Chicken fillets subjected to UV-C and pulsed UV light: Reduction of pathogenic and spoilage bacteria, and changes in sensory quality

Combined treatment of pulsed light and nisin-organic acid based antimicrobial wash for inactivation of Escherichia coli O157:H7 in Romaine lettuce, reduction of microbial loads, and retention of quality

Microbial safety of fresh produce continues to be a major concern. Novel antimicrobial methods are needed to minimize the risk of contamination. This study investigated the antimicrobial efficacy of pulsed light (PL), a novel nisin-organic acid based antimicrobial wash (AW) and the synergy thereof in inactivating E. coli O157:H7 on Romaine lettuce. Treatment effects on background microbiota and produce quality during storage at 4 °C for 7 days was also investigated. A bacterial cocktail containing three outbreak strains of E. coli O157:H7 was used as inoculum. Lettuce leaves were spot inoculated on the surface before treating with PL (1-60 s), AW (2 min) or combinations of PL with AW. PL treatment for 10 s, equivalent to fluence dose of 10.5 J/cm2, was optimal and resulted in 2.3 log CFU/g reduction of E. coli O157:H7, while a 2 min AW treatment, provided a comparable pathogen reduction of 2.2 log CFU/g. Two possible treatment sequences of PL and AW combinations were investigated. For PL-AW combination, inoculated lettuce leaves were initially exposed to optimum PL dose followed by 2 min AW treatment, whereas for AW-PL combination, inoculated lettuce were subjected to 2 min AW treatment prior to 10 s PL treatment. Both combination treatments (PL-AW and AW-PL) resulted in synergistic inactivation as E. coli cells were not detectable after treatment, indicating >5 log pathogen reductions. Combination treatments significantly (P < 0.05) reduced spoilage microbial populations on Romaine lettuce and also hindered their growth in storage for 7 days. The firmness and visual quality appearance of lettuce were not significantly (P > 0.05) influenced due to combination treatments. Overall, the results reveal that PL and AW combination treatments can be implemented as a novel approach to enhance microbial safety, quality and shelf life of Romaine lettuce.

Nonthermal Sterilization of Animal-based Foods by Intense Pulsed Light Treatment

The consumption of meat has been increasing, leading to a dynamic meat and meat processing industry. To maintain the quality and safety of meat products, various technologies have been explored, including intense pulsed light (IPL) technology. Several factors affect the inactivation of microorganisms by IPL treatment, including light intensity (fluence), treatment duration, pulse frequency, and the distance between the lamp and the samples. Meat products have been studied for IPL treatment, resulting in microbial reductions of approximately 0.4-2.4 Log. There are also impacts on color, sensory attributes, and physico-chemical quality, depending on treatment conditions. Processed meat products like sausages and ham have shown microbial reductions of around 0.1-4 Log with IPL treatment. IPL treatment has minimal impact on color and lipid oxidation in these products. Egg products and dairy items can also benefit from IPL treatment, achieving microbial reductions of around 1-7.8 Log. The effect on product quality varies depending on the treatment conditions. IPL technology has shown promise in enhancing the safety and quality of various food products, including meat, processed meat, egg products, and dairy items. However, the research results on animal-based food are not diverse and fragmentary, this study discusses the future research direction and industrial application through a review of these researches.

Radical species generating technologies for decontamination of Listeria species in food: a recent review report

Foodborne illnesses occur due to the contamination of fresh, frozen, or processed food products by some pathogens. Among several pathogens responsible for the illnesses, Listeria monocytogenes is one of the lethal bacteria that endangers public health. Several preexisting and novel technologies, especially non-thermal technologies are being studied for their antimicrobial effects, particularly toward L. monocytogenes. Some noteworthy emerging technologies include ultraviolet (UV) or light-emitting diode (LED), pulsed light, cold plasma, and ozonation. These technologies are gaining popularity since no heat is employed and undesirable deterioration of food quality, especially texture, and taste is devoided. This review aims to summarize the most recent advances in non-thermal processing technologies and their effect on inactivating L. monocytogenes in food products and on sanitizing packaging materials. These technologies use varying mechanisms, such as photoinactivation, photosensitization, disruption of bacterial membrane and cytoplasm, etc. This review can help food processing industries select the appropriate processing techniques for optimal benefits, in which the structural integrity of food can be preserved while simultaneously destroying L. monocytogenes present in foods. To eliminate Listeria spp., different technologies possess varying mechanisms such as rupturing the cell wall, formation of pyrimidine dimers in the DNA through photochemical effect, excitation of endogenous porphyrins by photosensitizers, generating reactive species, causing leakage of cellular contents and oxidizing proteins and lipids. These technologies provide an alternative to heat-based sterilization technologies and further development is still required to minimize the drawbacks associated with some technologies.

Comparison of the impact of UV-light emitting diode and UV lamp at pilot-plant scale level on quality parameters and consumer perception of fresh chicken meat

The present study compared the impact of two UV light devices: conventional UV lamp and UV-LED on the colour, pH, lipid and protein oxidation of fresh chicken breast meat aerobically stored at 4 °C for 10 days. Lipid oxidation was the most impacted quality attribute in UV lamp treated meat, unlike UV-LED that showed no effect compared to non-treated meat. Slight changes were observed in colour, pH and protein oxidation of chicken samples subjected to UV lamp and UV-LED. To evaluate these changes from a consumer perspective, the different treatment samples were stored at 4 °C for 3 days and colour likeness, odour likeness and overall appearance were assessed by consumer sensory analysis. However, alterations in quality parameters of chicken meat caused by UV light did not decrease overall acceptance in the sensory analysis. UV-LED was the preferred chicken meat by the participants, even compared to non-treated meat.

Principles and Applications of Non-Thermal Technologies for Meat Decontamination

Meat contains high-value protein compounds that might degrade as a result of oxidation and microbial contamination. Additionally, various pathogenic and spoilage microorganisms can grow in meat. Moreover, contamination with pathogenic microorganisms above the infectious dose has caused foodborne illness outbreaks. To decrease the microbial population, traditional meat preservation methods such as thermal treatment and chemical disinfectants are used, but it may have limitations for the maintenance of meat quality or the consumers acceptance. Thus, non-thermal technologies (e.g., high-pressure processing, pulsed electric field, non-thermal plasma, pulsed light, supercritical carbon dioxide technology, ozone, irradiation, ultraviolet light, and ultrasound) have emerged to improve the shelf life and meat safety. Non-thermal technologies are becoming increasingly important because of their advantages in maintaining low temperature, meat nutrition, and short processing time. Especially, pulsed light and pulsed electric field treatment induce few sensory and physiological changes in high fat and protein meat products, making them suitable for the application. Many research results showed that these non-thermal technologies may keep meat fresh and maintain heat-sensitive elements in meat products.

The Application of Ultraviolet Treatment to Prolong the Shelf Life of Chilled Beef

This study simulated the storage conditions of chilled beef at retail or at home, and the sterilization and preservation effects of short-time ultraviolet irradiation were studied. The conditions of different irradiation distances (6 cm, 9 cm, and 12 cm) and irradiation times (6 s, 10 s, and 14 s) of ultraviolet (UV) sterilization in chilled beef were optimized, so as to maximally reduce the initial bacterial count, but not affect the quality of the chilled beef. Then, the preservation effect on the chilled beef after the optimized UV sterilization treatment during 0 ± 0.2 °C storage was investigated. The results showed that UV irradiation with parameters of 6 cm and 14 s formed the optimal UV sterilization conditions for the chilled beef, maximally reducing the number of microorganisms by 0.8 log CFU/g without affecting lipid oxidation or color change. The 6 cm and 14 s UV sterilization treatment of the chilled beef was able to reduce the initial microbial count, control the bacterial growth, and delay the increase in the TVB-N values during storage. Compared with the control group, the total bacterial count decreased by 0.56-1.51 log CFU/g and the TVB-N value decreased by 0.20-5.02 mg N/100 g in the UV-treated group. It was found that the TBARS value of the UV treatment group increased during late storage; on days 9-15 of storage, the TBARS values of the treatment group were 0.063-0.12 mg MDA/kg higher than those of the control group. However, UV treatment had no adverse impact on the pH, color, or sensory quality of chilled beef. These results prove that UV treatment can effectively reduce the microbial count on the surface of beef and improve its microbial safety, thus maintaining the quality of beef and prolonging its shelf life. This study could provide a theoretical basis for the preservation technology of chilled beef in small-space storage equipment.

Advances in enteropathogen control throughout the meat chicken production chain

Enteropathogens, namely Salmonella and Campylobacter, are a concern in global public health and have been attributed in numerous risk assessments to a poultry source. During the last decade, a large body of research addressing this problem has been published. The literature reviewed contains review articles on certain aspects of poultry production chain; however, in the past decade there has not been a review on the entire chain-farm to fork-of poultry production. For this review, a pool of 514 articles were selected for relevance via a systematic screening process (from >7500 original search articles). These studies identified a diversity of management and intervention strategies for the elimination or reduction of enteropathogens in poultry production. Many studies were laboratory or limited field trials with implementation in true commercial operations being problematic. Entities considering using commercial antienteropathogen products and interventions are advised to perform an internal validation and fit-for-purpose trial as Salmonella and Campylobacter serovars and biovars may have regional diversity. Future research should focus on nonchemical application within the processing plant and how a combination of synergisticinterventions through the production chain may contribute to reducing the overall carcass burden of enteropathogens, coupled with increased consumer education on safe handling and cooking of poultry.

The potential of UVC decontamination to prolong shelf-life of par-baked bread

The effect of UVC (254 nm) treatment on the mould-free shelf-life of par-baked wholemeal, rye and six-grain bread was examined. Currently, these breads are par-baked, wrapped in high-density polyethylene (HDPE)-foil and transported or stored at room temperature for a couple of days before being full-baked and sold/consumed. Generally, after five days, these breads show signs of mould spoilage. A shelf-life increase in one or more days would already offer immense economical and logistic benefits for the baker or retailer. In this study, the parameters fluence rate (irradiation intensity), fluence (UV dose), distance to the UV-lamp (DTL) and number of layers of a common wrapping HDPE-foil (20 µm) were diversified. The breads were subjected to a UVC treatment (0-2502 mJ/cm²), packed and stored at room temperature for a period of 15 days (21.5 ± 0.8°C). Similar as for the breads, agar plates with mould spores of Aspergillus niger, Aspergillus montevidensis and Penicillium roqueforti were UVC treated (0-1664 mJ/cm²) and checked daily for visible mould growth during 15 days (25°C). Aspergillus niger showed the strongest resistance towards UVC, a fluence of 800 mJ/cm² was needed to inhibit growth during 15 days of storage, whereas for P. roqueforti and A. montevidensis, respectively, UV levels of 291 and 133 mJ/cm² were found sufficient. Furthermore, the shelf-life of wholemeal, rye and six-grain bread can be prolonged from 5 to 6, 8 and 9 days, respectively, using 2502 mJ/cm². The effect of higher UVC dosage on shelf-life reached a maximal level and was strongly impacted by the wide spread on data of mould-free shelf-life. The main factors influencing the potential of UV decontamination were the rough bread surface, differences in DTL, the possibility of post-contamination and UV permeability of packaging materials.

Effects of UV-C Irradiation and Vacuum Sealing on the Shelf-Life of Beef, Chicken and Salmon Fillets

One-third of the world's food supply is lost, with meat being a major contributor to this loss. Globally, around 23% of all meat and 35% of all seafood products are lost or wasted. Meats and seafood products are susceptible to microbial spoilage during processing, storage, and distribution, where microbial contamination causes significant losses throughout the supply chain. This study examined the efficacy of UV-C irradiation and vacuum-sealing in preventing microbiological deterioration in beef, chicken, and salmon fillets. The samples were sterilized using a constant UV-C irradiation dose of 360 J/m² and stored under a reduced pressure of 40 kPa. A microbiological analysis was conducted daily to examine the microbial contamination, which included counting the colonies of Pseudomonas spp., aerobic bacteria, lactic acid bacteria (LAB), Salmonella, and Escherichia coli, as well as monitoring the increase in pH levels. The results demonstrated a statistically significant difference (p > 0.05) in the aerobic bacteria counts between the storage conditions and storage days in all samples, which is a primary indicator of microbial spoilage. In contrast, the differences varied in the Pseudomonas spp. and LAB counts between the storage conditions and storage days, and there was no significant difference (p < 0.05) in the pH levels between the storage conditions. The results indicate that the combination of UV-C irradiation and vacuum sealing effectively inhibits microbial growth and extends the shelf-life of beef, chicken, and salmon fillets by 66.6%.

Pulsed Light Application for Campylobacter Control on Poultry Meat and Its Effect on Colour and Volatile Profile

Campylobacter on poultry meat needs to be controlled to reduce the risk of infection caused by the consumption of chicken meat. Pulsed light (PL) application on poultry meat was studied to control Campylobacter spp. The effect of this technology was evaluated regarding poultry meat colour and volatile compound changes. Two breast sample groups were prepared: inoculated with Campylobacter (107 bacteria of Campylobacter jejuni strains) and not inoculated. Samples were submitted to PL, five pulses/s of 300 ms, 1 Hz, and 1 J/cm2 in the apparatus, PL Tecum unit (Claranor). A response surface experimental design was applied regarding the factors of voltage (1828 to 3000 W) and distance to the source UV lamp (2.6 to 5.4 cm). The binomial factorial treatment (voltage and distance) with PL induced different energy doses (fluence J/cm2) received by samples, 2.82 to 9.67 J/cm2. Poultry meat pulsed light treated had a significant decrease of Enterobacteriaceae counts. The treatments applied were unable to reduce 1 log Campylobacter cfu/g of poultry meat. The poultry meat PL treated became slightly light, redder, and yellower than those not treated. PL can decrease the proportion of aldehydes on total volatiles in meat, particularly on those associated with chicken-like, chicken skin-like, and sweet odour notes in fresh poultry meat. Further studies of PL with higher energy doses will be necessary to confirm if there are Campylobacter reductions and about poultry meat treated under storage to evaluate if volatile compounds can affect the flavour of PL-treated meat samples.

Effect of Pulsed Light on Quality of Shelled Walnuts

Shelled walnuts are considered a microbiologically low-risk food but have been linked to some outbreaks, and a treatment aiming to decrease this risk is desirable. Pulsed light (PL) may be an alternative, providing it does not seriously impair their quality. This work assessed the impact of PL on some quality attributes of walnuts. To do this, measurements of rancidity, volatiles, total phenols, antioxidant activity, and descriptive sensory analysis were carried out on untreated and PL (43 J/cm2)-treated kernels. PL had no statistically significant (p > 0.05) effects on TBARS, peroxide value, total phenols, and antioxidant activity but significantly increased the concentration of volatiles related to green/herbaceous odors and decreased compounds related to fruity and citrus odors. The descriptors nut overall, walnut odor and flavor, and aftertaste were given statistically significantly (p < 0.05) higher scores, while descriptors woody odor and sweet received lower scores; 16 other traits such as all those related to color, texture, and rancidity were unaffected. No significant (p > 0.05) effects on total phenols and antioxidant activity in general were observed during the course of PL treatment. It can be concluded that PL technology may be used in shelled walnuts with only mild effects on their quality; a storage study must be carried out in order to determine the effect of PL treatment on its shelf-life.

Improved microbial and sensory quality of chicken meat by treatment with lactic acid, organic acid salts and modified atmosphere packaging

Microbial contamination and growth play important roles in spoilage and quality loss of raw poultry products. We evaluated the suitability of three commercially available organic acid based antimicrobial compounds, Purac FCC80 (l-lactic acid), Verdad N6 (buffered vinegar fermentate) and Provian K (blend of potassium acetate and diacetate) to prevent growth of the innate microbiota, reduce spoilage and enhance the sensory quality of raw chicken under vacuum, high CO₂ (60/40% CO₂/N₂), and high O₂ (75/25% O₂/CO₂) modified atmosphere (MA) storage conditions. Solutions were applied warm (50 °C) or cold (4 °C) to reflect treatments prior to (Prechill) or after (Postchill) cooling of chicken carcasses, respectively. Single postchill treatments of raw chicken wings with 5% Verdad N6 or Provian K solutions and MA storage enabled complete growth inhibition during the first seven days of storage before growth resumed. Enhanced bacterial control was obtained by combining Prechill lactic acid and Postchill Verdad N6 or Provian K treatments which indicated initial reductions up to 1.1 log and where total bacterial increase after 20 days storage was limited to 1.8-2.1 log. Antibacterial effects were dependent on the concentration of the inhibiting salts used, pH and the storage conditions. Bacterial community analyses showed increased relative levels of Gram-positive bacteria and with reductions of potential spoilage organisms in samples treated with the organic acid salts Verdad N6 and Provian K. Sensory analyses of raw, treated wings showed prominent lower scores in several spoilage associated odour attributes when compared with untreated chicken wings after 13 days storage. For heat-treated chicken, only minor differences for 22 tested attributes were detected between seven antimicrobial treatments and untreated control chicken. Immersion in commercially available organic acid/salt solutions combined with MA storage can reduce bacterial levels, improve microbial and sensory quality, and potentially improve shelf life and reduce food waste of chicken products.

Survival of Escherichia coli in Airborne and Settled Poultry Litter Particles

Airborne Escherichia coli (E. coli) in the poultry environment can migrate inside and outside houses through air movement. The airborne E. coli, after settling on surfaces, could be re-aerosolized or picked up by vectors (e.g., caretakers, rodents, transport trucks) for further transmission. To assess the impacts of airborne E. coli transmission among poultry farms, understanding the survivability of the bacteria is necessary. The objective of this study is to determine the survivability of airborne E. coli, settled E. coli, and E. coli in poultry litter under laboratory environmental conditions (22–28 °C with relative humidity of 54–63%). To determine the survivability of airborne E. coli, an AGI-30 bioaerosol sampler (AGI-30) was used to collect the E. coli at 0 and 20 min after the aerosolization. The half-life time of airborne E. coli was then determined by comparing the number of colony-forming units (CFUs) of the two samplings. To determine the survivability of settled E. coli, four sterile Petri dishes were placed on the chamber floor right after the aerosolization to collect settled E. coli. The Petri dishes were then divided into two groups, with each group being quantified for culturable E. coli concentrations and dust particle weight at 24-h intervals. The survivability of settled E. coli was then determined by comparing the number of viable E. coli per milligram settled dust collected in the Petri dishes in the two groups. The survivability of E. coli in the poultry litter sample (for aerosolization) was also determined. Results show that the half-life time of airborne E. coli was 5.7 ± 1.2 min. The survivability of E. coli in poultry litter and settled E. coli were much longer with the half-life time of 15.9 ± 1.3 h and 9.6 ± 1.6 h, respectively. In addition, the size distribution of airborne E. coli attached to dust particles and the size distribution of airborne dust particles were measured by using an Andersen impactor and a dust concentration monitor (DustTrak). Results show that most airborne E. coli (98.89% of total E. coli) were carried by the dust particles with aerodynamic diameter larger than 2.1 µm. The findings of this study may help better understand the fate of E. coli transmitted through the air and settled on surfaces and evaluate the impact of airborne transmission in poultry production.

Effect of nonthermal treatments on selected natural food pigments and color changes in plant material

In recent years, traditional high-temperature food processing is continuously being replaced by nonthermal processes. Nonthermal processes have a positive effect on food quality, including color and maintaining natural food pigments. Thus, this article describes the influence of nonthermal, new, and traditional treatments on natural food pigments and color changes in plant materials. Characteristics of natural pigments, such as anthocyanins, betalains, carotenoids, chlorophylls, and so forth available in the plant tissue, are shortly presented. Also, the characteristics and mechanism of nonthermal processes such as pulsed electric field, ultrasound, high hydrostatic pressure, pulsed light, cold plasma, supercritical fluid extraction, and lactic acid fermentation are described. Furthermore, the disadvantages of these processes are mentioned. Each treatment is evaluated in terms of its effects on all types of natural food pigments, and the possible applications are discussed. Analysis of the latest literature showed that the use of nonthermal technologies resulted in better preservation of pigments contained in the plant tissue and improved yield of extraction. However, it is important to select the appropriate processing parameters and to optimize this process in relation to a specific type of raw material.

Pulsed Ultraviolet Light Treatment of Chicken Parts

With increasing production and consumption of chicken, it is appropriate to investigate the functionality and effectiveness of microbial reduction interventions and the qualitative effects they have on food. The effectiveness of pulsed ultraviolet (PUV) light applied to chicken on a moving conveyor was evaluated for inactivation of Escherichia coli on the surface of raw boneless/skinless (B/S) chicken breasts, B/S chicken thighs, and bone-in/skin-on chicken thighs. The conveyor height (distance from the flashlamp) and speed were set to deliver total energy fluences of 5, 10, 20, and 30 J/cm2 to the surface of the products. The product type by energy fluence interaction was significant (P = 0.015) for microbial reduction of E. coli. Exposure to PUV light for 5 and 30 J/cm2 resulted in Log10 reductions of 0.29 and 1.04 for B/S breasts, 0.34 and 0.94 for B/S thighs, and 0.10 and 0.62 for bone-in/skin-on thighs, respectively. Lipid oxidation and changes in color of chicken samples were evaluated after 30 J/cm2 of PUV light treatment. Lipid oxidation was measured at 0, 24, 48, and 120 h after the treatment. PUV light treatment did not produce significant (P &gt; 0.05) changes in lipid oxidation values for each product type. International Commission on Illumination L*, a*, and b* parameters were used to report lightness and color of samples before and after treatment for B/S breasts and thighs and bone-in/skin-on thighs. Color parameters were not significantly (P &gt; 0.05) affected by PUV light treatments. In conclusion, this study indicates that PUV light applied to the surface of raw chicken parts on a moving conveyor is an effective surface antimicrobial treatment while inducing minimal change in quality of the product over a 5-d storage period under aerobic conditions.

UV-C LED Irradiation Reduces Salmonella on Chicken and Food Contact Surfaces

Ultraviolet (UV-C) light-emitting diode (LED) light at a wavelength of 250–280 nm was used to disinfect skinless chicken breast (CB), stainless steel (SS) and high-density polyethylene (HD) inoculated with Salmonella enterica. Irradiances of 2 mW/cm² (50%) or 4 mW/cm² (100%) were used to treat samples at different exposure times. Chicken samples had the lowest Salmonella reduction with 1.02 and 1.78 Log CFU/cm² (p ≤ 0.05) after 60 and 900 s, respectively at 50% irradiance. Higher reductions on CB were obtained with 100% illumination after 900 s (>3.0 Log CFU/cm²). Salmonella on SS was reduced by 1.97 and 3.48 Log CFU/cm² after 60 s of treatment with 50% and 100% irradiance, respectively. HD showed a lower decrease of Salmonella, but still statistically significant (p ≤ 0.05), with 1.25 and 1.77 Log CFU/cm² destruction for 50 and 100% irradiance after 60 s, respectively. Longer exposure times of HD to UV-C yielded up to 99.999% (5.0 Log CFU/cm²) reduction of Salmonella with both irradiance levels. While UV-C LED treatment was found effective to control Salmonella on chicken and food contact surfaces, we propose three mechanisms contributing to reduced efficacy of disinfection: bacterial aggregation, harboring in food and work surface pores and light absorption by fluids associated with CB.

Combination of Natural Compounds With Novel Non-thermal Technologies for Poultry Products: A Review

Ensuring safe, fresh, and healthy food across the shelf life of a commodity is an ongoing challenge, with the driver to minimize chemical additives and their residues in the food processing chain. High-value fresh protein products such as poultry meat are very susceptible to spoilage due to oxidation and bacterial contamination. The combination of non-thermal processing interventions with nature-based alternatives is emerging as a useful tool for potential adoption for safe poultry meat products. Natural compounds are produced by living organisms that are extracted from nature and can be used as antioxidant, antimicrobial, and bioactive agents and are often employed for other existing purposes in food systems. Non-thermal technology interventions such as high-pressure processing, pulsed electric field, ultrasound, irradiation, and cold plasma technology are gaining increasing importance due to the advantages of retaining low temperatures, nutrition profiles, and short treatment times. The non-thermal unit process can act as an initial obstacle promoting the reduction of microflora, while natural compounds can provide an active obstacle either in addition to processing or during storage time to maintain quality and inhibit and control growth of residual contaminants. This review presents the application of natural compounds along with emerging non-thermal technologies to address risks in fresh poultry meat.

Effect of UV-C Irradiation and Lactic Acid Application on the Inactivation of Listeria monocytogenes and Lactic Acid Bacteria in Vacuum-Packaged Beef

The objective of this study was to test the effect of the combined application of lactic acid (0–5%) (LA) and UV-C light (0–330 mJ/cm²) to reduce Listeria monocytogenes and lactic acid bacteria (LAB) on beef without major meat color (L *, a *, b *) change and its impact over time. A two-factor central composite design with five central points and response surface methodology (RSM) were used to optimize LA concentration and UV-C dose using 21 meat pieces (10 g) inoculated with L. monocytogenes (LM100A1). The optimal conditions were analyzed over 8 weeks. A quadratic model was obtained that predicted the L. monocytogenes log reduction in vacuum-packed beef treated with LA and UV-C. The maximum log reduction for L. monocytogenes (1.55 ± 0.41 log CFU/g) and LAB (1.55 ± 1.15 log CFU/g) with minimal impact on meat color was achieved with 2.6% LA and 330 mJ/cm² UV-C. These conditions impaired L. monocytogenes growth and delayed LAB growth by 2 weeks in vacuum-packed meat samples throughout 8 weeks at 4 °C. This strategy might contribute to improving the safety and shelf life of vacuum-packed beef with a low impact on meat color.

Biodegradable Active Packaging as an Alternative to Conventional Packaging: A Case Study with Chicken Fillets

Innovative active packaging has the potential to maintain the food quality and preserve the food safety for extended period. The aim of this study was to discover the effect of active films based on commercially available polylactic acid blend (PLA_b) and natural active components on the shelf life and organoleptic properties of chicken fillets and to find out; to what extent they can be used as replacement to the traditional packaging materials. In this study, commercially available PLA_b was compounded with citral and cinnamon oil. Active films with 300 µm thickness were then produced on a blown film extruder. The PLA_b-based films were thermoformed into trays. Fresh chicken breast fillets were packed under two different gas compositions, modified atmosphere packaging of 60% CO₂/40% N₂, and 75% O₂/25% CO₂ and stored at 4 °C. The effect of active packaging materials and gas compositions on the drip loss, dry matter content, organoleptic properties, and microbial quality of the chicken fillets were studied over a storage time of 24 days. The presence of active components in the compounded films was confirmed with FTIR, in addition the release of active components in the headspace of the packaging was established with GC/MS. Additionally, gas barrier properties of the packages were studied. No negative impact on the drip loss and dry matter content was observed. The results show that PLA_b-based active packaging can maintain the quality of the chicken fillets and have the potential to replace the traditional packaging materials, such as APET/PE trays.

The changing microbiome of poultry meat; from farm to fridge

Chickens play host to a diverse community of microorganisms which constitute the microflora of the live bird. Factors such as diet, genetics and immune system activity affect this complex population within the bird, while external influences including weather and exposure to other animals alter the development of the microbiome. Bacteria from these settings including Campylobacter and Salmonella play an important role in the quality and safety of end-products from these birds. Further steps, including washing and chilling, within the production cycle aim to control the proliferation of these microbes as well as those which cause product spoilage. These steps impose specific selective pressures upon the microflora of the meat product. Within the next decade, it is forecast that poultry meat, particularly chicken will become the most consumed meat globally. However, as poultry meat is a frequently cited reservoir of zoonotic disease, understanding the development of its microflora is key to controlling the proliferation of important spoilage and pathogenic bacterial groups present on the bird. Whilst several excellent reviews exist detailing the microbiome of poultry during primary production, others focus on fate of important poultry pathogens such as Campylobacter and Salmonella spp. At farm and retail level, and yet others describe the evolution of spoilage microbes during spoilage. This review seeks to provide the poultry industry and research scientists unfamiliar with food technology process with a holistic overview of the key changes to the microflora of broiler chickens at each stage of the production and retail cycle.

Investigating the Use of Ultraviolet Light Emitting Diodes (UV-LEDs) for the Inactivation of Bacteria in Powdered Food Ingredients

The addition of contaminated powdered spices and seasonings to finished products which do not undergo further processing represents a significant concern for food manufacturers. To reduce the incidence of bacterial contamination, seasoning ingredients should be subjected to a decontamination process. Ultraviolet light emitting diodes (UV-LEDs) have been suggested as an alternative to UV lamps for reducing the microbial load of foods, due to their increasing efficiency, robustness and decreasing cost. In this study, we investigated the efficacy of UV-LED devices for the inactivation of four bacteria (Listeria monocytogenes, Escherichia coli, Bacillus subtilis and Salmonella Typhimurium) on a plastic surface and in four powdered seasoning ingredients (onion powder, garlic powder, cheese and onion powder and chilli powder). Surface inactivation experiments with UV mercury lamps, UVC-LEDs and UVA-LEDs emitting at wavelengths of 254 nm, 270 nm and 365 nm, respectively, revealed that treatment with UVC-LEDs were comparable to, or better than those observed using the mercury lamp. Bacterial reductions in the seasoning powders with UVC-LEDs were less than in the surface inactivation experiments, but significant reductions of 0.75-3 log10 colony forming units (CFU) were obtained following longer (40 s) UVC-LED exposure times. Inactivation kinetics were generally nonlinear, and a comparison of the predictive models highlighted that microbial inactivation was dependent on the combination of powder and microorganism. This study is the first to report on the efficacy of UV-LEDs for the inactivation of several different bacterial species in a variety of powdered ingredients, highlighting the potential of the technology as an alternative to the traditional UV lamps used in the food industry.

Production of inactivated gram-positive and gram-negative species with preserved cellular morphology and integrity

There are many approaches available to produce inactive bacteria by termination of growth, each with a different efficacy, impact on cell integrity, and potential for application in standardized inactivation protocols. The aim of this study was to compare these approaches and develop a standardized protocol for generation of inactivated Gram-positive and Gram-negative bacteria, yielding cells that are metabolically dead with retained cellular integrity i.e., preserving the surface and limited leakage of intracellular proteins and DNA. These inactivated bacteria are required for various applications, for instance, when investigating receptor-triggered signaling or bacterial contact-dependent analysis of cell lines requiring long incubation times. We inactivated eight different bacterial strains of different species by treatment with beta-propiolactone, ethanol, formalin, sodium hydroxide, and pasteurization. Inactivation efficacy was determined by culturing, and cell wall integrity assessed by quantifying released DNA, bacterial membrane and intracellular DNA staining, and visualization by scanning electron microscopy. Based on these results, we discuss the bacterial inactivation methods, and their advantages and disadvantages to study host-microbe interactions with inactivated bacteria.

Service Robots in the Healthcare Sector

Traditionally, advances in robotic technology have been in the manufacturing industry due to the need for collaborative robots. However, this is not the case in the service sectors, especially in the healthcare sector. The lack of emphasis put on the healthcare sector has led to new opportunities in developing service robots that aid patients with illnesses, cognition challenges and disabilities. Furthermore, the COVID-19 pandemic has acted as a catalyst for the development of service robots in the healthcare sector in an attempt to overcome the difficulties and hardships caused by this virus. The use of service robots are advantageous as they not only prevent the spread of infection, and reduce human error but they also allow front-line staff to reduce direct contact, focusing their attention on higher priority tasks and creating separation from direct exposure to infection. This paper presents a review of various types of robotic technologies and their uses in the healthcare sector. The reviewed technologies are a collaboration between academia and the healthcare industry, demonstrating the research and testing needed in the creation of service robots before they can be deployed in real-world applications and use cases. We focus on how robots can provide benefits to patients, healthcare workers, customers, and organisations during the COVID-19 pandemic. Furthermore, we investigate the emerging focal issues of effective cleaning, logistics of patients and supplies, reduction of human errors, and remote monitoring of patients to increase system capacity, efficiency, resource equality in hospitals, and related healthcare environments.

Physical Methods for the Decontamination of Meat Surfaces

Purpose of Review

The market for minimally processed products is constantly growing due to consumer demand. Besides food safety and increased shelf life, nutritional value and sensory appearance also play a major role and have to be considered by the food processors. Therefore, the purpose of the review was to summarize recent knowledge about important alternative non-thermal physical technologies, including both those which are actually applied (e.g. high-pressure processing and irradiation) and those demonstrating a high potential for future application in raw meat decontamination (e.g. pulsed light UV-C and cold plasma treatment). The evaluation of the methods is carried out with respect to efficiency, preservation of food quality and consumer acceptance.

Recent Findings

It was evident that significantly higher bacterial reductions are achieved with gamma-ray, electron beam irradiation and high pressure, followed by pulsed light, UV-C and cold plasma, with ultrasound alone proving the least effective. As a limitation, it must be noted that sensory deviations may occur and that legal approvals may have to be applied for.

Summary

In summary, it can be concluded that physical methods have the potential to be used for decontamination of meat surfaces in addition to common hygiene measures. However, the aim of future research should be more focused on the combined use of different technologies to further increase the inactivation effects by keeping meat quality at the same time.

Impact of a Combination of UV-C Irradiation and Peracetic Acid Spray Treatment on Brochothrix thermosphacta and Yersinia enterocolitica Contaminated Pork

Efficient ways of decontamination are needed to minimize the risk of infections with Yersinia (Y.) enterocolitica, which causes gastrointestinal diseases in humans, and to reduce the numbers of Brochothrix (B.) thermosphacta to extend the shelf-life of meat. While many studies have focused on a single treatment of peracetic acid (PAA) or UV-C-irradiation, there are no studies about a combined treatment on meat. Therefore, in the present study, pork was inoculated with either Y. enterocolitica or B. thermosphacta, and was treated with a combination of 2040 mJ/cm² UV-C irradiation followed by a 2000 ppm PAA spray treatment (30 s). Samples were packed under modified atmosphere and stored for 1, 7, or 14 days. The samples were examined for Y. enterocolitica and B. thermosphacta content, chemical and sensory effects, and meat quality parameters. For Y. enterocolitica, a significant reduction of up to 2.16 log₁₀ cfu/cm² meat and for B. thermosphacta, up to 2.37 log₁₀ cfu/cm² meat was seen on day 14 after UV-C/PAA treatment compared to the untreated controls.

Listeria monocytogenes Biofilms in the Food Industry: Is the Current Hygiene Program Sufficient to Combat the Persistence of the Pathogen?

Biofilms contain microbial cells which are protected by a self-produced matrix and they firmly attach themselves to many different food industry surfaces. Due to this protection, microorganisms within biofilms are much more difficult to eradicate and therefore to control than suspended cells. A bacterium that tends to produce these structures and persist in food processing plants is Listeria monocytogenes. To this effect, many attempts have been made to develop control strategies to be applied in the food industry, although there seems to be no clear direction on how to manage the risk the bacteria poses. There is no standardized protocol that is applied equally to all food sectors, so the strategies for the control of this pathogen depend on the type of surface, the nature of the product, the conditions of the food industry environment, and indeed the budget. The food industry performs different preventive and corrective measures on possible L. monocytogenes-contaminated surfaces. However, a critical evaluation of the sanitization methods applied must be performed to discern whether the treatment can be effective in the long-term. This review will focus on currently used strategies to eliminate biofilms and control their formation in processing facilities in different food sectors (i.e., dairy, meat, fish, chilled vegetables, and ready-to-eat products). The technologies employed for their control will be exemplified and discussed with the objective of understanding how L. monocytogenes can be improved through food safety management systems.

Evaluation of UVC Radiation and a UVC-Ozone Combination as Fresh Beef Interventions against Shiga Toxin-Producing Escherichia coli, Salmonella, and Listeria monocytogenes and Their Effects on Beef Quality

ABSTRACT

This research study was conducted to evaluate treatments with UVC light and a combination of UVC and ozone that have recently received attention from the beef processing industry as antimicrobial interventions that leave no chemical residues on products. The effectiveness of UVC and UVC plus gaseous ozone treatments was evaluated for inactivation of pathogenic bacteria on fresh beef and for any impact on fresh beef quality. Fresh beef tissues were inoculated with cocktails of Shiga toxin-producing Escherichia coli (STEC) strains (serotypes O26, O45, O103, O111, O121, O145, and O157:H7), Salmonella, and Listeria monocytogenes. Inoculated fresh beef tissues were subjected to UVC or UVC-ozone treatments at 106 to 590 mJ/cm2. UVC treatment alone or in combination with ozone reduced populations of STEC, Salmonella, L. monocytogenes, and aerobic bacteria from 0.86 to 1.49, 0.76 to 1.33, 0.5 to 1.14, and 0.64 to 1.23 log CFU, respectively. Gaseous ozone alone reduced populations of E. coli O157:H7, Salmonella, and L. monocytogenes by 0.65, 0.70, and 0.33 log CFU, respectively. Decimal reduction times (D-values) for STEC serotypes, Salmonella, and L. monocytogenes on surfaces of fresh beef indicated that the UVC-ozone treatment was more effective (P ≤ 0.05) than UVC light alone for reducing pathogens on the surface of fresh beef. Exposure to UVC or UVC plus gaseous ozone did not have a deleterious effect on fresh meat color and did not accelerate the formation of oxidative rancidity. These findings suggest that UVC and UVC in combination with gaseous ozone can be useful for enhancing the microbial safety of fresh beef without impairing fresh beef quality.

HIGHLIGHTS

Unconventional Methods of Preserving Meat Products and Their Impact on Health and the Environment

A dual objective of food storage is to retain nutritional value and safe consumption over time. As supply chains have globalized, food protection and preservation methods have advanced. However, increasing demands to cater for larger volumes and for more effective food storage call for new technologies. This paper examines promising meat preservation methods, including high pressure process, ultrasounds, pulsating electric and magnetic field, pulsed light and cold plasma. These methods not only make it possible to obtain meat and meat products with a longer shelf life, safer for health and without preservatives, but also are more environment-friendly in comparison with traditional methods. With the use of alternative methods, it is possible to obtain meat products that are microbiologically safer, whilst also high quality and free from chemical additives. Moreover, these new technologies are also more ecological, do not require large quantities of energy or water, and generate less waste.

Efficacy of pulsed-ultraviolet light for inactivation of Salmonella spp on black peppercorns

Efficacy of pulsed ultraviolet (PUV) to inactivate Salmonella pure culture and on inoculated black peppercorns was evaluated. Black peppercorns inoculated with Salmonella were subjected to PUV treatment (0.28 J/cm² /pulse) using two different sample holders, on a traditional flat surface or on a wave-shaped surface to increase surface exposure of peppercorns to PUV through light reflection. The temperature change on black peppercorns surface during treatment was recorded, and the effect of cooling period during PUV treatment was studied. PUV treatment of two pulses reduced Salmonella population by more than 6 log CFU/mL in phosphate-buffered saline. Continuous PUV treatment (80 pulses on each side) using a wave-shaped surface was able to reduce Salmonella by 1.9 log CFU/g; same treatment using flat surface reduced Salmonella by less than 1.5 log CFU/g. The temperature on peppercorns surface increased to 65 °C after 80 pulses continuous PUV treatment. Adding 280 s cooling time after every 20 pulses reduced the temperature from 65 to 40 °C and achieved similar Salmonella inactivation (P > 0.05) as the continuous PUV treatment. Results from this study showcase the effectiveness of PUV treatment for reducing Salmonella level on black peppercorns surface and provided insights on the potential implementation of PUV treatment at the industrial level. PRACTICAL APPLICATION: Results from this study showcased the effectiveness of PUV treatment for reducing Salmonella level on black peppercorns surface and provided insights on the potential implementation of PUV treatment at the industrial level.

Treatment of pastirma with pulsed UV light: Modeling of Staphylococcus aureus inactivation and assessment of quality changes

The efficacy of pulsed UV (PUV) light treatment carried out in a wide range of fluence was investigated on pastirma slices by characterizing Staphylococcus aureus inactivation using mathematical models and by assessing the treatment effects on quality attributes. Pastirma slices inoculated on top surface with S. aureus were subjected to pulsed UV light for 5, 15, 25, 35, and 45 s at 5, 8, and 13 cm from the quartz window. Although the 5 cm/45 s treatment (72.3 J/cm²) yielded a maximum reduction of 2.99 log cfu/cm² for S. aureus, this treatment changed the color, moisture, and thiobarbituric acid-reactive substances (TBARS) values of pastirma significantly (p < 0.05). The quality of pastirma tended to change above 20 J/cm², below which the highest log reduction of S. aureus was ∼1.3 log cfu/cm² obtained after the 8 cm/15 s treatment (18 J/cm²). Kamau's model provided better fit to inactivation data (root mean square error: 0.049-0.116, A_f: 1.013-1.046, R²: 0.991-0.999) than Cerf's and Weibull models.

Inactivation of Yersinia enterocolitica and Brochothrix thermosphacta on pork by UV-C irradiation

Ultraviolet (UV) irradiation has gained interest as a decontamination method for food for several years. This study investigated how UV-C affected the microbial load of pork, inoculated with Yersinia (Y.) enterocolitica and Brochothrix (B.) thermosphacta. The initial effect as well as the effect after 1, 7 and 14 days of storage were investigated. Additionally, the meat quality parameters color, pH value, myoglobin redox form percentages and antioxidant capacity were analyzed. During storage, the bacterial load on pork was significantly reduced up to 1.2 log₁₀ using doses of 408 or 2040 mJ/cm². In contrast to this, in vitro experiments with bacterial suspensions showed that calculated UV doses of 16.16 and 19.30 mJ/cm² resulted in a 3.0 log₁₀ reduction of Y. enterocolitica and B. thermosphacta, respectively. The analyzed meat quality parameters were not influenced by UV-C treatment. Hence, UV-C light can reduce microbial surface contamination without negatively affecting meat quality.

Inactivation of Staphylococcus aureus and Escherichia coli O157:H7 on fresh kashar cheese with pulsed ultraviolet light

Pulsed ultraviolet light is a potential postprocessing decontamination method which is able to reduce pathogens on solid food surfaces. Cheese surfaces may become easily contaminated with pathogens due to improper handling or contact with unhygienic surfaces during or after processing. In this study, the effects of pulsed ultraviolet light on Staphylococcus aureus and Escherichia coli O157:H7 on fresh kashar cheese were investigated. Pulsed ultraviolet light was applied to kashar cheese for different times (5, 15, 30, 45, 60 s) at 5, 8, and 13 cm from the quartz window in a pulsed ultraviolet light system. Based on the inactivation level, time, and visual evaluation, the most favorable treatment was determined as the 45 s-13 cm treatment (∼44 J/cm²). This treatment yielded about 1.62 and 3.02 log₁₀ reductions (cfu/cm²) for S. aureus and E. coli O157:H7, respectively, while did not alter (p>0.05) the pH, lipid oxidation, and moisture content of kashar cheese, except the color parameters. When 0.5 cm thick kashar cheese was treated with pulsed ultraviolet light at a distance of 5 cm from the quartz window, the highest energy transmittance was found to be about 9.16%. These findings demonstrate that pulsed ultraviolet light has the potential for postprocessing decontamination of semi-hard cheese surfaces.

Pulse UV light effect on microbial biomolecules and organic pollutants degradation in aqueous solutions

This study present assessed the effect of UV pulsed light (PL) on microbial and organic pollutants using two spiral lamps were used, i.e., PL1 and PL2 lamps, with wavelength cut-offs of 190 and 240 nm, respectively. Overall, our study demonstrated that pulsed UV light impacts several microbial biomolecules and degrades polycyclic aromatic hydrocarbons (PAHs) in aqueous solution. In microbial inactivation by PL2, temporary changes of bacterial cellular components, specifically proteins, were observed, but the compositional changes of bacteria that were exposed to PL1 were permanent due to ozonolysis. PL1 irradiation caused greater deactivation of the bacteria than PL2 irradiation due to the generation of ozone. The higher efficacy of PL1 in terms of membrane disruption, reduction of respiration rate, and reduction of growth rate was due to the production of ozone during the irradiation period. The bacteria that were irradiated with both PL lamps regrew due to photoreactivation, such as an enzymatic DNA-repair mechanism. The PAH degradation kinetics indicate that higher molecular weights degraded faster than those with lower molecular weights. For both lamps, the degradation of naphthalene and fluorene was first order, whereas second order for pyrene and anthracene. Any effect of ozonolysis on the PAH degradation rates was not apparent, which indicated that photolysis was the primary degradation pathway. PAH solutions treated with both pulsed UV lamps did not result in a toxicity effect on the bacteria.