The major strategies for designing surfaces that prevent fouling due to proteins, bacteria, and marine organisms are reviewed. Biofouling is of great concern in numerous applications ranging from biosensors to biomedical implants and devices, and from food packaging to industrial and marine equipment. The two major approaches to combat surface fouling are based on either preventing biofoulants from attaching or degrading them. One of the key strategies for imparting adhesion resistance involves the functionalization of surfaces with poly(ethylene glycol) (PEG) or oligo(ethylene glycol). Several alternatives to PEG-based coatings have also been designed over the past decade. While protein-resistant coatings may also resist bacterial attachment and subsequent biofilm formation, in order to overcome the fouling-mediated risk of bacterial infection it is highly desirable to design coatings that are bactericidal. Traditional techniques involve the design of coatings that release biocidal agents, including antibiotics, quaternary ammonium salts (QAS), and silver, into the surrounding aqueous environment. However, the emergence of antibiotic- and silver-resistant pathogenic strains has necessitated the development of alternative strategies. Therefore, other techniques based on the use of polycations, enzymes, nanomaterials, and photoactive agents are being investigated. With regard to marine antifouling coatings, restrictions on the use of biocide-releasing coatings have made the generation of nontoxic antifouling surfaces more important. While considerable progress has been made in the design of antifouling coatings, ongoing research in this area should result in the development of even better antifouling materials in the future.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/adma.201001215

Antifouling coatings: recent developments in the design of surfaces that prevent fouling by proteins, bacteria, and marine organisms.

Polymer surface modification for the attachment of bioactive compounds

Perspectives for chitosan based antimicrobial films in food applications

https://ciptaindomedica.files.wordpress.com/2011/01/antimicrobial-herb-and-spice-compounds-in-food.pdf

Antimicrobial herb and spice compounds in food.

Antioxidant activity has been assessed in many ways. The limitation of many newer methods is the frequent lack of an actual substrate in the procedure. The combination of all approaches with the many test methods available explains the large variety of ways in which results of antioxidant testing are reported. The measurement of antioxidant activities, especially of antioxidants that are mixtures, multifunctional or are acting in complex multiphase systems, cannot be evaluated satisfactorily by a simple antioxidant test without due regard to the many variables influencing the results. Several test procedures may be required to evaluate such antioxidant activities. A general method of reporting antioxidant activity independent of the test procedure is proposed.

http://ucce.ucdavis.edu/files/datastore/608-46.pdf

Methods for testing antioxidant activity

Modeling microbial growth.

The microbiological quality of different types of table olives was evaluated; artisan products and those produced by small and middle-sized companies were compared and the microbial population of the three types of table olives was characterized. The results indicated that the artisan olives were characterized by an acceptable hygienic quality. The industrial products, when thermally untreated, showed mesophilic bacteria, lactic acid bacteria and yeast cell loads similar to those of the artisan products, whereas total and fecal coliforms and staphylococci presented lower counts. The thermally untreated products were characterized by a higher heterogeneity in the yeast and bacteria population. Halotolerant yeasts, Hansenula anomala, Zygosaccharomyces rouxii, Hansenula subpelliculosa and Pichia membranaefaciens, were identified with different frequencies according to the product typology.

Microbial characterization of table olives from the Apulian market

This research proposes the optimization of a preserving treatment (homogenization—high-pressure homogenization (HPH)—and some safe antimicrobial compounds) able to inhibit the spoiling and pathogenic microflora of milk. In the first phase, 16 strains, including lactobacilli and bifidobacteria, pseudomonads and enterobacteria, were studied in order to assess their resistance to homogenization (pressure ranging from 50 to 150 MPa for single-step treatments; multi-step treatments were performed at 150 MPa through two or three passes across the homogenizing valve). Lactobacilli and bifidobacteria were the most resistant microorganisms (as a threefold treatment at 150 MPa was required to achieve a cell reduction of 1–2 log cfu/ml), followed by pathogens and then by pseudomonas and enterobacteria. Then, a mixture design was further used to define combinations of homogenization (0–150 MPa pass−1), vanillic acid (0–0.24 %) and citrus extract (0–300 ppm), to control the growth of a mixture of pseudomonas, enterobacteria and lactic acid bacteria; results were used to build two successive models: a primary model for the estimation of the physiological parameters of the microorganisms, whose fitting parameters were used to build a secondary model (polynomial equation) to predict the effectiveness of the combinations of HPH, citrus extract and vanillic acid. Statistical analysis highlighted that a prolongation of shelf life by 4 days (evaluated by pseudomonas cell counts) could be achieved combining homogenization at 75 MPa with either 0.12 % of vanillic acid or 150 ppm of citrus extract.

Combination of Homogenization, Citrus Extract and Vanillic Acid for the Inhibition of Some Spoiling and Pathogenic Bacteria Representative of Dairy Microflora

The topic of this paper is the investigation of the antibacterial effect of ultrasound (US) towards Salmonella enterica in a rice beverage. The beverage was inoculated at different levels (8 and 5 log CFU/mL) and US-treated; then, a challenge test under refrigeration was carried out. The maximum net power of the equipment was 130 W; the treatment was carried out at 40–100% of the net power, for 2–10 min; the pulse was set to 2–10 s. For both the inoculum levels, power and time were the most important factors for the antimicrobial effect towards S. enterica. The combinations resulting in the highest inactivation of the pathogen were tested during the challenge test at 4 °C, and in some combinations, S. enterica remained below the detection limit for 13 days.

Inactivation of Salmonella enterica in a Rice Beverage by Ultrasound: Study of the Parameters Affecting the Antibacterial Effect

This paper reports on the investigation of the use of citrus extract (0–3 ppm), sodium benzoate (0–300 ppm) and pressure homogenisation (PH) (0–90 MPa) against Pichia membranifaciens The centroid approach was used to combine the three variables and point out their individual and interactive effects The assays were performed in a laboratory medium (YPD broth), and the samples were stored at 25 °C for 6 days; the viable count of P membranifaciens was evaluated, and the data were modelled through the Gompertz equation, to assess the reduction of the initial contamination just after the homogenisation (R
 N
 ) and the prolongation of the lag phase (I
 λ
 ) The results of this paper suggested that citrus extract could be a suitable alternative for the inhibition of P membranifaciens in acidic drinks, as a low amount of this compound (3 ppm) increased the lag phase by 60–70% In addition, homogenisation (90 MPa) was able to reduce significantly the initial cell number

Milena Sinigaglia

Papers

Modeling microbial growth.

Microbial characterization of table olives from the Apulian market

Combination of Homogenization, Citrus Extract and Vanillic Acid for the Inhibition of Some Spoiling and Pathogenic Bacteria Representative of Dairy Microflora

Inactivation of Salmonella enterica in a Rice Beverage by Ultrasound: Study of the Parameters Affecting the Antibacterial Effect

Inhibition of Pichia membranifaciens by Homogenisation and Antimicrobials