Category Archives: Food Technology

Research – Antimicrobial Activity of Essential Oils in Vapor Phase In Vitro and Its Application in Combination with Lactic Acid to Improve Chicken Breast Shelf Life

Posted on November 15, 2023 by | Leave a comment

MDPI

Abstract

The effect of essential oils (EOs) incorporated in their vapor phase combined with lactic acid immersion pretreatment was studied on fresh refrigerated chicken breast shelf life. Among the several EOs assayed, the in vitro results obtained from the vapor diffusion test allowed mustard, oregano, and garlic EOs to be selected due to their higher antimicrobial activity. In addition, it was possible to determine the EO minimum inhibitory concentrations against Pseudomonas aeruginosa and Escherichia coli and to identify EO binary mixtures showing synergistic or additive effects. Based on the obtained results, a ternary mixture constituted by 0.073, 0.292, and 0.146 µL/mL of headspace of mustard, oregano, and garlic, respectively, was proposed for its application to chicken breasts. The ternary mixture inhibitory action was confirmed in vitro against P. aeruginosa and E. coli. Furthermore, the presence of numerous compounds with recognized antimicrobial and antioxidant activity was found in its volatile phase through gas chromatography. When applying an EO mixture in its vapor phase in combination with 1.0% v/v of lactic acid immersion pre-treatment on refrigerated chicken breast, a decrease in mesophilic microorganisms’ growth rate as well as in lipid oxidation was observed. Moreover, in a preliminary sensory test, the treated chicken breast was found to be acceptable to consumers and showed no significant differences compared to untreated chicken. In conclusion, the combined use of lactic acid immersion and EOs in their vapor phase was an effective alternative to increase chicken breast shelf life.

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Posted in E.coli, Food Microbiology Research, Food Technology, Pseudomonas, Pseudomonas aeruginosa, Research

Research – Synergistic Strategies of Heat and Peroxyacetic Acid Disinfection Treatments for Salmonella Control

Posted on November 12, 2023 by | Leave a comment

MDPI

Abstract

The food industry has recognized a pressing need for highly effective disinfection protocols to decrease the risk of pathogen emergence and proliferation in food products. The integration of antimicrobial treatments in food production has occurred as a potential strategy to attain food items of superior quality with respect to microbiological safety and sensory attributes. This study aims to investigate the individual and synergistic effects of heat and peroxyacetic acid on the inactivation of bacterial cells, considering various contact times and environmental conditions. Four Salmonella serotypes, isolated from industrial meat production surfaces, were employed as model organisms. By systematically assessing the impacts of individual factors and synergistic outcomes, the effectiveness of bacterial cell inactivation and the efficiency of heat and peroxyacetic acid could be predicted. To better approximate real-world food processing conditions, this study also incorporated a bovine albumin-rich condition as a simulation of the presence of organic loads in processing steps. The findings revealed the essential need for a synergistic interplay of investigated parameters with the following optimized values: 1.5% concentration of peroxyacetic acid, temperature range of 60–65 °C, and contact time of 3 min for the complete effect regardless of the degree of contamination.

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Posted in Food Microbiology Research, Food Technology, Research, Salmonella, Technology

USA – Sofia Produce, LLC DBA Trufresh Recalls Fresh Cantaloupe Because of Possible Health Risk Due to Salmonella

Posted on November 10, 2023 by | Leave a comment

FDA

Image 1: “Picture of PLU sticker Malichita label”

Summary

Company Announcement Date:
FDA Publish Date:
Product Type:
Food & Beverages
Reason for Announcement:
Potential to be contaminated with Salmonella
Company Name:
Sofia Produce, LLC dba Trufresh
Brand Name:
Malichita
Product Description:
Fresh Cantaloupe

Company Announcement

SOFIA PRODUCE, LLC, of Nogales, Arizona which does business under the name “Trufresh” (“Trufresh”) is recalling all sizes of fresh cantaloupes packaged in cardboard containers labeled with the “Malichita” label, sold under the following sales order numbers between October 16, 2023 and October 23, 2023 because they have the potential to be contaminated with Salmonella:

There have been no reported illnesses associated with the subject cantaloupes, to date.

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Posted in food contamination, food handler, Food Hazard, Food Hygiene, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Testing, Food Pathogen, Food Quality, food recall, Food Safety, Food Safety Alert, Food Safety Management, Food Safety Regulations, Food Technology, Food Testing, Salmonella

Research – Safety Properties of Escherichia coli O157:H7 Specific Bacteriophages: Recent Advances for Food Safety

Posted on November 5, 2023 by | Leave a comment

MDPI

Abstract

Shiga-toxin-producing Escherichia coli (STEC) is typically detected on food products mainly due to cross-contamination with faecal matter. The serotype O157:H7 has been of major public health concern due to the severity of illness caused, prevalence, and management. In the food chain, the main methods of controlling contamination by foodborne pathogens often involve the application of antimicrobial agents, which are now becoming less efficient. There is a growing need for the development of new approaches to combat these pathogens, especially those that harbour antimicrobial resistant and virulent determinants. Strategies to also limit their presence on food contact surfaces and food matrices are needed to prevent their transmission. Recent studies have revealed that bacteriophages are useful non-antibiotic options for biocontrol of E. coli O157:H7 in both animals and humans. Phage biocontrol can significantly reduce E. coli O157:H7, thereby improving food safety. However, before being certified as potential biocontrol agents, the safety of the phage candidates must be resolved to satisfy regulatory standards, particularly regarding phage resistance, antigenic properties, and toxigenic properties. In this review, we provide a general description of the main virulence elements of E. coli O157:H7 and present detailed reports that support the proposals that phages infecting E. coli O157:H7 are potential biocontrol agents. This paper also outlines the mechanism of E. coli O157:H7 resistance to phages and the safety concerns associated with the use of phages as a biocontrol.

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Posted in Bacteriophage, E.coli O157, E.coli O157:H7, Food Microbiology Research, Food Technology, Hurdle Technology, Phage, Research, STEC, STEC E.coli, Technology

Research – Survival of Foodborne Pathogens in Low and Nonalcoholic Craft Beer

Posted on November 4, 2023 by | Leave a comment

Science Direct

Abstract

Breweries and beverage companies have recently been interested in creating innovative beer varieties that deviate from traditional beer styles, with either low-alcohol content <2.5% alcohol by volume (ABV) or the absence of alcohol altogether (<0.5% ABV). Traditional beers (up to 10% ABV) contain numerous intrinsic and extrinsic factors preventing pathogens from proliferation or propagation. Physiochemical properties such as a low pH, presence of ethanol and hop acids, limited oxygen, and specific processing techniques, including wort boiling, pasteurization, filtration, cold storage, and handling, all contribute to microbial stability and safety. The potential change or absence in one or more of these antimicrobial hurdles can render the final product susceptible to pathogen survival and growth. In this study, the effect of pH, storage temperature, and ethanol concentration on the growth or die-off of foodborne pathogens in low and nonalcoholic beers was evaluated. pH and ethanol concentrations were adjusted from their initial values of 3.65 and <0.50% ABV to pHs 4.20, 4.60, and 4.80; and 3.20 ABV, respectively. The samples were inoculated with individual five-strain cocktails of E. coli O157:H7, S. enterica, and L. monocytogenes, then stored at two different temperatures (4 and 14°C) for 63 days. Microbial enumeration was performed using selective agar with incubation at 35°C. Results showed that nonalcoholic beers allowed for pathogen growth and survival, as opposed to the low-alcoholic ones. E. coli O157:H7 and S. enterica grew approximately 2.00 log  at 14°C, but no growth was observed at 4°C. L. monocytogenes was more susceptible and fell at, or below, the detection limit rapidly in all the conditions tested. The results show that storage temperature is critical in preventing the growth of pathogens. pH did not appear to have a significant effect on the survival of pathogens (p < 0.05). This challenge study demonstrates the need for beverage manufacturers to prioritize and maintain food safety plans along with practices specific to low- and nonalcoholic beer manufacturers.

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Posted in antimicrobial resistance, Antimicrobials, E.coli O157, E.coli O157:H7, Food Microbiology Research, Food Technology, Listeria, Listeria monocytogenes, Research, Salmonella, Technology

Research – Inactivation Kinetics of Foodborne Pathogens in Carrot Juice by High-Pressure Processing

Posted on November 1, 2023 by | Leave a comment

MDPI

Abstract

In this study, Salmonella Typhimurium, Escherichia coli, and Listeria monocytogenes were separately inoculated in sterilized carrot juice and subjected to various types of high-pressure processing (HPP) at 200–600 MPa for 0.1–15 min to observe the effects of HPP on the inactivation kinetics of foodborne pathogens in carrot juice. The first-order model fits the destruction kinetics of high pressure on foodborne pathogens during the pressure hold period. An increase in pressure from 200 to 600 MPa decreased the decimal reduction time (D values) of S. Typhimurium, E. coli, and L. monocytogenes. Under pressure ≥ 400 MPa, the D values of E. coli were significantly higher than those of S. Typhimurium and L. monocytogenes, indicating that E. coli had greater resistance to high pressures than the others. The Zp values (the pressure range that causes the D values to change by 90%) of E. coli, S. Typhimurium, and L. monocytogenes were 195, 175, and 170 MPa, respectively. These results indicated that L. monocytogenes and E. coli were the most and least sensitive, respectively, to pressure changes. Additionally, the three bacteria were separately inoculated into thermal-sterilized carrot juice and subjected to 200–600 MPa HPP for 3 min. The treated carrot juices were stored at 4 °C for 27 d. Following S. Typhimurium and E. coli inoculation, the bacterial counts of the control and 200 MPa treatments remained the same during the storage duration. However, they decreased for the 300 and 400 MPa treatment groups with increasing storage duration. During the storage period, no bacterial growth was observed in the 500 and 600 MPa treatments. However, the bacterial number for the control and pressure treatment groups increased with prolonged storage duration following inoculation with L. monocytogenes. Therefore, following HPP, residual L. monocytogenes continued growing stably at low temperatures. Overall, HPP could inhibit and delay the growth of S. Typhimurium and E. coli in carrot juice during cold storage, but it was ineffective at inhibiting the growth of L. monocytogenes. There was a risk of foodborne illness despite the low-temperature storage of juice. The innovation of this preliminary study is to find the impact of high pressure on the inactivate kinetics of three food pathogens in carrot juice and its practical application in simulated contaminated juice.

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Posted in E.coli, Food Microbiology Research, Food Pathogen, Food Technology, HPP, Hurdle Technology, Listeria, Listeria monocytogenes, Pathogen, pathogenic, Research, Salmonella, Technology

Research – Role of Bacillus cereus biofilm formation behavior in virulence and pathogenic characteristics

Posted on October 29, 2023 by | Leave a comment

Wiley Online

Abstract

This study aimed to examine the potential link between Bacillus cereus biofilm formation, virulence, and pathogenicity. The biofilm formation abilities of nine B. cereus strains isolated from food and two reference strains (ATCC 10876 and ATCC 25621) were measured using a crystal violet assay. Among the tested strains, three strains (GIHE 617-5, GIHE 86-09, and GIHE 728-17) and both reference strains were capable of biofilm formation. A positive correlation was obtained for higher cell surface hydrophobicity and increased biofilm formation. In contrast, HPLC analysis for elevated autoinducer-2 (Al-2) production revealed a negative impact on biofilm formation. PCR data indicated that all tested strains were capable of producing common B. cereus enterotoxins, including Hbl—A, C, and D, CytK, Nhe—B and C, EntFM, and BceT, but were negative for production of the emetic toxin cereulide and the pore-forming toxin Hly II. Meanwhile, RT-PCR data revealed a close correlation between high biofilm formation and the upregulation of several tested virulence genes for selected strains. However, elevated upregulation of virulence genes was not consistent in all of the higher biofilm-forming strains. Cytotoxicity analysis revealed higher virulence characteristics compared to those of low biofilm-forming strains.

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Posted in Bacillus, Bacillus cereus, Biofilm, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Technology, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, Research, Technology

Research – High-Pressure Processing—Impacts on the Virulence and Antibiotic Resistance of Listeria monocytogenes Isolated from Food and Food Processing Environments

Posted on October 29, 2023 by | Leave a comment

MDPI

Abstract

High-pressure processing (HPP) is one of the non-thermal methods of food preservation considered to be safe but may cause an increase/decrease in virulence potential and antibiotic resistance. The aim of the present study was to evaluate the survival of L. monocytogenes isolates after high-pressure processing (200 and 400 MPa for 5 min) and to determine changes in phenotypic and genotypic antibiotic resistance and virulence after this treatment. The 400 MPa treatment was shown to be effective in reducing pathogens to safe levels; however, the potential for cell recovery during storage was observed. In addition, studies on changes in virulence indicated possibilities related to a decrease in actA gene expression, overexpression of the hly and osfX gene, and an increase in biofilm-forming ability. The studies on changes in antibiotic resistance of isolates showed that all isolates showing initial susceptibility to lincomycin, fosfomycin, trimethoprim/sulfamethoxazole, and tetracycline became resistant to these antibiotics, which was associated with an increase in the values of minimum inhibitory concentrations. An increase in the expression of antibiotic resistance genes (mainly tetA_1, tetA_3, tetC) was also observed (mainly after the application of 200 MPa pressure), which was isolate dependent. However, it is noteworthy that the induced changes were permanent, i.e., they persisted even after the restoration of optimal environmental conditions. The results presented in our work indicate that the stress occurring during HPP can affect both phenotypic and genotypic changes in the virulence and antibiotic resistance potential of pathogens isolated from food and food processing environments. The potential associated with cell recovery and persistence of changes may influence the spread of virulent isolates of pathogens with increased antibiotic resistance in the food and food processing environment.

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Posted in Food Microbiology Research, Food Technology, Food Testing, HPP, Listeria, Listeria monocytogenes, Research

Research – The Rapid Detection of Salmonella enterica, Listeria monocytogenes, and Staphylococcus aureus via Polymerase Chain Reaction Combined with Magnetic Beads and Capillary Electrophoresis

Posted on October 28, 2023 by | Leave a comment

MDPI

Abstract

Food safety concerns regarding foodborne pathogen contamination have gained global attention due to its significant implications. In this study, we developed a detection system utilizing a PCR array combined with an automated magnetic bead-based system and CE technology to enable the detection of three foodborne pathogens, namely Salmonella enterica, Listeria monocytogenes, and Staphylococcus aureus. The results showed that our developed method could detect these pathogens at concentrations as low as 7.3 × 101, 6.7 × 102, and 6.9 × 102 cfu/mL, respectively, in the broth samples. In chicken samples, the limit of detection for these pathogens was 3.1 × 104, 3.5 × 103, and 3.9 × 102 cfu/g, respectively. The detection of these pathogens was accomplished without the necessity for sample enrichment, and the entire protocols, from sample preparation to amplicon analysis, were completed in approximately 3.5 h. Regarding the impact of the extraction method on detection capability, our study observed that an automated DNA extraction system based on the magnetic bead method demonstrated a 10-fold improvement or, at the very least, yielded similar results compared to the column-based method. These findings demonstrated that our developed model is effective in detecting low levels of these pathogens in the samples analyzed in this study. The PCR-CE method developed in this study may help monitor food safety in the future. It may also be extended to identify other foodborne pathogens across a wide range of food samples.

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Posted in Food Microbiology Research, Food Technology, Research, Salmonella, Technology

Research – Pathogen that plagues food processing plants eradicated by blue light – Listeria monocytogenes

Posted on October 22, 2023 by | Leave a comment

News Wise

Newswise — Washington, D.C. – Blue light kills both dried cells and biofilms of the pathogen Listeria monocytogenes, a frequent contaminant of food processing facilities. Demise of L. monocytogenes occurred quickest when cells or biofilms were placed on polystyrene, a widely used, transparent form of plastic. The research is published in Applied and Environmental Microbiology, a journal of the American Society for Microbiology.

“These results contribute to advancing our understanding of the potential of blue light to treat inert surfaces contaminated with L. monocytogenes,” said corresponding author Francisco Diez-Gonzalez, Ph.D., Director and Professor, Center for Food Safety, University of Georgia. Although biofilms of pathogens are generally powerfully resistant to being exterminated, the results suggest that blue light could effectively destroy L. monocytogenes.

In the study, the investigators deposited liquid suspensions of mixtures of 5 strains of L. monocytogenes on small, sterile rectangular plates made of 6 different materials, including polystyrene, stainless steel and silicone rubber, which were then allowed to dry. The investigators also used similar plates to grow biofilms, which they also allowed to dry.

Then, they shined blue light onto the biofilms and onto the dried suspensions of cells on the plates to determine the most effective combinations of doses and wavelengths, as well as the most effective surfaces on which to extirpate the pathogens.

“The application of blue light for controlling microbial contamination has the potential to offer an additional technology that could complement existing methods for disinfecting surfaces in contact with foods,” said Diez-Gonzalez, noting that blue light has been used for disinfection in hospitals. As compared to ultraviolet light, blue light offers reduced risk for the user, he said.

A post-doc in Diez-Gonzalez’ laboratory, Fereidoun Forghani, Ph.D., kick-started the investigation when—searching for new ideas—he came across the use of blue light as a potential antimicrobial intervention to sanitize surfaces. Forghani built some blue light prototypes and produced the first preliminary results treating pure cultures of Listeria.

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Posted in Blue Light, Decontamination Microbial, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Technology, Listeria, Listeria monocytogenes, microbial contamination, Microbial growth, Microbiological Risk Assessment, Microbiology, Microbiology Investigations, Microbiology Risk, Research, Technology