacillus and pathogenic Escherichia coli (Shiga toxin–producing E. coli, or STEC) strains. We also investigated calcium chloride (CaCl2) salt conditions. CaCl2 is being used at 0.1 M (1.1%) in low-salt commercial cucumber fermentations that lack added NaCl. STEC strains have previously been shown to be among the most acid-resistant pathogens in fermented or acidified vegetables. The data showed that 1.1% CaCl2, and especially 1% NaCl, had a stimulatory effect on the growth rates of STEC and LAB compared with a no-salt control, but higher NaCl concentrations decreased growth rates for STEC; to a lesser extent, LAB growth rates were also reduced. For most salt concentrations tested, maximum cell densities achieved during growth of STEC were reduced compared with those of the no-salt controls, whereas LAB mostly had cell densities that were similar to or greater than those of the no-salt controls. No consistent pattern was observed when comparing death rates with salt type or concentration for the STEC or LAB cocktails undergoing lactic acid stress (50 or 350 mM, respectively) at pH 3.2 and when comparing STEC survival in competitive culture experiments with LAB. For vegetable fermentation safety concerns, the results suggest that an important effect of salt addition is enhancement of the growth of LAB compared with STEC strains. Further research will be needed to determine factors influencing STEC survival in competition with LAB in vegetable fermentations.

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Posted in E.coli, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Technology, Food Testing, lactic acid bacteria, microbial contamination, STEC, Uncategorized