Microbial and quality improvement of boiled gansi dish using carbon dots combined with radio frequency treatment

Reduction in bacterial culture positivity rates at a human milk bank facility of a tertiary care hospital: a quality improvement initiative

BACKGROUND

Human milk banks (HMBs) offer the best feed for neonates after mother's own milk (MOM), especially when MOM is insufficient. Although HMBs are founded on standard protocols, contamination and wastage of milk due to positive milk cultures remain a problem. Present study was planned as a quality improvement (QI) initiative to reduce culture rates at the HMB.

AIMS STATEMENT

The aim is to reduce the milk-culture positivity rates at the HMB by 50% or more, over a span of 3 months.

MATERIALS AND METHODS

A QI initiative was undertaken at the milk bank of a tertiary-care hospital in Western Maharashtra in 2020. All human milk cultures sent since January 2018 were recorded from the data at HMB registry. The milk-culture rates had increased from 105/4376 to 125/3823 between 2018 and 2019. A fishbone analysis identified sources of contamination of donor milk during 2018-2019. PDSA (Plan Do Study Act) cycles begun from 2020, interventions aimed at reducing milk-culture positivity rates were tried, namely improved hand-hygiene, sanitisation of milk donors before collection, steam sterilisers for breast-pump accessories and recruitment of staff nurses at all stages of milk handling.

RESULTS

Milk-culture growths had increased from 105/4376 (2.37%) in 2018 to 125/3823 (3.27%) in 2019 and then declined to 23/2103 (1.09%) in 2020, 12/2345 (0.51%) in 2021, 9/2985 (0.30%) in 2022 and 1/1322 (0.08%) in June 2023. The unit achieved reduction of over 99% in milk wastage during this period. This improvement was sustained till 2023 with consistent increment in quality of consumable donor milk.

CONCLUSIONS

The QI initiative was successful and led to significant decrease in milk-culture rates, which has been well sustained. The measures that led to the improvement in the quality of milk at the HMB were improvement in hand hygiene, use of steam sterilisers and presence of committed individuals at all stages of milk handling. These methods are simple, easily replicated and sustainable with a promise of ensuring a steady supply of high-quality human milk.

3D printing technology for prepared dishes: printing characteristics, applications, challenges and prospects

Prepared dishes are popular convenience foods that meet the needs of consumers who pursue delicious tastes while saving time and effort. As a new technology, food 3D printing (also known as food additive manufacturing technology) has great advantage in the production of personalized food. Applying food 3D printing technology in the production of prepared dishes provides the solution to microbial contamination, poor nutritional quality and product standardization. This review summarizes the problems faced by the prepared dishes industry in traditional food processing, and introduces the characteristics of prepared dishes and 3D printing technology. Food additives are suitable for 3D prepared dishes and novel 3D printing technologies are also included in this review. In addition, the challenges and possible solutions of the application of food 3D printing technology in the field of prepared dishes are summarized and explored. Food additives with advantages in heat stability, low temperature protection and bacteriostasis help to accelerate the application of 3D printing in prepared dishes industry. The combination of 3D printing technology with heat-assisted sources (microwave, laser) and non-heat-assisted sources (electrolysis, ultrasound) provides the possibility for the development of customized prepared dishes in the future, and also promotes more 3D food printing technologies for commercial use. It is noteworthy that these technologies are still at research stage, and there are challenges for the formulation design, the stability of printed ink storage, as well as implementation of customized nutrition for the elderly and children.

Electromagnetic wave-based technology for ready-to-eat foods preservation: a review of applications, challenges and prospects

In recent years, the ready-to-eat foods market has grown significantly due to its high nutritional value and convenience. However, these foods are also at risk of microbial contamination, which poses food safety hazards. Additionally, traditional high-temperature sterilization methods can cause food safety and nutritional health problems such as protein denaturation and lipid oxidation. Therefore, exploring and developing effective sterilization technologies is imperative to ensure food safety and nutritional properties, and protect consumers from potential foodborne diseases. This paper focuses on electromagnetic wave-based pasteurization technologies, including thermal processing technologies such as microwave, radio frequency, and infrared, as well as non-thermal processing technologies like ultraviolet, irradiation, pulsed light, and photodynamic inactivation. Furthermore, it also reviews the antibacterial mechanisms, advantages, disadvantages, and recent applications of these technologies in ready-to-eat foods, and summarizes their limitations and prospects. By comparing the limitations of traditional high-temperature sterilization methods, this paper highlights the significant advantages of these pasteurization techniques in effectively inhibiting microbial growth, slowing lipid oxidation, and preserving food nutrition and flavor. This review may contribute to the industrial application and process optimization of these pasteurization technologies, providing an optimal choice for preserving various types of ready-to-eat foods.

Application of radio frequency energy in processing of fruit and vegetable products

Thermal processing is commonly employed to ensure the quality and extend the shelf-life of fruits and vegetables. Radio frequency (RF) heating has been used as a promising alternative treatment to replace conventional thermal processing methods with advantages of rapid, volumetric, and deep penetration heating characteristics. This article provides comprehensive information regarding RF heating uniformity and applications in processing of fruit and vegetable products, including disinfestation, blanching, drying, and pasteurization. The dielectric properties of fruits and vegetables and their products have also been summarized. In addition, recommendations for future research on RF heating are proposed to enhance practical applications for fruits and vegetables processing in future.

Effect of chitosan coating, carbon dots and ultrasound treatment on microorganisms and physicochemical quality of fresh-cut lettuce

The effect of chitosan (CH) coating, carbon dots (CDs) and ultrasound (US) treatment on microorganisms and the physicochemical quality of fresh-cut (FC) lettuce was investigated. FC lettuces were treated by US and dipped into CD/CH coating, then packed and stored for 15 d at 4 °C. Results presented that CD/CH coating exhibited a superior effect on the depressing growth of aerobic plate count, mould and yeast, the decrease of respiratory rate, the inhibition of peroxidase and polyphenol oxidase activities, the maintenance of ascorbic acid and chlorophyll contents, the reduction of mass loss, the restriction of water distribution in US-treated FC lettuce. This exhibited that CD/CH coating effectively kept the microbial and physicochemical quality of FC lettuce.

Carbon Dots-Types, Obtaining and Application in Biotechnology and Food Technology

Materials with a "nano" structure are increasingly used in medicine and biotechnology as drug delivery systems, bioimaging agents or biosensors in the monitoring of toxic substances, heavy metals and environmental variations. Furthermore, in the food industry, they have found applications as detectors of food adulteration, microbial contamination and even in packaging for monitoring product freshness. Carbon dots (CDs) as materials with broad as well as unprecedented possibilities could revolutionize the economy, if only their synthesis was based on low-cost natural sources. So far, a number of studies point to the positive possibilities of obtaining CDs from natural sources. This review describes the types of carbon dots and the most important methods of obtaining them. It also focuses on presenting the potential application of carbon dots in biotechnology and food technology.

Nanoparticle applications in food - a review

The use of nanotechnology in the food industry raises uncertainty in many respects. For years, achievements of nanotechnology have been applied mainly in biomedicine and computer science, but recently it has also been used in the food industry. Due to the extremely small (nano) scale, the properties and behavior of nanomaterials may differ from their macroscopic counterparts. They can be used as biosensors to detect reagents or microorganisms, monitor bacterial growth conditions, increase food durability e.g. when placed in food packaging, reducing the amount of certain ingredients without changing the consistency of the product (research on fat substitutes is underway), improve the taste of food, make some nutrients get better absorbed by the body, etc. There are companies on the market that are already introducing nanoparticles into the economy to improve their functionality, e.g. baby feeding bottles. This review focuses on the use of nanoparticles in the food industry, both organic (chitosan, cellulose, proteins) and inorganic (silver, iron, zinc oxide, titanium oxide, etc.). The use of nanomaterials in food production requires compliance with all legal requirements regarding the safety and quantity of nano-processed food products described in this review. In the future, new methods of testing nanoparticles should be developed that would ensure the effectiveness of compounds subjected to, for example, nano-encapsulation, i.e. whether the encapsulation process had a positive impact on the specific properties of these compounds. Nanotechnology has revolutionized our approach towards food engineering (from production to processing), food storage and the creation of new materials and products, and the search for new product applications.

New Insights into the Cellular Toxicity of Carbon Quantum Dots to Escherichia coli

In this study, the cytotoxicity and toxic mechanism of carbon quantum dots (CQDs) to E. coli were evaluated in vitro. The synthetic CQDs were extremely small in size (~2.08 nm) and displayed strong fluorescence. The results demonstrated that CQDs showed good biocompatibility with E. coli within a short culture time. However, when the exposure time exceeded 24 h, the toxicity of CQDs became apparent, and the contents of reactive oxygen species, lactate dehydrogenase, and the crystal violet absorption rate increased significantly. To further explore the cytotoxic mechanism, approaches including confocal laser scanning microscopy, scanning electron microscopy, and biological transmission electron microscopy combined with zeta potential tests, osmotic pressure measurement, and comet assays were performed. On the one hand, the CQDs altered the surface charges of cells and induced lipid peroxidation by adhesion on the surface of E. coli, leading to an increase in the permeability of the cell wall. On the other hand, when the concentration of CQDs reached 200 µg/mL, the osmotic pressure of the extracellular environment was significantly reduced. These are the main factors that lead to cell edema and death. Finally, the comet assays confirmed that CQDs could induce DNA damage, which could inhibit the proliferation of E. coli.

Advances in prepared dish processing using efficient physical fields: A review

Prepared dishes are increasingly popular convenience food that can be eaten directly from hygienic packaging by heating. Physics field (PF) is food processing method built with physical processing technology, which has the characteristics of high efficiency and environmental safety. This review focuses on summarizing the application of PFs in prepared dishes, evaluating and comparing PFs through quality changes during processing and storage of prepared dishes. Currently, improving the quality and extending the shelf life of prepared dishes through thermal and non-thermal processing are the main modes of action of PFs. Most PFs show good potential in handing prepared dishes, but may also react poorly to some prepared dishes. In addition, the difficulty of precise control of processing conditions has led to research mostly at the laboratory stage, but as physical technology continues to break through, more PFs and multi-physical field will be promoted for commercial use in the future. This review contributes to a deeper understanding of the effect of PFs on prepared dishes, and provides theoretical reference and practical basis for future processing research in the development of various enhanced PFs.

Carbon dot-based therapeutics for combating drug-resistant bacteria and biofilm infections in food preservation

Drug-resistant bacteria are caused by antibiotic abuse and/or biofilm formation and have become a threat to the food industry. Carbon dot (CD)-based nanomaterials are a very promising tools for combating pathogenic and spoilage bacteria, and they possess exceptional and adjustable photoelectric and chemical properties. In view of the rapid development of CD-based nanomaterials and their increasing popularity in the food industry, a comprehensive and updated review is needed to summarize their antimicrobial mechanisms and applications in foods. This review discusses the synthesis of CDs, antimicrobial mechanisms, and their applications for extending the shelf life of food. It includes the synthesis of CDs using small molecules, polymers, and biomass. It also discusses the different antimicrobial mechanisms of CDs and their use as antibacterial agents and carriers/ligands. CD-based materials have proven effective against pathogenic and spoilage bacteria in food by inhibiting planktonic bacteria and biofilms. Optimization of the production parameters of CDs can help them achieve a full-spectral response, but degradability still requires further research.

Nostoc sphaeroides Cyanobacteria: a review of its nutritional characteristics and processing technologies

Nostoc sphaeroides is an edible Cyanobacterium which has high nutritional value and is widely used in dietary supplements and therapeutic products. N. sphaeroides contains protein, fatty acid, minerals and vitamins. Its polysaccharides, phycobilin, phycobiliproteins and some lipids are highly bioactive. Thus, N. sphaeroides possesses anti-oxidation, anti-inflammation and cholesterol reducing functions. This paper reviews and evaluates the literature on nutritionally and functionally important compounds of N. sphaeroides. It also reviews and evaluates the processing of technologies used to process N. sphaeroides from fresh harvest to dry particulates including pretreatment, sterilization and drying, including their impact on sensorial and nutritional values. This review shows that a suitable combination of ultrasound, radio frequency and pulse spouted microwave with traditional sterilization and drying technologies greatly improves the sensorial and nutritive quality of processed N. sphaeroides and improves their shelf life; however, further research is needed to evaluate these hybrid technologies. Once suitably processed, N. sphaeroides can be used in food, cosmetics and pharmaceutical drugs as an ingredient.

Application of carbon dots in food preservation: a critical review for packaging enhancers and food preservatives

Carbon dots (CDs) have two unique advantages: one is ease of synthesis at low price, the other is desirable physical and chemical properties, such as ultra-small size, abundant surface functional groups, nontoxic/low-toxicity, good biocompatibility, excellent antibacterial and antioxidant activities etc. These advantages provide opportunities for the development of new food packaging enhancers and food preservatives. This paper systematically reviews the studies of CDs used to strengthen the physical properties of food packaging, including strengthen mechanical strength, ultraviolet (UV) barrier properties and water barrier properties. It also reviews the researches of CDs used to fabricate active packaging with antioxidant and/or antibacterial properties and intelligent packaging with the capacity of sensing the freshness of food. In addition, it analyzes the antioxidant and antibacterial properties of CDs as preservatives, and discusses the effect of CDs applied as coating agents and nano-level food additives for extension the shelf life of food samples. It also provides a brief review on the security and the release behavior of CDs.

Role of dehydration technologies in processing for advanced ready-to-eat foods: A comprehensive review

Advanced ready-to-eat foods, which can be consumed directly or only need simple processed before consumption, refer to the products that processing with cutting-edge food science and technology and have better quality attribute. Cold chain and chemical addition are commonly used options to ensure microbial safety of high moisture advanced ready-to-eat foods. However, this requires freezing/thawing processing at high cost or has undesirable residue. Dehydration treatment has the potential to compensate those shortcomings. This article reviewed the positive effects of dehydration on advanced ready-to-eat foods, current application status of dehydration technologies, novel dehydration related technologies and the pathogenic bacteria control of products. It is observed that dehydration treatment is receiving increasing attention for ready-to-eat foods including space foods, 3 D-printed personalized foods and formula foods for special medical purposes. Recently developed drying technologies such as pulsed spouted microwave freeze-drying and infrared freeze-drying have attracted much interest due to their excellent drying characteristics. Finally, intelligent drying, dehydration-nano-hybridization and dehydration-induced multi-dimensional modification technology are some of the emerging R and D areas in this field.

Effect of addition of carbon dots to the frying oils on oxidative stabilities and quality changes of fried meatballs during refrigerated storage

Carbon dots (CDs) were prepared and noted to exhibit potent scavenging activities against DPPH·, ·OH, and O₂^·- radicals. Addition of CDs to frying oil as a means to improve oxidative stability and minimize quality changes of fried meatballs during refrigerated storage was investigated in comparison with the use of tert-butylhydroquinone (TBHQ) and carnosic acid (CA). Compared with the control sample, 0.05% CDs significantly reduced thiobarbituric acid reactive substances value, carbonyl and total volatile basic nitrogen contents of fried meatballs. Both lipid and protein oxidation inhibition capabilities of CDs were higher than those of 0.05% CA but lower than those of 0.02% TBHQ. Total sensory score of sample with CDs (7.1 ± 0.06) was significantly higher than those of the control (4.7 ± 0.03) and sample with TBHQ (6.4 ± 0.04). CDs could delay oxidation of fried meatballs during refrigerated storage and can well serve as an alternative antioxidant.