Application of Pulsed Light to Sliced Cheese: Effect on Listeria Inactivation, Sensory Quality and Volatile Profile

Abstract

Two cheese varieties with different surface features (Gouda and Manchego) were tested for pulsed light decontamination of Listeria sp. on ready-to-eat presentations. Sensory quality and volatile profile were also studied. Cheese slices were flashed with fluences comprised between 0.9 and 8.4 J/cm 2 . The treatment was less effective in Manchego than in Gouda, in which 3 log cfu/cm 2 were obtained with 0.9 J/cm 2 . No sensory changes were observed due to the application of this dose. In Manchego slices, the maximum inactivation obtained was lower than 1 log cfu/cm 2 even at the highest fluence used. In both cheeses, differences in odour and flavour were reported immediately after treatment for fluences ≥4.2 J/cm 2 , due to the development of sulfur notes. Volatile analysis showed an increase of sulfur compounds which could explain these observations. The concentration of sulfur volatiles and the corresponding sensory notes disappeared during cold storage. In view of these results, pulsed light could be considered a useful strategy to decontaminate smoothsurface ready-to-eat cheeses.

Packaging aspects for processing and quality of foods treated by pulsed light

“…by Fernández et al (2016). For both cheeses, researchers reported differences in aroma and flavor immediately after treatments with fluences ≥4.2 J/cm 2 .…”

“…In other cases, the barrier properties of the films were characterized before pulsed light treatment. The study by Fernández, Hospital, Arias, and Hierro (2016) that packed cheeses in PA/PE (60 μm) with water vapor transmission rate <10 g m −2 day −1 and oxygen transmission rate of 75 cm 3 m −2 day −1 . In addition, Avalos-Llano, Martín-Belloso, and Soliva-Fortuny (2018), Avalos et al (2016), and Aguiló-Aguayo, Oms-Oliu, Martín-Belloso, and Soliva-Fortuny (2014) packaged freshcut strawberries, apples and avocados in transparent thermo-sealed polypropylene trays with film (64 µm) (material not specified) and permeability to oxygen of 110 cm 3 m −2 bar −1 day −1 (23°C/0% RH) and transmittance of 85% for wavelengths between 200-320 nm, 97% for general incident UV radiation (200-400 nm) and almost 100% of visible infrared radiation (400-1,100 nm).…”

“…In other cases, the barrier properties of the films were characterized before pulsed light treatment. The study by Fernández, Hospital, Arias, and Hierro (2016) that packed cheeses in PA/PE (60 μm) with water vapor transmission rate <10 g m −2 day −1 and oxygen transmission rate of 75 cm 3 m −2 day −1 . In addition, Avalos‐Llano, Martín‐Belloso, and Soliva‐Fortuny (2018), Avalos et al.…”

“…Currently, a wide variety of cheeses are commercialized as ready‐to‐eat products (Fernández et al., 2016). However, cheeses are susceptible to bacterial post‐processing contamination during cutting, handling, or packaging steps, which can lead to food safety issues and significant losses due to deterioration (Proulx et al., 2015).…”

Analysis of Volatile Components in Different Ophiocordyceps sinensis and Insect Host Products

“…2,2,4,4-tetramethyloctane is also the major compound of all the liquid fermentation samples (FC20d, FC40d, FC60d, FC80d, and FC100d). It was reported also in aged vinegar as an aroma compound [35], common wasp Vespula vulgaris colonies [36], Manchego and Gouda cheeses [37], Allium macrostemon flowers and aerial parts [38], the seeds and leaves of Synsepalum dulcificum [39], green teas [40], dry-cured meat products [41], and the stem of Guanyin tea [42]. It appears that this volatile mainly acts as an aroma compound from the plants and foods.…”