Category Archives: Technology

Research – Effect of Treatment with Heated Scallop Shell Powder on the Inactivation of Naturally Existing Bacteria and Listeria monocytogenes Inoculated on Chicken Meat

Posted on January 28, 2024 by | Leave a comment

MDPI

Abstract

This study investigated the efficacy of heated scallop shell powder (HSSP) treatment in preserving chicken thigh meat. Chicken thigh meat was treated with HSSP slurry (1% and 5%) for 60 min, and the variation in aerobic bacteria and coliform populations was assessed during refrigerated storage (10 °C). There was a substantial increase in aerobic bacteria, reaching nearly 7 log10 colony forming unit (CFU)/g following 7 days of refrigeration, in the untreated chicken meat. Conversely, the aerobic bacterial population of the HSSP-treated chicken was <5 log10 CFU/g. Coliform growth in the untreated chicken reached over 5 log10 CFU/g following 7 days. In contrast, the coliform population of the HSSP-treated chicken did not reach 5 log10 CFU/g at 1% HSSP concentration; it was suppressed to <4 log10 CFU/g at 5% concentration. Listeria monocytogenes, which can grow at low temperatures, was inoculated into the chicken meat (5 log10 CFU/g) treated with alcohol, which was followed by HSSP. In the untreated chicken, L. monocytogenes increased to 9 log10 CFU/g even when refrigerated for 7 days. However, in the chicken treated with 5% HSSP, L. monocytogenes was suppressed to approximately 3 log10 CFU/g. These findings reveal that HSSP treatment is an effective method for disinfecting meat, inhibiting bacterial growth, and enhancing preservation.

Leave a comment

Posted in Coliforms, Food Microbiology Research, Food Technology, Heated scallop shell powder (HSSP), Listeria, Listeria monocytogenes, Research, Technology

Research – Application of Ultrasound Treatments in the Processing and Production of High-Quality and Safe-to-Drink Kiwi Juice

Posted on January 27, 2024 by | Leave a comment

MDPI

Abstract

This study explores the potential of thermosonication as an alternative to traditional heat treatments, such as pasteurization, in the processing of fruit juices. Conventional methods often lead to undesirable quality changes in fruit juices, whereas thermosonication offers promising results regarding microbial inactivation and quality preservation. This work focused on the inactivation kinetics of Listeria innocua 2030c, a surrogate for pathogenic L. monocytogenes, in kiwifruit juice using thermosonication at 45 °C, 50 °C, and 55 °C. These treatments were compared with equivalent heat treatments. Quality attributes of the juice were also evaluated to assess process efficiency. Survival data of L. innocua were fitted with the Weibull model, estimating first decimal reduction times (δ) and shape parameters (n). The results reveal temperature and process dependencies on δ, while n remains mostly temperature and treatment independent. Thermosonication outperforms heat treatment, achieving higher L. innocua reductions while retaining quality attributes like pH, soluble solid content, and total phenolics and chlorophylls. Thermosonication at 55 °C stands out, providing a 6.2-log-cycle reduction in just 3 min with superior quality retention. These findings highlight the synergistic effect of temperature and ultrasound, making mild heat processes feasible while enhancing product quality. Thermosonication, particularly at 55 °C, emerges as an effective alternative to traditional thermal treatments for fruit juices, offering improved microbial safety without compromising product quality.

Leave a comment

Posted in Food Microbiology Research, Food Pathogen, Food Technology, Listeria, Listeria innocua, Listeria monocytogenes, Pathogen, pathogenic, Research, Technology, Thermosonication

Research – Effectiveness of Ultra-High Irradiance Blue-Light-Emitting Diodes to Control Salmonella Contamination Adhered to Dry Stainless Steel Surfaces

Posted on January 7, 2024 by | Leave a comment

MDPI

Controlling Salmonella contamination in dry food processing environments represents a significant challenge due to their tolerance to desiccation stress and enhanced thermal resistance. Blue light is emerging as a safer alternative to UV irradiation for surface decontamination. In the present study, the antimicrobial efficacy of ultra-high irradiance (UHI) blue light, generated by light-emitting diodes (LEDs) at wavelengths of 405 nm (841.6 mW/cm2) and 460 nm (614.9 mW/cm2), was evaluated against a five-serovar cocktail of Salmonella enterica dry cells on clean and soiled stainless steel (SS) surfaces. Inoculated coupons were subjected to blue light irradiation treatments at equivalent energy doses ranging from 221 to 1106 J/cm2. Wheat flour was used as a model food soil system. To determine the bactericidal mechanisms of blue light, the intracellular concentration of reactive oxygen species (ROS) in Salmonella cells and the temperature changes on SS surfaces were also measured. The treatment energy dose had a significant effect on Salmonella inactivation levels. On clean SS surfaces, the reduction in Salmonella counts ranged from 0.8 to 7.4 log CFU/cm2, while, on soiled coupons, the inactivation levels varied from 1.2 to 4.2 log CFU/cm2. Blue LED treatments triggered a significant generation of ROS within Salmonella cells, as well as a substantial temperature increase in SS surfaces. However, in the presence of organic matter, the oxidative stress in Salmonella cells declined significantly, and treatments with higher energy doses (>700 J/cm2) were required to uphold the antimicrobial effectiveness observed on clean SS. The mechanism of the bactericidal effect of UHI blue LED treatments is likely to be a combination of photothermal and photochemical effects. These results indicate that LEDs emitting UHI blue light could represent a novel cost- and time-effective alternative for controlling microbial contamination in dry food processing environments.

Leave a comment

Posted in Blue Light, Food Microbiology Research, Food Technology, Research, Salmonella, Technology, UV Microbiology, UV-C

Research – Positive and negative aspects of bacteriophages and their immense role in the food chain

Posted on January 6, 2024 by | Leave a comment

Nature

Abstract

Bacteriophages infect and replicate inside a bacterial host as well as serve as natural bio-control agents. Phages were once viewed as nuisances that caused fermentation failures with cheese-making and other industrial processes, which lead to economic losses, but phages are now increasingly being observed as being promising antimicrobials that can fight against spoilage and pathogenic bacteria. Pathogen-free meals that fulfil industry requirements without synthetic additives are always in demand in the food sector. This study introduces the readers to the history, sources, and biology of bacteriophages, which include their host ranges, absorption mechanisms, lytic profiles, lysogenic profiles, and the influence of external factors on the growth of phages. Phages and their derivatives have emerged as antimicrobial agents, biodetectors, and biofilm controllers, which have been comprehensively discussed in addition to their potential applications in the food and gastrointestinal tract, and they are a feasible and safe option for preventing, treating, and/or eradicating contaminants in various foods and food processing environments. Furthermore, phages and phage-derived lytic proteins can be considered potential antimicrobials in the traditional farm-to-fork context, which include phage-based mixtures and commercially available phage products. This paper concludes with some potential safety concerns that need to be addressed to enable bacteriophage use efficiently.

Leave a comment

Posted in Bacteriophage, Food Microbiology Research, Food Technology, Phage, Research, Technology

Research – Evaluation of the Effectiveness of Aeration and Chlorination during Washing to Reduce E. coli O157:H7, Salmonella enterica, and L. innocua on Cucumbers and Bell Peppers

Posted on January 6, 2024 by | Leave a comment

MDPI

Abstract

The attachment strength of bacteria to surfaces can affect the efficacy of sanitizers during washing. This study aimed to determine the effectiveness of chlorination and aeration in the removal of pathogens from the surface of produce. Cucumbers and bell peppers were inoculated with Listeria innocua, Escherichia coli O157:H7, or Salmonella enterica; afterwards, the produce was washed with or without chlorinated water (100 ppm) for 3 min in combination with or without aeration. Cucumbers washed with chlorinated water, with or without aeration, presented significant reductions of L. innocua (3.65 log CFU/cm2 and 1.13 log CFU/cm2, respectively) (p < 0.05). Similarly, bell peppers washed in chlorinated water with aeration (1.91 log CFU/g) and without aeration (2.49 log CFU/g) presented significant reductions of L. innocua. A significant reduction of L. innocua was observed on bell peppers washed with non-chlorinated water with aeration (2.49 log CFU/g) (p < 0.05). Non-chlorinated water was also effective in significantly reducing the level of Salmonella enterica (p < 0.05) on cucumbers and bell peppers. Washing with chlorinated water with aeration reduced Salmonella enterica levels from 4.45 log CFU/cm2 on cucumbers to below the detectable limit (0.16 log CFU/cm2). The highest reduction of Salmonella enterica from bell peppers occurred after washing with chlorinated water with aeration (2.48 log CFU/g). E. coli O157:H7, L. innocua, and Salmonella enterica levels present in non-chlorinated water after washing contaminated produce with or without aeration were significantly greater than those in chlorinated water (p < 0.05). After treatment, the population levels of all pathogens in chlorinated water with or without aeration were below the detectable limit for bell peppers (<1.10 log CFU/mL) and cucumbers (<1.20 log CFU/mL). Using chlorine in combination with forced aeration during washing minimizes cross-contamination of bacterial pathogens.

Leave a comment

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

Research – ‘UK should break licensing impasse and maximise the potential of phages’

Posted on January 4, 2024 by | Leave a comment

The Microbiologist

In a major new report the UK’s Science, Innovation & Technology Committee has called for steps to develop the potential of bacteria-killing viruses – called bacteriophages or phages for short – that can provide an alternative to antibiotics that are attracting growing resistance.

Leave a comment

Posted in Bacteriophage, Food Microbiology Research, Food Technology, Phage, Research, Technology

Research – Association between the Presence of Resistance Genes and Sanitiser Resistance of Listeria monocytogenes Isolates Recovered from Different Food-Processing Facilities

Posted on December 31, 2023 by | Leave a comment

MDPI

Abstract

Sanitisers are widely used in cleaning food-processing facilities, but their continued use may cause an increased resistance of pathogenic bacteria. Several genes have been attributed to the increased sanitiser resistance ability of L. monocytogenes. This study determined the presence of sanitiser resistance genes in Irish-sourced L. monocytogenes isolates and explored the association with phenotypic sanitiser resistance. The presence of three genes associated with sanitiser resistance and a three-gene cassette (mdrL, qacH, emrE, bcrABC) were determined in 150 L. monocytogenes isolates collected from Irish food-processing facilities. A total of 23 isolates contained bcrABC, 42 isolates contained qacH, one isolate contained emrE, and all isolates contained mdrL. Additionally, 47 isolates were selected and grouped according to the number and type of resistance genes, and the minimal inhibitory concentration (MIC) of these isolates for benzalkonium chloride (BAC) was determined experimentally using the broth microdilution method. The BAC resistance of the strain carrying the bcrABC gene cassette was significantly higher than that of strains lacking the gene cassette, and the BAC resistance of the strain carrying the qacH gene was significantly higher than that of strains lacking the qacH gene (p < 0.05). Isolates harbouring both the qacH and bcrABC genes did not show higher BAC resistance. With respect to environmental factors, there was no significant difference in MIC values for isolates recovered from different processing facilities. In summary, this investigation highlights the prevalence of specific sanitiser resistance genes in L. monocytogenes isolates from Irish food-processing settings. While certain genes correlated with increased resistance to benzalkonium chloride, the combination of multiple genes did not necessarily amplify this resistance.

Leave a comment

Posted in Disinfection Resistance, Food Microbiology Research, Food Technology, Listeria, Listeria monocytogenes, Research, Technology

Research -High technology is the key to detecting foodborne outbreaks over space and time

Posted on December 12, 2023 by | Leave a comment

Lex Blog

Most people think of foodborne illness outbreaks as spanning a few days or weeks. But, with current technology, disease detectives can find patients of a single outbreak spread across several years and multiple states.

That is the case with an ongoing outbreak of Listeria illnesses linked to fresh peaches that began in 2018. So far, 11 patients have been identified, most recently found in August this year. One of the patients died. Recent recalls of peaches, nectarines, and plums have been initiated while public health officials continue investigating the outbreak.

The links between people sickened in the outbreak this year and the initial patient in 2018 were made possible using whole genome sequencing (WGS). Whole genome sequencing has been likened to fingerprinting used in criminal investigations, but WGS allows the Centers for Disease Control and Prevention to look at millions of pieces of data.

“WGS examines more than 4.5 million ‘letters’ of the genetic code in disease-causing bacteria such as Salmonella. Bacteria closely related by WGS are more likely to have originated from the same source than more distantly related bacteria,” said John Besser, who retired in 2019 as Deputy Chief of the Enteric Diseases Laboratory Branch at the CDC. He continues to work on CDC-related projects through the Association of Public Health Laboratories.

“Ill persons in a WGS cluster will likely have shared exposure, such as a contaminated food product. By focusing on WGS clusters, investigators can detect outbreaks when they are small, even if cases are dispersed over multiple states or widely separated in time.”

Leave a comment

Posted in CDC, food bourne outbreak, Food Illness, Food Microbiology Research, Food Technology, Foodborne Illness, foodborne outbreak, foodbourne outbreak, Illness, outbreak, Research, Technology, WGS

Research – Lightning sparks scientists’ design of ultraviolet-C device for food sanitization

Posted on December 10, 2023 by | Leave a comment

News Illinois

Scientists at the University of Illinois Urbana-Champaign have developed a portable, self-powered ultraviolet-C device called the Tribo-sanitizer that can inactivate two of the bacteria responsible for many foodborne illnesses and deaths.

Leave a comment

Posted in Food Microbiology Research, Food Pathogen, Food Technology, Pathogen, pathogenic, Research, Technology, UV Microbiology, UV-C

Research – Pilot Scale Assessment of High-Pressure Processing (HPP) to Enhance Microbiological Quality and Shelf Life of Fresh Ready-to-Eat (RTE) Blue Crab Meat

Posted on December 9, 2023 by | Leave a comment

MDPI

Abstract

Blue crab (Callinectes sapidus) is a highly valuable wild fishery species of crab native to the waters of the western Atlantic Ocean and the Gulf of Mexico. The annual commercial production of live blue crabs is approximately 50,000 metric tons with a dockside value of USD 200 million. Presently the US blue crab processing industry sells crab meat in three basic forms: fresh crab meat, pasteurized crab meat, and frozen crab meat. By far “Fresh” is the most desirable form of crab meat. However, fresh crab meat has a limited shelf life. This study evaluated the effects of high-pressure processing (HPP) on enhancing the microbiological quality and shelf life of blue crab meat. Live blue crabs were pressure-cooked in a retort (≥115 °C for 4–6 min). The crab meat was handpicked, packed in plastic containers with seals, subjected to HPP treatment, and stored at 4 °C. Container integrity and water leakage issues were examined by observation in addition to weight comparison before and after HPP treatment; the shelf life of crab meat with and without HPP treatments was examined via microbiological tests and sensory evaluations. Results show that polypropylene containers sealed with 10K OTR (oxygen transmission rate) film could withstand high pressure without water leakage issues; HPP treatment at 600 MPa for 3 min could extend the shelf life of fresh, cooked, and handpicked crab meat from 6 days to 18 days based on the strictest APC (aerobic plate account) limit (APC ≤ 100,000 CFU/g). The sensory quality of the HPP-treated crab meat was well accepted throughout the 3-week storage period. The results support the use of HPP as an effective non-thermal processing technology to enhance the microbiological quality and extend the shelf life of fresh RTE blue crab meat.

Leave a comment

Posted in Food Microbiology Research, HPP, Research, Technology