Combination of garlic essential oil, allyl isothiocyanate, and nisin Z as bio-preservatives in fresh sausage.

The effects of natural antimicrobial compounds (garlic essential oil [GO], allyl isothiocyanate [AITC], and nisin Z [NI]) on microbiological, physicochemical and sensory characteristics of fresh sausage were assessed. The minimum inhibitory concentrations (MICs) and the minimum bactericidal concentrations (MBCs) towards Escherichia coli O157:H7 and Lactobacillus plantarum were determined in vitro. Sausages inoculated with E. coli O157:H7, were treated with different combinations of antimicrobials and assessed for microbiological and physicochemical parameters during storage (6C for 20 d). Treatments that presented the greatest antimicrobial effects were subjected to sensory evaluation. Combinations of 20 mg/kg NI + 125 µL/kg GO + 62.5 µL/kg AITC or 20 mg/kg NI + 62.5 µL/kg GO + 125 µL/kg AITC were effective in reducing E. coli O157H7 and spoilage lactic acid bacteria, and maintained the physicochemical characteristics of fresh sausage. Combinations of NI, GO and AITC were effective to improve the safety and the shelf life of fresh sausage, with no impact on its sensory acceptance.

The physiological response of broiler chickens to the dietary supplementation of the bacteriocin nisin and ionophore coccidiostats.

The aim of this study was to investigate the effect of dietary supplementation with nisin alone or in combination with salinomycin or monensin on broiler chickens in terms of growth performance, selected blood parameters, digestive enzyme activity, apparent nutrient digestibility, and tibiotarsus mineralization, as well as selected gastrointestinal tract (GIT) organ weights, intestinal length, and central immune organ weights. Two independent experiments, each including 400 one-day-old female Ross 308 chicks differing in ionophore coccidiostats, i.e., salinomycin and monensin supplementation, were conducted. The following treatments were applied: experiment 1: NA-no additives, SAL-salinomycin (60 mg/kg diet), NIS-nisin (2,700 IU/kg diet), SAL+NIS-salinomycin (60 mg/kg diet) and nisin (2,700 IU/kg diet); experiment 2: NA-no additives, MON-monensin (100 mg/kg diet), NIS-nisin (2,700 IU/kg diet) and MON+NIS-monensin (100 mg/kg diet) and nisin (2,700 IU/kg diet). The addition of nisin with or without ionophores to the birds' diet improved broiler growth performance in terms of BWG and FCR (days 1 to 14) and BWG and FI (15 to 35 d; 1 to 35 d). Salinomycin showed effects similar to those of nisin influence on growth performance (1 to 35 d), while monensin supplementation resulted in lower BWG. Moreover, no additive effect between nisin and ionophores was observed. Nisin and salinomycin had no influence on the serum concentration of selected hormones and other blood biochemical parameters except glucose, which was reduced by nisin. A decrease in lipase activity was observed during nisin and salinomycin supplementation, while the apparent ileal digestibility of fat was not affected. However, the digestibility of crude protein increased with nisin administration. Additionally, the effects of nisin on decreasing the weight and length of GIT segments were observed. Supplementation with nisin and monensin was not associated with a negative impact on tibiotarsus mineralization and the immune organ index. This study suggests that nisin may be used in broiler nutrition as a growth promotor, with no negative influence on the bird's metabolism or immune status.

Molluscicidal activities of curcumin-nisin polylactic acid nanoparticle on Biomphalaria pfeifferi.

BACKGROUND: Snail intermediate host control is a widely canvassed strategy for schistosomiasis control in endemic countries. While there have been increasing studies on the search for potent molluscicides in the past years, the use of nanoparticulate agents as molluscicides is yet to gain wide attention. The aim of this study was to assess the molluscicidal potential of curcumin-nisin poly lactic acid (PLA) entrapped nanoparticle (CurNisNp) against Biomphalaria pfeifferi, a snail intermediate host for Schistosoma mansoni. METHODOLOGY/PRINCIPAL FINDINGS: CurNisNp formulated by double emulsion method was tested against the young adults, < 1 week, 1-2-week old juveniles, 1 day (blastula) and 7 day-old (hippo-stage) egg masses of B. pfeifferi. Mortality in the different stages was determined after 96-h of exposure at varying concentrations (350, 175, 87.5, 43.75 and 21.88 ppm). The sub-lethal effects of CurNisNp on the hatchability of the 7-day-old egg masses and egg laying capacity of the young adult snails were determined. The CurNisNp diameter, polydispersity index (PDI), zeta potential and drug entrapment efficiency were 284.0 ± 17.9 nm, 0.166 ± 0.03, -16.6 ± 2.45 mV and 35.0% respectively. The < 1 week old juveniles and the 1-day-old egg stage (blastula) of B. pfeifferi with LC50 277.9 ppm and 4279.5 ppm were the most susceptible and resistant stages to the drug respectively. CurNisNp was also observed to cause significant reductions (P<0.05) in egg hatchability and egg laying capacity with strong negative correlation between egg laying capacity and concentration (r = -0.928; P<0.05). CONCLUSION/SIGNIFICANCE: This study showed that CurNisNp has molluscicidal activities on different developmental stages of B. pfeifferi. It is therefore recommended that the formulation be more optimised to give a nanoparticle with a narrow range monodispersed PDI for better drug distribution and eventual greater molluscicidal activities.

Adverse effect of nisin resistance protein on nisin-induced expression system in Lactococcus lactis.

Nisin is a bacteriocin that is widely used as a safe, natural preservative in food products. Nisin-controlled gene expression (NICE) systems and food-grade expression systems with nisin resistance as the selection marker are increasingly attracting attention owing to their food-grade statuses. However, the putative influence of nisin resistance on NICE systems deserves consideration when nisin is used as both the inducer and selection agent in lactococcal strains. In this paper, we described the cloning of the nisin resistance gene (nsr) and studied the effect of the encoded nisin resistance protein (NSR) on the efficiency of the NICE system in Lactococcus lactis, with the green fluorescence protein as the reporter protein. Results showed that NSR expression significantly weakened the inducing activity of nisin. Further studies have confirmed that this reduction in the inducing activity of nisin was a consequence of the proteolytic activity of NSR against nisin; the digested products showed drastically decreased inducing activities than native nisin. Conclusively, the expression of NSR imposes an adverse effect on the NICE system in L. lactis.

Therapeutic effect of nisin Z on subclinical mastitis in lactating cows.

Bovine subclinical mastitis is an inflammation of the mammary gland caused by bacterial intramammary infection, accounting for large economic losses. Treatment of subclinical mastitis is not suggested for lactating cows due to the risk of milk contamination. The objectives of this study were to evaluate an antimicrobial peptide, nisin, in the treatment of subclinical mastitis in lactating cows. A total of 90 lactating Holstein cows with subclinical mastitis were randomly divided into nisin-treated (n = 46) and control (n = 44) groups. In the nisin-treated group, cows received an intramammary infusion of nisin at a dose of 2,500,000 IU once daily for 3 days while the control cows received no treatment. Milk samples were collected from the affected mammary quarters before treatment and 1 and 2 weeks after treatment for analyses of bacteria, somatic cells, and N-acetyl-beta-D-glucosaminidase (NAGase). Results indicated that nisin therapy had bacteriological cure rates of 90.1% for Streptococcus agalactiae (10 of 11), 50% for Staphylococcus aureus (7 of 14), 58.8% for coagulase-negative staphylococci (7 of 17), and 65.2% for all cases (30 of 46). Meanwhile, only 15.9% (7 of 44) of untreated cows spontaneously recovered. NAGase activity in milk samples and the number of mammary quarters with a milk somatic cell count of > or =500,000/ml were significantly decreased after nisin treatment while no significant changes took place in the control group. Because of its therapeutic effects on bovine subclinical mastitis, as well as its safety in humans, nisin deserves further study to clarify its effects on mastitis caused by different pathogens.

Multiplicação e sobrevivência de Listeria Monocytogenes sob condições ecológicas desfavoráveis. Parte II: Atmosfera modificada, agentes biológicos e compostos de limpeza e desinfecção / Multiplication and survival of Listeria Monocytogenes under unfavorable ecological conditions. Breaks II: Atmosphere modified, composed and biological agents of cleaning and disinfection

A larga distribuição de Listeria monocytogenes no meio ambiente está provavelmente relacionada com a sua capacidade para sobreviver e se multiplicar sob condições extremas. As novas tendências em termos de conservação de alimentos, incluem a utilização de bioconservantes, embalagens a vácuo e as atmosferas modificadas. O efeito antagónico da nisina em relação a Listeria monocytogenes já está demonstrado, contudo verifica-se que nos alimentos é bastante dependente da composição química do alimento ao qual é adicionada. Também os efeitos da embalagem de alimentos a vácuo e em atmosfera modificada na multiplicação de Listeria monocytogenes são controversos. A utilização de concentrações subletais de agentes de limpeza e desinfecção podem contribuir para o aumento da resistência de Listeria monocytogenes a esse compostos.

Multiplicação e sobrevivência de Listeria Monocytogenes sob condições ecológicas desfavoráveis. Parte II: Atmosfera modificada, agentes biológicos e compostos de limpeza e desinfecção / Multiplication and survival of Listeria Monocytogenes under unfavorable ecological conditions. Breaks II: Atmosphere modified, composed and biological agents of cleaning and disinfection

A larga distribuição de Listeria monocytogenes no meio ambiente está provavelmente relacionada com a sua capacidade para sobreviver e se multiplicar sob condições extremas. As novas tendências em termos de conservação de alimentos, incluem a utilização de bioconservantes, embalagens a vácuo e as atmosferas modificadas. O efeito antagónico da nisina em relação a Listeria monocytogenes já está demonstrado, contudo verifica-se que nos alimentos é bastante dependente da composição química do alimento ao qual é adicionada. Também os efeitos da embalagem de alimentos a vácuo e em atmosfera modificada na multiplicação de Listeria monocytogenes são controversos. A utilização de concentrações subletais de agentes de limpeza e desinfecção podem contribuir para o aumento da resistência de Listeria monocytogenes a esse compostos.

The wide distribution of Listeria monocytogenes in the environment is probably related to its ability to survive and grow in extreme conditions. New trends in food preservation include the use of biopreservatives, vacuum packaging and modified atmospheres. The antagonistic effect of nisin on L. monocytogenes has been demonstrated but its activity in foods is strongly dependent on the chemical composition of the food to which is added. Also the effects of vacuum packaging and modified atmosphere packaging on the growth of L. monocytogenes are still controvertial. Sublethal concentrations of cleanning and desinfectants agents can contribute to the and increased resistance of L. monocytogenes to these compounds.