Surface UV-C light treatments to prolong the shelf-life of Fiordilatte cheese

Carbon dots from sour whey to develop a novel antimicrobial packaging for fiordilatte cheese

In this study, monodispersed and quasi-spherical C-Dots with an average size of 7.2 nm were successfully synthesized from sour whey solution by a hydrothermal method (200 °C for 9 h) for fiordilatte cheese packaging. C-Dots (2500 and 5000 mgL-1) were added to the cheese through an alginate-based coating or directly to the cheese brine. No significant changes in TM4 cell viability were observed at concentrations lower than 10,000 mgL-1. Microbiological and sensory properties of cheese coated and uncoated with C-Dots indicate a substantial preserving effect of the C-Dots. The uncoated control fiordilatte exhibited unacceptable levels of microbial proliferation within 3.5 days. Conversely, the coated cheese remained within acceptable limits, effectively doubling its shelf life compared to the control, primarily due to the coating protection rather than the addition of C-Dots. When compared to the control fiordilatte, the addition of C-Dots in the brine at 5000 mgL-1 resulted in an extension of over 10 days in cheese shelf life. Considering the significance of the sustainable approach in C-Dots synthesis and the exceptional use of C-Dots in the food industry, these findings hold great potential in terms of research and industrial applications.

Evaluation of the impact of UV radiation on rheological and textural properties of food

Demand for healthy, safe, and high-quality foods and disadvantages of thermal processing methods such as quality losses supported the improvement of the novel, affordable, and quick nonthermal food preservation techniques such as UV light. UV-C light (200-280 nm) radiation is an emerging technology for the disinfection of pathogen microorganisms, increasing the shelf life of foods, and used for pasteurization, surface sterilization, cleaning of equipment and water, and so on. Sensory perceptions of foods are effective on the consumer choice, acceptability, and consumption of foods. Rheology term, which also includes texture and mouthfeel, is primarily important for sensory perception, processing of foods, and shelf stability. Therefore, the determination of the effect of different processing methods on the textural and rheological properties of the food products is important. Rheological and textural changes generally occur in the surface of UV-C-irradiated samples due to the low penetration of UV-C light. The UV light treatment may cause internal disruption of cell membranes, which in turn cause loss of turgidity, weaken the cell walls, and contraction of tissues, which are related to the changes in the textural and rheological properties of foods. The present review focuses on the effect of UV-C radiation on the rheology and textural properties of food products.

Possibilities of using the continuous type of UV light on the surface of lor (whey) cheese: impacts on mould growth, oxidative stability, sensory and colour attributes during storage

This research paper addresses the hypothesis that the optimum doses of a continuous type of ultraviolet (UV) light applied to the surface of lor (whey) cheese needs to be identified to maximize mould inactivation and shelf life while minimizing quality deterioration. Therefore, the mould inactivation, protein and lipid oxidation products, sensory and colour attributes of lor cheese subjected to different doses of UV light (1.617, 4.018, and 36.832 kJ/m2) in a continuous type of UV system were evaluated. UV treated samples presented mould counts lower than those of untreated ones. UV treatment at more than 4.018 kJ/m2 allowed around 0.7-2.7 log reductions on mould growth during storage. The increase in UV light dose caused significant increases in primary and secondary lipid oxidation products. In particular, the highest doses applied to the surface of cheese samples had the highest values of protein carbonyls, as well as lipid oxidation products. Strong positive correlations were recorded between lipid and protein oxidation markers. Exposure to the highest doses of UV light increased foreign flavour perception, probably due to the oxidative reactions. The results indicated that the application of UV light to the lor cheese surface allowed delaying mould growth during storage but extreme doses could induce lipid and protein oxidation reactions, leading to quality deterioration.

Non-thermal Processing Technologies for Dairy Products: Their Effect on Safety and Quality Characteristics

Thermal treatment has always been the processing method of choice for food treatment in order to make it safe for consumption and to extend its shelf life. Over the past years non-thermal processing technologies are gaining momentum and they have been utilized especially as technological advancements have made upscaling and continuous treatment possible. Additionally, non-thermal treatments are usually environmentally friendly and energy-efficient, hence sustainable. On the other hand, challenges exist; initial cost of some non-thermal processes is high, the microbial inactivation needs to be continuously assessed and verified, application to both to solid and liquid foods is not always available, some organoleptic characteristics might be affected. The combination of thermal and non-thermal processing methods that will produce safe foods with minimal effect on nutrients and quality characteristics, while improving the environmental/energy fingerprint might be more plausible.

Antihypertensive Peptides from Ultrafiltration and Fermentation of the Ricotta Cheese Exhausted Whey: Design and Characterization of a Functional Ricotta Cheese

Aiming at valorizing the ricotta cheese exhausted whey (RCEW), one of the most abundant by-products from the dairy industry, a biotechnological protocol to obtain bioactive peptides with angiotensin-I-converting enzyme (ACE)—inhibitory activity was set up. The approach was based on the combination of membrane filtration and fermentation. A Lactobacillus helveticus strain selected to be used as starter for the fermentation of the ultrafiltration protein-rich retentate (R-UF) obtained from RCEW. The fermented R-UF was characterized by a high anti-ACE activity. Peptides responsible for the bioactivity were purified and identified through nano-LC–ESI–MS/MS. The sequences identified in the purified active fractions of the fermented R-UF showed partial or complete overlapping with previously reported κ-casein antihypertensive fragments. The fermented R-UF was spray-dried and used to enrich ricotta cheese at different fortification level (1 and 5% w/w). An integrated approach including the assessment of the microbiological, chemical, functional, textural, and sensory properties was used to characterize the fortified products. A significantly higher anti-ACE activity was found in the ricotta cheese fortified with fermented R-UF as compared to the control and to the samples obtained with the unfermented R-UF fraction at the same levels of fortification. In particular, a 100 g portion of the ricotta cheese produced at 5% fortification level contained circa 30 mg of bioactive peptides. The fortification led to a moderate acidification, increased hardness and chewiness, and decreased the milk odor and taste of the ricotta cheese as compared to the control, while flavor persistence and sapidity improved.

UV Light Application as a Mean for Disinfection Applied in the Dairy Industry

Thermal treatment is the most popular decontamination technique used in the dairy industry to ensure food protection and prolong shelf life. But it also causes nutrient and aroma degradation, non-enzymatic browning, and organoleptic changes of dairy products. Non-thermal solutions, on the other hand, have been extensively explored in a response to rising market demand for more sustainable and safe goods. For a long time, the use of ultraviolet (UV) light in the food industry has held great promise. Irradiation with shortwave UV light has excellent germicidal properties, which can destroy a variety of microbial pathogens (for example bacteria, fungi, molds, yeasts, and viruses), at low maintenance and installation costs with minimal use of energy to preserve food without undesirable effects of heat treatment. The purpose of this review is to update the studies made on the possibilities of UV-C radiation while also addressing the essential processing factors involved in the disinfection. It also sheds light on the promise of UV light-emitting diodes (UV-LEDs) as a microbial inactivation alternative to conventional UV lamps.

Application of batch system ultraviolet light on the surface of kashar cheese, a kind of pasta-filata cheese: effects on mould inactivation, lipid oxidation, colour, hardness and sensory properties

This research paper addresses the hypothesis that the application of ultraviolet (UV) light before packaging of pasta-filata cheese has the potential to eliminate or control post-processing contamination whilst maintaining chemical and sensorial quality. The surfaces of kashar cheese were treated at different doses of UV light (0.32-9.63 kJ/m2) in a batch UV cabinet system to determine effects on physicochemical and sensorial quality as well as mould inactivation. Untreated cheese samples were also used for comparison. Kashar cheese was naturally contaminated in a mouldy environment to provide the desired mould numbers before UV treatments. Log reductions of 0.34, 0.69 and 2.49 were achieved in samples treated at doses of 0.32, 0.96 and 1.93 kJ/m2, respectively and the mould count of sample treated at 9.63 kJ/m2 was below the detection limit. We found no significant differences in composition and hardness values between any of the treated or control cheeses. Although some individual colour values increased as the UV doses increased, this change was not observed visually in sensory analysis. Increased light intensity accelerated the lipid oxidation causing a perception of off-flavour. The results of this study show that it is necessary to examine the relationship between the oxidative and sensory interactions while determining the effective doses applied to cheese surface for microbial inactivation.

The effect of different ultraviolet-C light doses on microbial reduction and the components of camel milk

As a result of increasing interest in non-thermal technologies as a possible alternative or complementary to milk pasteurization processing, the objectives of this study were to determine the effects of different ultraviolet-C light doses on the viability of Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium and chemical changes to camel milk components. Pasteurized and inoculated camel milk samples were ultraviolet-C treated in a continuous flow system. The viability of E. coli O157:H7 and S. Typhimurium was evaluated with both in vivo imaging system and traditional plate count agar method. Samples subjected to the 4.15, 8.30, and 12.45 mJ/cm² of ultraviolet-C treatment resulted in 1.9, 3.3, and 3.9-log reductions in E. coli O157:H7 and 0.9, 3, and 3.9-log reductions in S. Typhimurium, respectively. The measurement of secondary lipid peroxidation products (or ThioBarbituric Acid Reactive Substance values) showed no significant (P > 0.05) differences between the raw and ultraviolet-C treated milk samples. Additionally, no changes (P > 0.05) in the protein profiles of α_s1-casein, α-lactalbumin, and lactoferrin were observed between both samples. Compared to the untreated raw milk, c9t11 conjugated linoleic acid decreased (P < 0.01) while t10c12 conjugated linoleic acid increased (P < 0.01) in the ultraviolet-C treated milk. Furthermore, three new volatile compounds were identified in the ultraviolet-C treated milk compared to the control. In conclusion, milk treated with the ultraviolet-C light at a dose of 12.45 mJ/cm² did not meet the Food and Drug Administration (FDA) requirements for the 5-log pathogen reduction. The ultraviolet-C treatment, on the other hand, had minimal effects on camel milk components.

Novel Technologies for Preserving Ricotta Cheese: Effects of Ultraviolet and Near-Ultraviolet-Visible Light

Ricotta cheese is a potential growth medium for a wide range of microorganisms. The aim of the current study was to investigate the efficacy of ultraviolet (UV-C) and near-ultraviolet-visible light (NUV-vis) in microbial decontamination of ricotta artificially inoculated with Pseudomonas fluorescens. Cheese samples were stored at 4 °C, and microbiological and sensory analyses were performed for 9 days. From the microbiological point of view, control samples became unacceptable after less than 5 days, whereas ricotta treated by both UV-C and NUV-vis light remained acceptable for more than 6 days. Similar effects of UV-C and NUV-vis light were also recorded in terms of sensory quality. The shelf life of the samples subjected to the treatments was thus extended by 50%, suggesting the potential application of UV-C and NUV-vis light for cheese decontamination.

High intensity light pulses to reduce microbial load in fresh cheese

The present study focused on the utilisation of High Intensity Light Pulses (HILP) treatment to preserve mozzarella cheese. First, the susceptibility of Pseudomonas fluorescens and Enterobacteriaceae to HILP (fluences from 0·39 to 28·0 J/cm2) in a transparent liquid was evaluated (in-vitro tests). Afterwards, the effects on inoculated mozzarella cheese were also assessed. Then untreated (Control) and HILP treated samples were packaged and stored at 10 °C for 2 weeks. Enterobacteriaceae, Pseudomonas spp. and pH were monitored during storage. In a transparent liquid (in-vitro tests) there was a significant microbial inactivation just with 2 s of treatment. On the inoculated cheese a relevant microbial reduction of about 1 log cycle was observed, according to the exposure to the treatments. For Pseudomonas spp. in particular, in the treated samples, the microbiological acceptability limit (106 cfu/g) was never reached after 2 weeks of refrigerated storage. To sum up, the efficacy of this treatment is very interesting because a microbial reduction was observed in treated samples. HILP treatment is able to control the microbial growth and may be considered a promising way to decontaminate the surface of mozzarella cheese.