Short Wave Ultraviolet Light (UV-C) Effectiveness in the Inactivation of Bacterial Spores Inoculated in Turbid Suspensions and in Cloudy Apple Juice

UV-C Light: A Promising Preservation Technology for Vegetable-Based Nonsolid Food Products

A variety of bioactive substances present in fruit- and vegetable-processed products have health-promoting properties. The consumption of nutrient-rich plant-based products is essential to address undernutrition and micronutrient deficiencies. Preservation is paramount in manufacturing plant-based nonsolid foods such as juices, purees, and sauces. Thermal processing has been widely used to preserve fruit- and vegetable-based products by reducing enzymatic and microbial activities, thereby ensuring safety and prolonged shelf life. However, the nutritional value of products is compromised due to the deleterious effects of thermal treatments on essential nutrients and bioactive compounds. To prevent the loss of nutrients associated with thermal treatment, alternative technologies are being researched extensively. In studies conducted on nonsolid food, UV-C treatment has been proven to preserve quality and minimize nutrient degradation. This review compiles information on the use of UV-C technology in preserving the nutritional attributes of nonsolid foods derived from fruit and vegetables. The legislation, market potential, consumer acceptance, and limitations of UV-C are reviewed.

Device for Identifying the UV Emission Spectrum

Nowadays, the disinfection of classrooms, shopping malls, and offices has become an important part of our lives. One of the most effective disinfection methods is ultraviolet (UV) radiation. To ensure the disinfection device has the required wavelength spectrum, we need to measure it with dedicated equipment. Thus, in this work, we present the development of a UV spectrum detector capable of identifying UV wavelength spectrums, with a wide range of probes and the ability to transmit data to a PC for later evaluation of the results. The device was developed with four UV sensors: one for UV-A, one for UV-B, one for UV-C, and one with a wide range of detection of UVA, with a built-in transimpedance amplifier. An Arduino Nano development board processes all the acquired data. We developed a custom light source containing seven UV LEDs with different central wavelengths to calibrate the device. For easy visualization of the results, custom PC software was developed in the Processing programming medium. For the two pieces of electronics—the UV detector and calibration device—3D-printed housings were created to be ergonomic for the end-user. From the price point of view, this device is affordable compared to what we can find on the market.

Fruit Juices: Technology, Chemistry, and Nutrition 2.0

In recent years, the food industry has increased its interest in the development of functional foods, including fruit juices, due to the increased demand among consumers for foods and beverages that benefit and improve our health [...]

Inactivation of Escherichia coli, Salmonella enterica and Listeria monocytogenes on apple peel and apple juice by ultraviolet C light treatments with two irradiation devices

Following the market trends, the consumption of fresh and cold-pressed juice in Europe is increasing. However, a primary concern - particularly in apple juice - is the related outbreaks caused by food-borne pathogens. One of the challenges is to find methods able to reduce pathogenic loads while avoiding deterioration of nutritional properties and bioactive compounds that occur in thermal pasteurization processes. In this study, the inactivation of Escherichia coli, Salmonella enterica and Listeria monocytogenes was evaluated under different ultraviolet C (UVC_254nm) light treatments (up to 10,665.9 ± 28.1 mJ/cm²), in two different steps of the production chain (before and after juice processing): on apple peel discs and in apple juice. The systems proposed were a horizontal chamber with UVC_254nm emitting lamps treating the product disposed at a distance of 12 cm, and a tank containing UVC_254nm lamps and in which the product is immersed and agitated. Final reductions ranged from 3.3 ± 0.5 to 5.3 ± 0.4 logarithmic units, depending on the microorganism, matrix and used device. The survival curves were adjusted to Weibull and biphasic models (R²-adj ≥ 0.852), and UVC doses needed for the first decimal reduction were calculated, being lower for the apple peel discs (0.20 to 83.83 mJ/cm²) than they were for apple juice (174.60 to 1273.31 mJ/cm²), probably for the low transmittance of the apple juice compared to the surface treatment occurring on the peels. Within the treatments evaluated, the UVC_254nm irradiation of apple peels immersed in water was the best option as it resulted in a reduction of the tested microorganisms of ca. 2-3 log units at lower UVC_254nm doses (< 500 mJ/cm²) when compared to those occurring in apple peel treated with the UVC chamber and in juice. As contamination can proceed from apples, the sanitization of these fruit prior to juice production may be helpful in reducing the safety risks of the final product, reducing the drawbacks related to the poor transmittance of the fruit juices.