Category Archives: Bio-Preservative

Research – Simple lab-free test to detect bacteria in fluids from water to urine

Science Daily

A novel new test for bacteria in fluids makes it as easy as observing a colour change to confirm the presence of disease-causing pathogens, promising much easier diagnostic tests and greater food safety.

Engineers and biochemists at McMaster university have brought their skills together to make it possible for untrained users to confirm contamination in fluids using a biogel test that changes colour in the presence of such bacteria as E. coli, listeria and other frequent testing targets.

The test uses harmless bacteriophages embedded in the gel to locate target bacteria in a sample of fluid such as lake water, urine or a container of milk, even in low concentrations.

Bacteriophages are the most common form of life on Earth. Each form of bacteriophage is specialized to destroy one form of bacteria.

Research – Effects of Sodium Chloride, Sodium Lactate, and Sodium Diacetate on the Growth Probabilities of Salmonella Spp. and Staphylococcus Aureus

Wiley Online

ABSTRACT

Salmonella spp. and Staphylococcus aureus have been linked to foodborne illnesses caused by the consumption of processed meat products. This study examined the growth probabilities of these two pathogens as affected by sodium chloride (salt), sodium lactate, and sodium diacetate in a solid medium for using these three additives to improve the microbial safety of processed meat. Sterilized tryptic soy agar (TSA, 200 μL) formulated with a combination of salt (3%–8%, aw 0.98–0.93), lactate (0%–2.4%), and diacetate (0%–0.25%) and inoculated with Salmonella spp. or S. aureus was dispersed into 96-well microplates and incubated at 37°C for 7 days. After incubation, a well showing any Salmonella spp. or S. aureus colonies was denoted as a growth event, otherwise a no-growth event. The number of growth events for each formulation was recorded. The effects of the additives on the growth event were analyzed by logistic regression to identify the growth and no-growth boundaries and the formulations that may prevent the growth of Salmonella spp. or S. aureus. For Salmonella spp., the observed minimum no-growth concentrations in TSA were 3% salt with 0.8% lactate+0.2% diacetate or 1.6% lactate+0.1% diacetate, 4% salt with 2.4% lactate, 5% salt with 0.25% diacetate, 6% salt with 0.8% lactate+0.15% diacetate, 7% salt with 0.8% lactate or 0.15% diacetate, and 8% salt alone. For S. aureus, the concentrations were 3% salt with 2.4% lactate+0.2 diacetate, 5% salt with 1.6% lactate+0.2% diacetate, 7% salt with 0.8% lactate+0.25% diacetate, and 8% salt with 0.8% lactate+0.20% diacetate or 1.6% lactate+0.15% diacetate. These no-growth formulations also inhibited the growth of both pathogens in cooked meat samples. Mathematical models were developed to describe the effects of the additives on the growth probabilities of Salmonella spp. and S. aureus. Findings from this study may be used for formulating refrigerated and shelf-stable meat products to reduce Salmonella spp. and S. aureus risk.

Research – Antibacterial Activity of Phloretin Against Vibrio parahaemolyticus and Its Application in Seafood

MDPI

Abstract

Although phloretin is widely utilized in the food industry as an additive, its effects on foodborne pathogens remain insufficiently investigated. This study aimed to evaluate the antimicrobial properties of phloretin (PHL) against Vibrio parahaemolyticus (V. parahaemolyticus) and to elucidate the potential mechanisms of action. After PHL treatment, alterations in the cell morphology, cell microstructure, and intracellular contents of V. parahaemolyticus were assessed. Scanning electron microscopy revealed substantial damage to cell integrity, subsequent to PHL treatment. A notable reduction in intracellular components, including proteins, ATP, and DNA, was observed in samples treated with PHL. PHL was shown to inhibit the activities of ATPase, β-galactosidase, and respiratory chain dehydrogenase in V. parahaemolyticus. Furthermore, it was demonstrated to elevate the intracellular levels of reactive oxygen species and promote cell death. After being applied to sea bass, shrimp, and oysters, PHL effectively inactivated V. parahaemolyticus in these seafoods. These findings demonstrate that PHL has potential for application in seafood to control V. parahaemolyticus.

Research – Food processing aid against Listeria gets approval for use in the U.S. market

Food Safety News

This innovative technology, developed by Canadian biotechnology company Innodal, uses antimicrobial peptides to eliminate the harmful pathogen.  With its entry into the U.S. market, Innodal is set to launch industrial-scale projects with U.S. processing companies.

Listeria monocytogenes is feared by public health because it potentially has a high mortality rate. In a 2008 Canadian outbreak, that rate approached 40 percent.

INNEO is  Innodal’s flagship product.  It has been successfully commercialized in Canada for four years and will now be available in the U.S. market. Designed to target Listeria monocytogenes — a severe foodborne pathogen responsible for listeriosis — INNEO has proven significantly more effective than traditional chemical treatments in industry trials, particularly against strains that have led to major recalls in North America.

Research – Berry Pomace Extracts as a Natural Washing Aid to Mitigate Enterohaemorrhagic E. coli in Fresh Produce

MDPI

Abstract

Enterohemorrhagic Escherichia coli (EHEC) outbreaks have been frequently linked to the consumption of produce. Furthermore, produce grown on organic farms possess a higher risk, as the farmers avoid antibiotics and chemicals. This study sets out to evaluate the effectiveness of advanced postharvest disinfection processes using berry pomace extracts (BPEs) in reducing EHEC load in two common leafy greens, spinach and lettuce. Spinach and lettuce were inoculated with ~5 log CFU/leaf EHEC EDL-933 and then treated with three different concentrations of BPE (1, 1.5, and 2 gallic acid equivalent, GAE mg/mL) for increasing periods of time. After the wash, the bacteria were quantified. Changes in the relative expression of virulence genes and the genes involved in cell division and replication and response against stress/antibiotics were studied. We observed a significant reduction in EHEC EDL933, ranging from 0.5 to 1.6 log CFU/spinach leaf (p < 0.05) washed with BPE water. A similar trend of reduction, ranging from 0.3 to 1.3 log CFU/mL, was observed in pre-inoculated lettuce washed with BPE water. We also quantified the remaining bacterial population in the residual treatment solutions and found the survived bacterial cells (~3 log CFU/mL) were low despite repeated washing with the same solution. In addition, we evaluated the phenolic concentration in leftover BPE, which did not change significantly, even after multiple uses. Alterations in gene expression levels were observed, with downregulation ranging from 1 to 3 log folds in the genes responsible for the adhesion and virulence of EHEC EDL933 and significant upregulation of genes responsible for survival against stress. All other genes were upregulated, ranging from 2 to 7 log folds, with a dose-dependent decrease in expression. This finding shows the potential of BPE to be used for sanitation of fresh produce as a natural and sustainable approach.

Research – Efficacy of organic acids, lactic and formic acid, and peracetic acid in decontaminating process water and carcasses in chicken slaughter

Wiley Online

Abstract

Foodborne pathogens pose a persistent threat in broiler chicken production, particularly during the slaughter process, where contamination with zoonotic pathogens remains a concern. This study focuses on the potential of organic acids, such as formic and lactic acid, and the oxidizing agent peracetic acid, to decontaminate scalding water and enhance the hygiene of chicken carcasses. We conducted suspension tests introducing various organic loads to mirror the conditions of practical scalding water. Additionally, the surface tests were performed on chicken skin. Both methods were further tested in an experimental slaughtering facility. In suspension tests, the organic acids achieved impressive decontamination, with a 5-log10 reduction of the test organisms Enterococcus hiraeSalmonella Typhimurium and Campylobacter jejuni at minimal concentrations (between 0.04% and 2% for formic acid; between 0.1% and 4.5% for lactic acid). Peracetic acid also effectively sanitized model water and chicken skin, even when used in low concentrations (between 0.001% and 0.1%), both in the laboratory-based testing and in the experimental slaughtering facility. These results suggest that the tested disinfectants can effectively sanitize process water, even under conditions mimicking practical scalding water with organic matter. Peracetic acid, in particular, proved highly effective in improving chicken skin hygiene even at low concentrations.

Research – Antibacterial Activity of Ethanol Extract from Australian Finger Lime

MDPI

Abstract

Australian finger lime (Citrus australasica L.) has become increasingly popular due to its potent antioxidant capacity and health-promoting benefits. This study aimed to determine the chemical composition, antibacterial characteristics, and mechanism of finger lime extract. The finger lime extracts were obtained from the fruit of the Australian finger lime by the ethanol extraction method. The antibacterial activity of the extract was examined by detecting the minimum inhibitory concentration (MIC) for two Gram-positive and four Gram-negative bacterial strains in vitro, as well as by assessing variations in the number of bacteria for Candidatus Liberibacter asiaticus (CLas) in vivo. GC-MS analysis was used to identify the antibacterial compounds of the extract. The antibacterial mechanisms were investigated by assessing cell permeability and membrane integrity, and the bacterial morphology was examined using scanning electron microscopy. The extract demonstrated significant antibacterial activity against Staphylococcus aureusBacillus subtilis, and Gram-negative bacterial species, such as Escherichia coliAgrobacterium tumefaciensXanthomonas campestrisXanthomonas citri, and CLas. Among the six strains evaluated in vitro, B. subtilis showed the highest susceptibility to the antimicrobial effects of finger lime extract. The minimum inhibitory concentration (MIC) of the extract against the tested microorganisms varied between 500 and 1000 μg/mL. In addition, the extract was proven effective in suppressing CLas in vivo, as indicated by the lower CLas titers in the treated leaves compared to the control. A total of 360 compounds, including carbohydrates (31.159%), organic acid (30.909%), alcohols (13.380%), polyphenols (5.660%), esters (3.796%), and alkaloids (0.612%), were identified in the extract. We predicted that the primary bioactive compounds responsible for the antibacterial effects of the extract were quinic acid and other polyphenols, as well as alkaloids. The morphology of the tested microbes was altered and damaged, leading to lysis of the cell wall, cell content leakage, and cell death. Based on the results, ethanol extracts from finger lime may be a fitting substitute for synthetic bactericides in food and plant protection.

Research – Cell-free supernatant of Bacillus tequilensis reduces grey mold/mould caused by Botrytis cinerea of blueberry fruit: Inducing phenylpropanoid pathway metabolism

Frontiers In.org

Botrytis cinerea a blueberry grey mould, is one of the main diseases affecting postharvest storage, causing significant losses. To better control the postharvest gray mould of blueberry, the effects of KXF 6501 fermentation solution (YY) and KXF6501 cell-free supernatant (SQ) on the induction of disease resistance in blueberry fruits were studied using biochemical and transcriptomic analyses. The results showed that YY and SQ controlled the conidial germination and mycelial growth of B. cinerea in vitro. After 3 d of culture, the lesion diameter and incidence of gray mould in blueberry fruits inoculated with YY and SQ were significantly smaller than those in the control group. Transcription spectrum analysis of blueberry peel tissue showed that the YY- and SQ-induced phenylpropane metabolic pathways had more differentially expressed genes (DEGs) than other biological pathways. In addition, biochemical analyses showed that YY and SQ treatments effectively enhanced the activity of enzymes related to the phenylpropane pathway (phenylalanine ammonia-lyase [PAL], cinnamate 4-hydroxylase [C4H], 4-coumarate CoA ligase [4CL], and polyphenol oxidase [PPO]) and stimulated the synthesis of lignin, total phenols, and flavonoids. Compared with the control, the YY and SQ treatments reduced the weight loss rate and better maintained the appearance and nutritional quality of the blueberry fruits. Thus, it can be concluded that Bacillus tequilensis KXF6501 is potentially useful as a suitable bio-control agent in harvested blueberries.

Research – Application of Plant Antimicrobials in the Food Sector: Where Do We Stand?

MDPI

Abstract
The Special Issue “Plant Extracts Used to Control Microbial Growth: Efficacy, Stability and Safety Issues for Food Applications” explored the potential of plant-based extracts as natural antimicrobial agents in the food industry. Its purpose was to address the growing demand for natural, safe, and effective food preservation methods. The contributions highlighted various plant extracts’ antimicrobial efficacy, including phenolic compounds, terpenes, and other bioactive substances. Research papers and one review were submitted from countries, including Spain, Portugal, Italy, Mexico, Turkey, India, USA, Romania, China, and Lithuania, showcasing a diverse international collaboration. Key topics covered in this issue included the chemical characterization of plant extracts, their stability under different processing and storage conditions, and their safety assessments. Advances were reported in using plant extracts to inhibit spoilage microorganisms and foodborne pathogens, enhance food safety, and extend shelf life. The published papers in the Special Issue studied various food types, including yogurt, catfish fillets, edible Mushrooms, red grapes, herring Fillets, and various food types covered in the review. This diversity demonstrates the broad applicability of plant extracts across different food products. Notable findings included the antimicrobial activities of fermented grapevine leaves, grapefruit seed extract, cinnamaldehyde, clove oil, and other plant-based compounds. In conclusion, this Special Issue demonstrated significant progress in applying plant extracts for food preservation, highlighting their potential to contribute to safer and more sustainable food systems worldwide.

Research – Foodborne Pathogenic Bacteria: Prevalence and Control—Volume I

MDPI

1. Introduction

From the farm to the dining table, foodborne pathogenic bacteria can contaminate food at any stage of the food production, processing, delivery, preparation, and consumption chain, posing a critical threat to the safety of food systems worldwide [1]. Staphylococcus aureusEscherichia coliSalmonellaListeria monocytogenesCampylobacter, and Vibrio parahaemolyticus are some of the most common foodborne pathogenic bacteria, and food products contaminated by them traverse intricate global trade networks, posing many disease risks to millions of consumers annually [2]. Foodborne diseases can result from unsafe food storage, processing, preservation, and infected workers, as well as several forms of environmental contamination, including pollution in water, soil, air, infected livestock, and animal feces [3]. Some other factors that increase the incidence of foodborne diseases include the adaptation of pathogens to new environments, the formation of biofilms, the acquisition of virulence factors, and the development of antimicrobial resistance in foodborne pathogenic bacteria [4].
To enhance the safety of our food system, the first step is to know how the food system has been, and could still be, contaminated by common pathogenic bacteria, as well as other emerging and re-emerging pathogenic bacteria. On the other hand, we need to know how these bacteria could survive different storage, processing, and preservation processes in the food system. Biofilm formation and antimicrobial resistance could explain the mechanisms of bacterial survival. However, much is unknown. Once basic information is acquired, we can prevent and control the contamination of foodborne pathogenic bacteria to keep us far away from the pathogens’ attacks.
We are pleased to present this Special Issue on “Foodborne Pathogenic Bacteria: Prevalence and Control”, which contains eleven research articles and two review articles on the detection, prevalence, growth, survival and control. In addition, this Special Issue also covered topics related to rapid detection, persistence in food processing environment, antimicrobial resistance, stress adaptation, antibacterial and antibiofilm mechanisms, etc., as alternative and sustainable innovations to prevent and control the contamination of pathogenic bacteria in the food system. We present a brief overview of each contribution.