MICROBIOLOGICAL QUALITY OF SOUS VIDE COOK-CHILL PRESERVED FOOD AT DIFFERENT SHELF LIFE

Advances and Drawbacks of Sous-Vide Technique-A Critical Review

The sous-vide (SV) technique, notable for its precision and ability to preserve food quality, has become a transformative method in culinary arts. This review examines the technical aspects, applications, and limitations of SV, focusing on its impact on food safety, nutritional retention, and quality parameters across various food matrices such as meats, seafood, vegetables, and semi-prepared products. Through an extensive literature review, the study highlights the use of natural inhibitors and essential oils to enhance microbial safety and explores the nutritional benefits of SV in preserving vitamins and minerals. The findings suggest that while SV offers significant benefits in terms of consistent results and extended shelf life, challenges remain in terms of equipment costs and the necessity for specific training, and although sufficient for food preparation/processing, its effectiveness in eliminating microbial pathogens, including viruses, parasites, and vegetative and spore forms of bacteria, is limited. Overall, the research underscores SV's adaptability and potential for culinary innovation, aligning with modern demands for food safety, quality, and nutritional integrity.

Biological Activity and Phytochemical Characteristics of Star Anise (Illicium verum) Essential Oil and Its Anti-Salmonella Activity on Sous Vide Pumpkin Model

Illicium verum, commonly known as star anise, represents one of the notable botanical species and is recognized for its rich reservoir of diverse bioactive compounds. Beyond its culinary application as a spice, this plant has been extensively utilized in traditional medicine. Given the contemporary emphasis on incorporating natural resources into food production, particularly essential oils, to enhance sensory attributes and extend shelf life, our study seeks to elucidate the chemical composition and evaluate the antibacterial (in vitro, in situ) and insecticidal properties of Illicium verum essential oil (IVEO). Also, microbiological analyses of pumpkin sous vide treated with IVEO after inoculation of Salmonella enterica were evaluated after 1 and 7 days of study. GC/MS analysis revealed a significantly high amount of (E)-anethole (88.4%) in the investigated EO. The disc diffusion method shows that the antibacterial activity of the IVEO ranged from 5.33 (Streptococcus constellatus) to 10.33 mm (Citrobacter freundii). The lowest minimal inhibition concentration was found against E. coli and the minimum biofilm inhibition concertation was found against S. enterica. In the vapor phase, the best antimicrobial activity was found against E. coli in the pears model and against S. sonei in the beetroot model. The application of the sous vide method in combination with IVEO application decreased the number of microbial counts and eliminated the growth of S. enterica. The most isolated microbiota identified from the sous vide pumpkin were Bacillus amyloliquefaciens, B. cereus, B. licheniformis, and Ralstonia picketii. Modifications to the protein composition of biofilm-forming bacteria S. enterica were suggested by the MALDI TOF MS instigations. The IVEO showed insecticidal potential against Harmonia axyridis. Thanks to the properties of IVEO, our results suggest it can be used in the food industry as a natural supplement to extend the shelf life of foods and as a natural insecticide.

Citrus limon Essential Oil: Chemical Composition and Selected Biological Properties Focusing on the Antimicrobial (In Vitro, In Situ), Antibiofilm, Insecticidal Activity and Preservative Effect against Salmonella enterica Inoculated in Carrot

New goals for industry and science have led to increased awareness of food safety and healthier living in the modern era. Here, one of the challenges in food quality assurance is the presence of pathogenic microorganisms. As planktonic cells can form biofilms and go into a sessile state, microorganisms are now more resistant to broad-spectrum antibiotics. Due to their proven antibacterial properties, essential oils represent a potential option to prevent food spoilage in the search for effective natural preservatives. In this study, the chemical profile of Citrus limon essential oil (CLEO) was evaluated. GC-MS analysis revealed that limonene (60.7%), β-pinene (12.6%), and γ-terpinene (10.3%) are common constituents of CLEO, which prompted further research on antibacterial and antibiofilm properties. Minimum inhibitory concentration (MIC) values showed that CLEO generally exhibits acceptable antibacterial properties. In addition, in situ antimicrobial research revealed that vapour-phase CLEO can arrest the growth of Candida and Y. enterocolitica species on specific food models, indicating the potential of CLEO as a preservative. The antibiofilm properties of CLEO were evaluated by MIC assays, crystal violet assays, and MALDI-TOF MS analysis against S. enterica biofilm. The results of the MIC and crystal violet assays showed that CLEO has strong antibiofilm activity. In addition, the data obtained by MALDI-TOF MS investigation showed that CLEO altered the protein profiles of the bacteria studied on glass and stainless-steel surfaces. Our study also found a positive antimicrobial effect of CLEO against S. enterica. The anti-Salmonella activity of CLEO in vacuum-packed sous vide carrot samples was slightly stronger than in controls. These results highlight the advantages of the antibacterial and antibiofilm properties of CLEO, suggesting potential applications in food preservation.

Development and Quality Characteristics of Elderly-Friendly Pulpo a La Gallega Prepared Using Texture-Modified Octopus (Octopus vulgaris) Arms

Considering the need for developing new senior-friendly processed seafood, this study aimed to develop octopus pulpo with high preference and excellent quality characteristics for elderly individuals by optimizing the vinegar immersion and sous vide softening treatment conditions for octopus (Octopus vulgaris) arms. The optimal sous vide heating temperature (70.0-100.0 °C), time (69.5-170.5 min), and vinegar concentration (0.2-0.8%) were established using response surface methodology (RSM). The pulpo prototype was produced using an octopus arm softened under optimal conditions and seasoned with a potato and olive oil sauce. The physicochemical and nutritional properties of the prototype were evaluated, followed by sensory evaluation and safety assessments. The hardness of softened octopuses obtained by 0.48% vinegar immersion and sous vide treatment (84.3 °C, 139.8 min), determined using RSM, was 394.5 × 1000 N/m2, showing a reduction of 83.0%; this was confirmed by electron microscopic observation. The texture of the pulpo prototype with softened octopus arms showed the highest preference (8.4 points) and high physicochemical and nutritional properties. Overall, the octopus pulpo a La Gallega prototype produced using texture-modified octopus arms was suitable for consumption by elderly people with chewing disorders and could help improve their quality of life.

Salmon (Salmo salar) Cooking: Achieving Optimal Quality on Select Nutritional and Microbiological Safety Characteristics for Ready-to-Eat and Stored Products

This study was performed in order to assess technological characteristics, proximate composition, fatty acids profile, and microbiological safety of sous-vide processed salmon in comparison with steaming and roasting. The cooking loss was lower in the sous-vide method (6.3-9.1%) than in conventional methods (11.6-16.2%). The preparation of salmon using sous-vide was more time- and energy-consuming than steaming. The dry matter content of the salmon fillets was higher in conventionally processed samples than sous-vide due to the evaporation of water, and it was connected with total protein (r = 0.85) and lipid content (r = 0.73). Analysis of the fatty acids profile only revealed significant differences in six fatty acids. All of the heat treatment methods ensured microbiological safety with regard to coagulase-positive Staphylococcus, E. coli, Listeria monocytogenes, and Salmonella spp. However, in sous-vide (57 °C, 20 min) and steamed samples after storage Enterobacteriaceae bacteria (<104) was detected. Summing up, high parameters of sous-vide salmon cooking, when considering both technological parameters, nutritional value, and microbiological status should be recommended.

Sous-Vide as a Technique for Preparing Healthy and High-Quality Vegetable and Seafood Products

Sous-vide is a technique of cooking foods in vacuum bags under strictly controlled temperature, offering improved taste, texture and nutritional values along with extended shelf life as compared to the traditional cooking methods. In addition to other constituents, vegetables and seafood represent important sources of phytochemicals. Thus, by applying sous-vide technology, preservation of such foods can be prolonged with almost full retention of native quality. In this way, sous-vide processing meets customers' growing demand for the production of safer and healthier foods. Considering the industrial points of view, sous-vide technology has proven to be an adequate substitute for traditional cooking methods. Therefore, its application in various aspects of food production has been increasingly researched. Although sous-vide cooking of meats and vegetables is well explored, the challenges remain with seafoods due to the large differences in structure and quality of marine organisms. Cephalopods (e.g., squid, octopus, etc.) are of particular interest, as the changes of their muscular physical structure during processing have to be carefully considered. Based on all the above, this study summarizes the literature review on the recent sous-vide application on vegetable and seafood products in view of production of high-quality and safe foodstuffs.

Microbiological Quality of Foodstuffs Sold on Expiry Date at Retail in Portugal: A Preliminary Study

Currently, food waste represents an important issue due to its negative economic, social and environmental impact. To reduce the food waste levels, some retailers’ brands implement discounting based on the proximity to expiry. Since this practice may involve potential food poisoning, a total of 94 food products from animal origin, purchased in two supermarkets in North Portugal on the expiry date, were analyzed for selected foodborne and spoilage microorganisms. Moreover, the samples were classified as satisfactory and not satisfactory according to their microbiological quality. The results showed that none of the samples presented counts for Salmonella spp., S. aureus, B. cereus. L. monocytogenes was detected in one sample over the limit of 2 log cfu/g as defined by Regulation 2073/2005. The evaluation of food hygiene and spoilage indicators showed that the processed foods displayed lower counts than raw products (beef, pork, chicken and fish). Regarding Enterobacteriaceae, raw products presented on average over 2 log cfu/g than processed foods, with the exception of beef samples that accounted over 3 log cfu/g more than processed foods. In addition, E. coli was mainly detected in fresh meat of which chicken and pork displayed the highest counts. Regarding the qualitative classification, 51.06% of the samples were not satisfactory for the total mesophilic counts, while 62.76% and 58.51% displayed positive results for Enterobacteriaceae and molds and yeasts (M&Y) criteria, respectively. In all, 70.21% of the samples analyzed at the expiry date failed, at least, in one microbiological criterion. The results indicate that the foods available at the end of the shelf life in supermarkets do not represent a risk for food poisoning due to the absence of foodborne pathogens. Since the microbiological indicators of storage/handling of raw products were mainly unsatisfactory, this indicates that the sale of these perishable foods at the end of the shelf life may not be recommended. On the other hand, processed products subjected to food conservation procedures (i.e., thermal processing) could be sold at the end of their shelf life or donated beyond the best-before date, due to its physical, chemical and microbiological stability. However, evidences of foodborne outbreaks associated to this kind of foodstuffs indicated the need of a proper risk assessment. Moreover, it is important to remark that other factors such as small sample size, the absence of the evaluation of the handling, and storage conditions along the food chain or organoleptic alterations must be assessed in further studies.

Influence of Citric Acid on the Pink Color and Characteristics of Sous Vide Processed Chicken Breasts During Chill Storage

Chicken breast dipped with citric acid (CA) was treated by sous vide processing and stored in a refrigerated state for 0, 3, 6, 9, and 14 d. A non-dipped control group (CON) and three groups dipped in different concentrations of citric acid concentration were analyzed (0.5%, 0.5CIT; 2.0%, 2CIT and 5.0%, 5CIT; w/v). Cooking yield and moisture content increased due to the citric acid. While the redness of the juice and meat in all groups showed significant increase during storage, the redness of the citric acid groups was reduced compared to the control group (p<0.05). The percentage of myoglobin denaturation (PMD) of the CA groups was also increased according to the level of CA during storage. Total aerobic counts, Enterobacteriaceae counts, volatile basic nitrogen and thiobarbituric acid reactive substances (TBARS) were generally lower in the citric acid-treated samples than in untreated ones, indicating extended shelf life of the cooked chicken breast dipped in citric acid solution. The shear force of the 2CIT and 5CIT groups was significantly lower (p<0.05). The findings indicated positive effects in the physicochemical properties and storage ability of sous vide chicken breast at 2% and 5% citric acid concentrations.

Nutritional quality of sous vide cooked carrots and brussels sprouts

Phytochemicals (carotenoids, phenolic compounds, and ascorbic acid) and antioxidant capacity (measured by TEAC, FRAP, and TRAP assays) were evaluated on carrots and Brussels sprouts sous vide processed and then stored refrigerated for 1, 5, and 10 days and compared with the corresponding raw and oven-steamed products. Data showed that sous vide cooked carrots had higher amounts of carotenoids, phenolic compounds, and ascorbic acid than steamed products, and only a slight decrease of phenolic compounds was recorded during sous vide storage. Contrasting results were obtained on sous vide processed Brussels sprouts: higher carotenoid amounts and TEAC and TRAP values and lower phenolic compounds, ascorbic acid, and FRAP values were exhibited by sous vide in comparison with steamed samples. Phytochemicals and TAC also decreased during Brussels sprout sous vide storage with the exception of carotenoids. The results of this study demonstrated that sous vide preparation can preserve and/or enhance the nutritional quality of carrots, which remain a good source of carotenoids also after long refrigerated storage, whereas the same treatment could be recommended as an alternative to oven-steaming in the preparation of Brussels sprouts for short-term maintenance to avoid a large ascorbic acid depletion.