Efficacy of Combined Sous Vide-Microwave Cooking for Foodborne Pathogen Inactivation in Ready-to-Eat Chicory Stems

Quality and Safety of Ready-to-Eat Golden Thistle (Scolymus hispanicus L.): A New Product for Traditional Italian Dishes

Golden thistle (Scolymus hispanicus L.) is a wild edible plant belonging to Asteraceae family, with a great potential for food applications. The aim of this study was to identify the best cooking procedure able to provide a high-quality, ready-to-use product. For this purpose, leaf midribs (the most used edible part of the plant) were cooked by boiling, steaming, and 'sous vide', and the cooked products were compared for their phenolic content and composition, antioxidant activity, sugar and inorganic ion content, organoleptic characteristics, and microbial safety, this latter also during storage. In general, boiling caused a decrease in the value of these parameters, despite being the best product for taste and overall acceptability. On the contrary, steaming and 'sous vide' resulted in the best treatments to preserve antioxidant activity, total phenols, and chlorogenic acid. In particular, in 'sous vide' cooked samples, a significant increase in the value of these parameters and a remarkable decrease in nitrate content were found. Moreover, 'sous vide' resulted in the best treatment also regarding microbial safety during shelf life; actually, after 15 days of storage at 8 °C, Enterobacteriaceae and mesophilic aerobic bacteria were not detectable in 'sous vide' samples. These results contributed to increase the knowledge of a wild edible plant with high nutritional properties and promoting its consumption by obtaining a ready-to-use product with good organoleptic characteristics and endowed with a long period of shelf life.

Quality changes of sous-vide cooked and blue light sterilized Argentine squid (Illex argentinus)

The present work was carried out to investigate the quality changes and shelf life of blue light (Blu-ray) irradiated sous-vide cooked (SVC) Argentine squid (Illex argentinus) during storage at 0, 5, and 10 °C. Sensory evaluation, color, shear force, lipid oxidation levels, total viable counts (TVC), and psychrophilic bacterial count were used to study the changes in storage quality of SVC squid at different temperatures. Results showed that the high-quality endpoints of Blu-ray irradiated Argentine squid were 360, 144, and 72 h, and the shelf-life endpoints were 504, 240, and 120 h during storage at 0, 5, and 10 ℃, respectively. The redness values of irradiated squid did not differ significantly (p >0.05) during the storage, the brightness and yellowness values of irradiated squid showed an increasing trend, and the sheer force initially increased and then decreased. The thiobarbituric acid reactive substance of each squid stored at low temperature increased with the extension of the storage period, indicating that they exhibited fat oxidation with the extension of the storage period. The TVC and the number of Psychrobacter species increased with the storage period. The correlation analysis suggested that TVC and Psychrobacter count as indicators of quality changes in Argentine squid during low-temperature storage were in good agreement with sensory scores (R2 >0.9). Additionally, our results showed that Blu-ray sterilization played a positive role by inducing photosensitive oxidation and decreasing TVC and the total number of Psychrobacter than the control group during storage of SVC squid after Blu-ray irradiation. This study provides a theoretical basis for applying Blu-ray sterilization in aquatic product processing.

Effect of different cooking methods on sensory quality assessment and in vitro digestibility of sturgeon steak

Sous vide can keep the nutritional properties and improve taste of food compared with other conventional methods. In addition, this method may reduce the risk of recontamination after cooking and during storage. The purpose of this paper was to study the effects of four cooking methods (steaming, microwaving, baking, and frying) on the sensory and digestibility on sturgeon steak pretreated by sous vide during the cold storage (0-25 days). The results showed that the digestibility of steaming and microwaving groups (range from 80.34% to 90.12%) significantly higher than that of the other treatment groups (p < .05); however, the overall acceptability of the two groups was lower. What more, the frying group has the highest acceptability and the lowest digestibility (range from 65.12% to 70.89%). The springiness (4.12-6.56 mm) and chewiness (1.75-3.12 mm) of the frying group were significantly higher than those of the other treatment groups, which was consistent with the results of scanning electron microscopy (SEM) that frying treatment group has a denser structure and smaller pores. With the prolonged refrigeration time, especially between 15 and 25 days, the volatile flavor components (nitrogen oxide, methane, and alcohol) and stagnant water (T21) were significantly decreased. Principal component analysis showed that the moisture content was the main factor affecting the overall acceptability and best consumption time of the sturgeon was within 15 days. Simulating the effects of home cooking conditions and refrigeration storage time on the quality of sturgeon steak provided a reference for consumers using similar products.

The public health risk posed by Listeria monocytogenes in frozen fruit and vegetables including herbs, blanched during processing

A multi-country outbreak of Listeria monocytogenes ST6 linked to blanched frozen vegetables (bfV) took place in the EU (2015-2018). Evidence of food-borne outbreaks shows that L. monocytogenes is the most relevant pathogen associated with bfV. The probability of illness per serving of uncooked bfV, for the elderly (65-74 years old) population, is up to 3,600 times greater than cooked bfV and very likely lower than any of the evaluated ready-to-eat food categories. The main factors affecting contamination and growth of L. monocytogenes in bfV during processing are the hygiene of the raw materials and process water; the hygienic conditions of the food processing environment (FPE); and the time/Temperature (t/T) combinations used for storage and processing (e.g. blanching, cooling). Relevant factors after processing are the intrinsic characteristics of the bfV, the t/T combinations used for thawing and storage and subsequent cooking conditions, unless eaten uncooked. Analysis of the possible control options suggests that application of a complete HACCP plan is either not possible or would not further enhance food safety. Instead, specific prerequisite programmes (PRP) and operational PRP activities should be applied such as cleaning and disinfection of the FPE, water control, t/T control and product information and consumer awareness. The occurrence of low levels of L. monocytogenes at the end of the production process (e.g. < 10 CFU/g) would be compatible with the limit of 100 CFU/g at the moment of consumption if any labelling recommendations are strictly followed (i.e. 24 h at 5°C). Under reasonably foreseeable conditions of use (i.e. 48 h at 12°C), L. monocytogenes levels need to be considerably lower (not detected in 25 g). Routine monitoring programmes for L. monocytogenes should be designed following a risk-based approach and regularly revised based on trend analysis, being FPE monitoring a key activity in the frozen vegetable industry.