Nature-Identical Compounds and Organic Acids Ameliorate and Prevent the Damages Induced by an Inflammatory Challenge in Caco-2 Cell Culture.

Bioactive compounds, such as organic acids (OA) and nature-identical compounds (NIC), can exert a role in the protection of intestinal mucosa functionality due to their biological properties. The aim of this study was to understand the role of 2 OA (citric and sorbic acid) and 2 NIC (thymol and vanillin), alone or combined in a blend (OA + NIC), on intestinal barrier functionality, either during homeostatic condition or during an inflammatory challenge performed with pro-inflammatory cytokines and lipopolysaccharides (LPS). The study was performed on the human epithelial cell line Caco-2, a well-known model of the intestinal epithelial barrier. The results showed how OA and NIC alone can improve transepithelial electrical resistance (TEER) and mRNA levels of tight junction (TJ) components, but OA + NIC showed stronger efficacy compared to the single molecules. When an inflammatory challenge occurred, OA + NIC blend was able both to ameliorate, and prevent, damage caused by the pro-inflammatory stimulus, reducing or preventing the drop in TEER and improving the TJ mRNA expression. The data support the role of OA + NIC in modulating gut barrier functionality and reducing the negative effects of inflammation in intestinal epithelial cells, thereby supporting the gut barrier functionality.

Efficacy of some feed additives to attenuate the hepato-renal damage induced by aflatoxin B1 in rabbits.

The present trial was conducted to evaluate the beneficial role of some feed additives (potassium sorbate; Sor, hydrated sodium calcium almuniosilicate; Hsc and l-methionine; L-M) in attenuating the hepatic and renal toxicity of aflatoxin B1 (AFB1) in rabbits. A total number of 72 NZW growing rabbits (5 week-old) were divided into six experimental groups (four replicates with three rabbits each) as follows: control group, AFB1 group (supplemented with AFB1 0.3 mg/kg diet), AFB1 + Sor group (AFB1 0.3 mg/kg diet + Sor 2 g/kg diet), AFB1 + Hsc group (AFB1 0.3 mg/kg diet + Hsc 5 g/kg diet), AFB1 + L-M group (AFB1 0.3 mg/kg diet + L-M 8 g/kg diet) and AFB1 + Mix group (AFB1 0.3 mg/kg diet + 2 Sor + 5 Hsc + 8 L-M g/kg diet). Serum levels of total protein, albumin and globulin were significantly reduced by AF. AF increased the serum activity of aspartate aminotransferase (AST), alanine amino transferase (ALT) and alkaline phosphatase (ALP) enzymes. While, they were reduced in AF + Sor and AF + Mix groups compared with AF group. AF increased the level of cystatin C and Beta-2 microglobulin (BMG). All other supplements significantly reduced the level of cystatin C than AF; however, this reduction was more pronounced in AF-L-M group. AF + Sor, AF + L-M and AF + Mix equally reduced the BMG level than AF and AF + HSc, however, still higher than control. AF elevated the total cholesterol (TC) and LDL-cholesterol levels. A significant reduction in HDL cholesterol was seen in AF group. Additionally, AF induced pathological alterations in the liver and kidney of exposed rabbits on the other hands, the three additives separately or in mix attenuated the Af-induced alterations. In conclusion, the dietary supplementation of Sor, L-M, Hsc or their mixture was effective in ameliorating the negative effects of AFB1 on liver and kidney function and structure in rabbits with more better improvement obtained by Sor or L-M separately.

Larvicidal activity of piperovatine and dichloromethane extract from Piper corcovadensis roots against mosquitoes Aedes aegypti L / Actividad larvicida de piperovatina y extracto de diclorometano de las raíces de Piper corcovadensis contra mosquitos vectores del dengue Aedes aegypti L

The research of new substances capable of controlling the Aedes aegypti mosquito is urgent due to the increase in the transmission of the diseases such as dengue, chikungunya and Zika virus by the vector. Thus, the aim of this study was to evaluate the larvicidal activity of crude extract of Piper corcovadensis roots, a native plant from Brazil, and of the isolated compound piperovatine against larvae of A. aegypti by the larval immersion test. The lethal concentration that killed 50% (LC50) and 99% (LC99) of larvae was determined by Probit analysis. The results indicated high larvicidal activity on A. aegypti larvae for crude extract of Piper corcovadensis roots with LC50 of 4.86 µg/mL and LC99 of 15.50 µg/mL and piperovatine with LC50 of 17.78 µg/mL and LC99 of 48.55 µg/mL. This work opens new perspectives to the development of future products with crude extract of Piper corcovadensis roots and piperovatine that can be applied to mosquito control.

La investigación de nuevas sustancias capaces de controlar el mosquito Aedes aegypti es urgente debido al aumento en la transmisión de enfermedades como el dengue, el chikungunya y el virus Zika por el vector. Por lo tanto, el objetivo de este estudio fue evaluar la actividad larvicida del extracto crudo de las raíces de Piper corcovadensis, una planta nativa de Brasil, y del compuesto aislado piperovatine contra larvas de A. aegypti mediante la prueba de inmersión larvaria. La concentración letal que mató al 50% (LC50) y al 99% (LC99) de larvas se determinó mediante análisis Probit. Los resultados indicaron una alta actividad larvicida en larvas de A. aegypti para extracto crudo de las raíces de Piper corcovadensis con LC50 de 4.86 µg/mL y LC99 de 15.50 µg/mL y piperovatine con LC50 de 17.78 µg/mL y LC99 de 48.55 µg/mL. Este trabajo abre nuevas perspectivas para el desarrollo de futuros productos con extracto crudo de las raíces de Piper corcovadensis y piperovatine que pueden aplicarse al control de mosquitos.

Dietary supplementation of potassium sorbate, hydrated sodium calcium almuniosilicate and methionine enhances growth, antioxidant status and immunity in growing rabbits exposed to aflatoxin B1 in the diet.

The present experiment was conducted to evaluate the effect of dietary supplementation with some feed additives (potassium sorbate; Sor, hydrated sodium calcium almuniosilicate; Hsc and L-methionine; L-M) against aflatoxin B1 (AF) toxicity in rabbits. A total of 72 growing rabbits (5-week-old) were distributed into six equal groups (4 replicates with 3 rabbits each). The experimental groups are as follows: control group, AF group (supplemented with AF 0.3 mg/kg diet), AF + Sor group (AF 0.3 mg/kg diet + Sor 2 g/kg diet), AF + Hsc group (AF 0.3 mg/kg diet + Hsc 5 g/kg diet), AF + L-M group (AF 0.3 mg/kg diet + L-M 8 g/kg diet) and AF + Mix group (AF 0.3 mg/kg diet + 2 Sor + 5 Hsc + 8 L-M g/kg diet). Live body weight and weight gain at 13 weeks of age were significantly reduced by AF. Feed intake at 13 weeks of age was decreased in AF, AF + Hsc and AF + Mix compared to the control. AF, AF + Hsc and AF + Mix showed the lowest total antioxidant capacity compared to the control. The highest level of reactive oxygen species and 8-Hydroxy-2-desoxyguanosine was observed in AF group. Using of other supplements with AF increased immunoglobulinM than AF alone. In conclusion, dietary supplementation of Sor, L-M, Hsc or their mixture was effective in reducing the adverse effects of AF on performance, antioxidant and immune status of rabbits with more better improvement obtained by Sor or L-M separately.

Synergistic Effects of The Enhancements to Mitochondrial ROS, p53 Activation and Apoptosis Generated by Aspartame and Potassium Sorbate in HepG2 Cells.

The safety of food additives has been widely concerned. Using single additives in the provisions of scope is safe, but the combination of additives, may induce additive, synergy, antagonism and other joint effects. This study investigated the cytotoxicity of aspartame (AT) together with potassium sorbate (PS). Thiazolyl Blue Tetrazolium Bromide (MTT) assay indicated that AT and PS had IC50 values of 0.48 g/L and 1.25 g/L at 24 h, respectively. High content analysis (HCA) showed that both AT and PS had a negative effect on mitochondrial membrane potential (MMP), reactive oxygen species (ROS) and DNA damage while the joint group behaved more obviously. The biochemical assays revealed typical cell morphological changes and the activation of cytochrome c and caspase-3 verified apoptosis induced by AT together with PS. With dissipation of MMP and increase of cell membrane permeability (CMP), it indicated AT together with PS-induced apoptosis was mediated by mitochondrial pathway. Meanwhile, p53 were involved in DNA damage, and the ratio of Bax/Bcl-2 was increased. Moreover, excessive ROS induced by AT together with PS is a key initiating factor for apoptosis. All these results proved that p53 was involved in apoptosis via mitochondria-mediated pathway and the process was regulated by ROS.

Mode of action of piperovatine, an insecticidal piperamide isolated from Piper piscatorum (Piperaceae), against voltage-gated sodium channels.

Piperamides, which are secondary metabolites in the genus Piper, have potent insecticidal activity, and have thus inspired the development of novel insecticides. In this study, piperovatine, a piperamide from Piper piscatorum (Piperaceae), was investigated using a two-electrode voltage clamp to clarify its detailed mode of action against voltage-gated sodium channels, a classic target. In Xenopus oocytes expressing voltage-gated sodium channels from German cockroach (Blattella germanica), piperovatine induced inward currents depending on repetitive openings. For instance, maximal currents were generated with 10 µM piperovatine following 100 trains of depolarizing pulses with frequency 25 Hz. Piperovatine also shifted the half-activation voltage after conditioning pulses from -35 mV to -45 mV. In addition, piperovatine-modified currents were correlated with not only the number of prior conditioning pulses but also the proportion of activated channels. Finally, piperovatine was found to stabilize voltage-gated sodium channels in the fast-inactivated state after opening, and inhibit transition to the slow-inactivated state. These results suggest that piperovatine preferably binds to activated channels and stabilizes voltage sensors at the conformation acquired during depolarization.

Alternatives to carcinogenic preservatives in Chinese Sausage - Sorbic acid-loaded chitosan/tripolyphosphate nanoparticles.

Preservatives in processed meat raise significant concerns associated with bowel cancer and diabetes, and implicate various public health issues. This introduces the need for safer preservatives to uphold public health standards. However, developing safer alternatives to these preservatives poses a significant challenge to food industry. A potential solution to this issue is the use of loaded nanoparticles as preservative agents. This study investigated antimicrobial and antioxidant effects of sorbic acid-loaded chitosan/tripolyphosphate nanoparticles (SAN) in Chinese Sausage. SAN were prepared through ionic gelation, followed by natural air-drying for 20 days. After preparation, the antimicrobial and antioxidant activities of various treatment groups were analyzed intermittently during storage at room temperature. SAN-treated samples had significantly lower levels of surviving bacteria, molds, and yeasts than the blank control (p < 0.05) over the entire 72 days of storage. Additionally the SAN-treated samples also had lower levels of surviving bacteria than the chitosan/tripolyphosphate samples after 31-56 days of storage (p < 0.05). The thiobarbituric acid value and pH of the SAN-treated samples were also significantly lower than the blank control (p < 0.05). These results indicated that SAN could be a good intervention strategy to retard lipid oxidation and inhibit microbial growth in Chinese Sausage.

Effect of potassium sorbate (E-202) and the antifungal PgAFP protein on Aspergillus carbonarius growth and ochratoxin A production in raisin simulating media.

BACKGROUND: Ochratoxin A (OTA) is a mycotoxin produced by several species of Aspergillus and Penicillium fungi. The presence of OTA in raisins is mainly related to black Aspergillus spp. contamination. This toxin poses risks to human and animal health due to its high toxicity and carcinogenicity. New strategies to avoid the risk associated with OTA are therefore necessary. RESULTS: A comparison was made between the effects of the antifungal protein PgAFP and potassium sorbate (E-202) on the growth of Aspergillus carbonarius, biosynthetic- and stress-related gene expression and its OTA production at two water activity (aw ) levels, 0.95 and 0.93 aw . The results showed that PgAFP successfully controlled OTA production, whereas E-202, despite being able to reduce Aspergillus carbonarius growth, caused a significant increase in OTA production by the fungus. CONCLUSION: PgAFP protein, a biological compound with an antifungal activity, is safer to use than E-202 and may be proposed as a food preservative and a useful strategy to control ochratoxigenic A. carbonarius in raisins. © 2018 Society of Chemical Industry.

Effects of Sorbic Acid-Chitosan Microcapsules as Antimicrobial Agent on the Properties of Ethylene Vinyl Alcohol Copolymer Film for Food Packaging.

This paper discusses the possibility of using sorbic acid-chitosan microcapsules (S-MPs) as an antibacterial component of active ethylene vinyl alcohol copolymer (EVOH) film. S-MPs with a diameter of approximately 1 to 4 µm showed a sorbic acid loading capacity of 46.5%. Addition of S-MPs (3%, w/w) increased the tensile strength, haze, oxygen, and water vapor barrier properties, as well as reduced the elongations at break and transmittance of S-MPs-EVOH (S-MP-EVOH) film. Antibacterial tests showed that the inhibitory capacity of S-MP-EVOH film against Salmonella Enteritidis and Escherichia coli was higher than that against Listeria monocytogenes. Moreover, the antibacterial effect of sorbic acid-EVOH (S-EVOH) film was stronger than that of S-MP-EVOH film. However, S-MP-EVOH film demonstrated a longer effective time than S-EVOH film. Using the total viable counts and total volatile base nitrogen as the judgment standard, S-MP-EVOH/polyethylene terephthalate (PET) composite film could extend the shelf life of fish fillets by 4 d at 4 °C, compared with EVOH/PET film. For this reason, S-MP could be a potential antibacterial component of active films.

Food additives: Sodium benzoate, potassium sorbate, azorubine, and tartrazine modify the expression of NFκB, GADD45α, and MAPK8 genes.

It has been reported that some of the food additives may cause sensitization, inflammation of tissues, and potentially risk factors in the development of several chronic diseases. Thus, we hypothesized that expressions of common inflammatory molecules - known to be involved in the development of various inflammatory conditions and cancers - are affected by these food additives. We investigated the effects of commonly used food preservatives and artificial food colorants based on the expressions of NFκB, GADD45α, and MAPK8 (JNK1) from the tissues of liver. RNA was isolated based on Trizol protocol and the activation levels were compared between the treated and the control groups. Tartrazine alone could elicit effects on the expressions of NFκB (p = 0.013) and MAPK8 (p = 0.022). Azorubine also resulted in apoptosis according to MAPK8 expression (p = 0.009). Preservatives were anti-apoptotic in high dose. Sodium benzoate (from low to high doses) dose-dependently silenced MAPK8 expression (p = 0.004 to p = 0.002). Addition of the two preservatives together elicited significantly greater expression of MAPK8 at half-fold dose (p = 0.002) and at fivefold dose (p = 0.008). This study suggests that some of the food preservatives and colorants can contribute to the activation of inflammatory pathways.

Distinct effects of sorbic acid and acetic acid on the electrophysiology and metabolism of Bacillus subtilis.

Sorbic acid and acetic acid are among the weak organic acid preservatives most commonly used to improve the microbiological stability of foods. They have similar pKa values, but sorbic acid is a far more potent preservative. Weak organic acids are most effective at low pH. Under these circumstances, they are assumed to diffuse across the membrane as neutral undissociated acids. We show here that the level of initial intracellular acidification depends on the concentration of undissociated acid and less on the nature of the acid. Recovery of the internal pH depends on the presence of an energy source, but acidification of the cytosol causes a decrease in glucose flux. Furthermore, sorbic acid is a more potent uncoupler of the membrane potential than acetic acid. Together these effects may also slow the rate of ATP synthesis significantly and may thus (partially) explain sorbic acid's effectiveness.

The effect of topical corticosteroids, topical antihistamines, and preservatives on human ciliary beat frequency.

BACKGROUND: The aim of this study was to investigate the effect of the corticosteroids, the antihistamines, and the preservatives benzalkonium chloride (BKC) and potassium sorbate (PS) in intranasal medications on human nasal epithelial ciliary beat frequency (CBF). METHODS: Primary ciliated epithelial cell cultures from the human nasal mucosa of chronic sinusitis patients were established. Changes in CBF of epithelial cell cultures treated/untreated with intranasal medications or preservatives were assessed using high-speed digital imaging methods. RESULTS: Budesonide caused a rapid but reversible ciliostasis and showed no ciliotoxic effect at 10% dilution. Fluticasone propionate induced an irreversible ciliostatic activity and showed a reversible decrease in CBF at 10% dilution. Azelastine hydrochloride and levocabastine hydrochloride both induced a dose-dependent and irreversible decrease in CBF, although the ciliotoxic effect was not evident at 5% dilution. BKC resulted in an irreversible ciliostasis at 0.005 or 0.01% concentrations, whereas PS did not show any change in CBF at 0.12 or 0.24% concentrations. CONCLUSIONS: Crystalline BKC and BKC-containing intranasal medications, including fluticasone propionate, azelastine hydrochloride and levocabastine hydrochloride, but not PS or PS-containing intranasal budesonide spray, led to irreversible ciliostasis in human nasal epithelial cell cultures when applied at clinically relevant concentrations.

Plasma treated polyethylene terephthalate/polypropylene films assembled with chitosan and various preservatives for antimicrobial food packaging.

In this study, polyethylene terephthalate/polypropylene (PET/PP) films were treated via atmospheric pressure plasma, assembled with chitosan and various preservatives and applied for antimicrobial food packaging. Surface properties of these obtained films were studied by contact angle measurement, atomic force microscopy (ATM), X-ray photoelectron spectroscopy (XPS), Fourier transformed infrared spectroscopy (FT-IR) and dynamic laser scattering (DLS). The above results showed that the surface hydrophilicity and roughness of the films increased after the plasma treatment. Besides, chitosan and the preservatives were successfully assembled onto the surface of the films. In addition, the antimicrobial activities of the films against three kinds of microorganisms (Staphylococcus aureus, Bacillus subtilis and Escherichia coli) were investigated and the results indicated that the inhibition ratios against B. subtilis and E. coli reached almost 100% while the inhibition ratios against S. aureus were lower than 85%. Moreover, the accumulative release profiles of the antimicrobial substances migrating from the assembled films into the release solutions revealed that their release speed increased with the increment of temperature and acidity, but decreased with enhancing the ionic strength regulated by sodium chloride or with lowering the ionic mobility regulated by sucrose.

Weak-acid preservatives: pH and proton movements in the yeast Saccharomyces cerevisiae.

Weak-acid preservatives commonly used to prevent fungal spoilage of low pH foods include sorbic and acetic acids. The "classical weak-acid theory" proposes that weak acids inhibit spoilage organisms by diffusion of undissociated acids through the membrane, dissociation within the cell to protons and anions, and consequent acidification of the cytoplasm. Results from 25 strains of Saccharomyces cerevisiae confirmed inhibition by acetic acid at a molar concentration 42 times higher than sorbic acid, in contradiction of the weak-acid theory where all acids of equal pK(a) should inhibit at equimolar concentrations. Flow cytometry showed that the intracellular pH fell to pH 4.7 at the growth-inhibitory concentration of acetic acid, whereas at the inhibitory concentration of sorbic acid, the pH only fell to pH 6.3. The plasma membrane H⁺-ATPase proton pump (Pma1p) was strongly inhibited by sorbic acid at the growth-inhibitory concentration, but was stimulated by acetic acid. The H⁺-ATPase was also inhibited by lower sorbic acid concentrations, but later showed recovery and elevated activity if the sorbic acid was removed. Levels of PMA1 transcripts increased briefly following sorbic acid addition, but soon returned to normal levels. It was concluded that acetic acid inhibition of S. cerevisiae was due to intracellular acidification, in accord with the "classical weak-acid theory". Sorbic acid, however, appeared to be a membrane-active antimicrobial compound, with the plasma membrane H⁺-ATPase proton pump being a primary target of inhibition. Understanding the mechanism of action of sorbic acid will hopefully lead to improved methods of food preservation.

C-terminal trans,trans-muconic acid ethyl ester partial retro-inverso pseudopeptides as proteasome inhibitors.

The development of specific inhibitors of the proteasome represents an important opportunity for new drug therapies. The central role of the multicatalytic complex in the intracellular proteolysis mediated by ubiquitin-proteasome pathway goes to discovery many molecules able to selectively inhibits enzymatic active subsites. Now, we report synthesis and activity of a new partial retro-inverso oligopseudopeptide derivatives bearing a trans,trans-muconic acid ethyl ester pharmacophoric unit at the C-terminal. Some analogues selectively inhibited in µM range the caspase-like (C-L) activity in the ß1 subunit of the proteasome.

Ultrasound application for the control of decay on apple at different stage of ripening.

Ultrasonic technology is known for many years and is used for several purposes such as sonochemistry, extraction of natural compounds, degassing of solvent, inactivation of enzymes and microorganism. In postharvest ultrasound is applied in not destructive analysis of crop for the determination of the maturation stage. Until now, however, the potential of the sonication as a physical mean for not conventional postharvest treatment of fresh fruit has been little investigated. Here we report on the results obtained with apple fruit (Malus domestica Borkh. cv San Giovanni, from Sardinian germplasm) dipped in a solution of potassium sorbate with or without sonication. Treatment was carried out with an ultrasonic processor (1500 W, 20Khz) connected to a 25 mm phi probe immersed in 10 L of deionized water placed in a steel vessel. Fruit at different ripening stages, inoculated or not inoculated with Penicillium expansum, was sonicated before or after the inoculation. Following the treatment, fruit was left to dry, put into boxes and cold-stored. Results showed that ultrasound alone enhanced the natural resistance of ripe fruit when inoculated after sonication. No effect was observed when the ultrasound application was carried out after inoculation with P. expansum on un-ripe or ripe apples. Potassium sorbate showed to be ineffective in controlling the decay regardless of the ripening stage and the time of inoculation. On the contrary, a significant enhance in decay control was observed when the application of potassium sorbate was performed in the presence of ultrasound.

Alternative methods to control postharvest decay caused by Penicillium expansum in plums (Prunus domestica L.).

In the latest years, investigation on postharvest treatments has been increasingly addressed to preserve human health and environment safeguard. Several preservative compounds, physical treatments and biological control agents to restrain postharvest pathogens on horticultural products have been widely studied. Among them potassium sorbate (KS) has been generally recognized as safe for use in foods and personal care products. It acts as microbial growth inhibitor and fungistatic agent in foods, including vegetable and fruit products. The efficacy of KS, used alone or combined with heat treatments or biocontrol agents, has been demonstrated in Citrus and stone fruits. Here we report the results of 3 experiments aimed at controlling Penicillium expansum Link decay with the use of KS on a yellow ('Shiro') and a red ('Sanguigna di Bosa II', from the Sardinian germplasm) plum cultivar. An integrated approach, combining ultrasounds (US) as a physical mean and KS solutions at different concentrations, has been employed. In the first experiment, 360 fruits were wounded twice and divided into 6 sets (6 x 60), three of which were inoculated with an isolate of P. expansum (20 microl of a 10(5) cfu x mL(-1)). Then, 180 fruit (half inoculated) were treated by pipetting into each wound 20 microl of a KS solution containing 0, 1.5 or 3% (w/v), respectively. In exp. 2, all fruit (number) was wounded and inoculated, and after 24 h treated by immersion (1 min) into solutions containing 0, 1.5 or 3% (w/v) of SK, with or without the use of US. In exp. 3, wounded fruits were treated by immersion or sonication like in exp. 2, while inoculation took place after 24 h. Then, plums were kept at 25 degrees C and 75-80% RH and the infection degree was monitored after 3 and 6 days. In both cultivars, the 1.5% KS solution significantly reduced the natural infection, while the 3% KS solution resulted effective only on the red one. Moreover, the 1.5% solution was effective in controlling decay of artificially inoculated fruit, achieving a 56% reduction compared to control. Similar results were attained in exp. 2 and 3, where the combination of salt and sonication improved the efficacy, likely by increasing the salt diffusion into the wounds.

Effects of antimicrobial coating from catfish skin gelatin on quality and shelf life of fresh white shrimp (Penaeus vannamei).

UNLABELLED: The present study was conducted to evaluate the effect of fish skin gelatin-based antimicrobial coating on the shelf life of fresh white shrimp (Penaeus vannamei). Antimicrobial coating was prepared by incorporating potassium sorbate, sodium tripolyphosphate, or both ingredients in coating solution made from catfish skin gelatin. Shrimp samples were untreated, rinsed with water, or coated with the antimicrobial films, and then they were stored in ice under aerobic conditions. Samples were taken periodically and evaluated for total aerobic plate count, psychrotrophic bacteria count, near-infrared spectrum (NIR), springiness, pH value, and color measurement. The results showed that the antimicrobial coating could retard microbial growth and prolong shelf life for up to 10 d. Partial least square analysis produced an acceptable model fitting between the NIR and the changes of microbial count in shrimp samples. The springiness and pH value of shrimp muscle were not affected by the coating treatments. Color parameter a* value increased linearly for all the treatments during the whole ice-storage period. PRACTICAL APPLICATION: One of the most important technical and economic problems facing the shrimp industry is the relatively short shelf life of fresh shrimp products. Catfish skin gelatin-based antibacterial edible films/coatings provide an ideal technique to solve this problem. The shrimp industry will be the immediate beneficiary of the study, and the information provided by this research will be expended to other seafood.

Bactericidal synergism through enterocin AS-48 and chemical preservatives against Staphylococcus aureus.

AIMS: To determine the effectiveness of enterocin AS-48 on Staphylococcus aureus CECT 976 in combination with chemical preservatives at acidic and neutral pH. METHODS AND RESULTS: At pH 4.5, the activity of AS-48 increases in the presence of lactic acid (1.0%), acetic acid (0.5% and 1.0%), and citric acid (0.3% and 0.6%). This synergistic effect has also been observed during the first 8 h of incubation with benzoate (0.06% and 0.12%) and sorbate (2% and 3%). Interestingly, at pH 7, lactate (1%) increases the inhibitory effect of AS-48, reducing the S. aureus population by 6 log units compared with the control culture. At neutral pH, combinations of AS-48 and sodium tripolyphosphate, STPP (0.3% and 0.5%) also eliminate this pathogen after 24 h. CONCLUSIONS: These results indicate that enterocin AS-48 could be applied in combination with a range of chemical preservatives in order to increase its efficacy in inhibiting S. aureus. SIGNIFICANCE AND IMPACT OF THE STUDY: This study supports the potential use of enterocin AS-48 as a biopreservative to control S. aureus in combination with other food-grade chemical hurdles.

Organic acid and formaldehyde treatment of animal feeds to control Salmonella: efficacy and masking during culture.

AIMS: To investigate whether treatment of animals feeds with organic acids/formaldehyde may mask the presence of Salmonella, when assessed by standard cultural methods. METHODS AND RESULTS: Four commercial treatments were applied at the manufacturers' recommended rates on feeds artificially inoculated with Salmonella. The recovery of Salmonella from these treated feeds was assessed after specific antagonists were added to the treatments during culture. A control group of treated feed received no antagonist. Masking of Salmonella was demonstrated when the addition of antagonists resulted in recovery of Salmonella from the treated feed, compared with a negative recovery when no antagonists were added. There were large variations in the efficacy of treatments, and masking was demonstrated with all four tested treatments. One formaldehyde-based product showed greater efficacy and less masking. Masking was greater when high levels of Salmonella were present in the feed. CONCLUSIONS: Some organic acid or formaldehyde-based feed treatments may mask the presence of Salmonella. SIGNIFICANCE AND IMPACT OF THE STUDY: Feeds may be deemed safe despite being contaminated with Salmonella. The use of antagonists during culture may help assess the level of Salmonella contamination when organic acid or formaldehyde treatments have been applied to feed ingredients.