Nitrite-free implications on consumer acceptance and the behavior of pathogens in cured pork loins

Research Areas Food Science & TechnologyCured pork loins are valued products due to their particular sensory characteristics. These products are usually prepared with nitrite to guarantee adequate color and pathogen control. The use of nitrite in meat products has been criticized due to its potential contribution to carcinogenic N-nitroso-compound formation. The present work aimed to evaluate the effect of eliminating nitrite from the manufacturing of cured loins made with wine- and water-based marinades on the color evaluation of consumers and on the behavior of Clostridium sporogenes, Listeria monocytogenes, and Salmonella. The use of nitrite in processing cured loins resulted in a color considered adequate by more than 50% of the consumers. When nitrite was not used, the color was described mainly as weak. The hedonic evaluation of cured loins did not reflect the color evaluation. The samples with a weak and an adequate color had similar hedonic evaluations. The present work did not allow us to infer the potential interest in injecting S. xylosus into meat to prepare cured loins. The use of nitrite did not affect the survival of Cl. sporogenes, L. monocytogenes, or Salmonella. The reduction in the aw was the primary determinant influencing pathogen survival. The production of nitrite-free cured loins seems possible once the control of pathogens can be achieved. However, the product will have a weaker color. Consumers appreciate sensory aspects other than color, which, combined with the positive impact of the “additive-free” claim, can support the possibility of producing cured loins without nitriteinfo:eu-repo/semantics/publishedVersio

Editorial: natural compounds in food safety and preservation

Research Areas: Nutrition & Dieteticsinfo:eu-repo/semantics/publishedVersio

Staphylococcus saprophyticus causing infections in humans is associated with high resistance to heavy metals

Research Areas: Microbiology ; Pharmacology & PharmacyStaphylococcus saprophyticus is a common pathogen of the urinary tract, a heavy metal-rich environment, but information regarding its heavy metal resistance is unknown. We investigated 422 S. saprophyticus isolates from human infection and colonization/contamination, animals, and environmental sources for resistance to copper, zinc, arsenic, and cadmium using the agar dilution method. To identify the genes associated with metal resistance and assess possible links to pathogenicity, we accessed the wholegenome sequence of all isolates and used in silico and pangenome-wide association approaches. The MIC values for copper and zinc were uniformly high (1,600mg/liter). Genes encoding copper efflux pumps (copA, copB, copZ, mco, and csoR) and zinc transporters (zinT, czrAB, znuBC, and zur) were abundant in the population (20 to 100%). Arsenic and cadmium showed various susceptibility levels. Genes encoding the ars operon (arsRDABC), an ABC transporter and a two-component permease, were linked to resistance to arsenic (MICs$1,600mg/liter; 14or cadC and cadD-cadX or czrC) and genes encoding multidrug efflux pumps and hyperosmoregulation in acidified conditions were associated with resistance to cadmium (MICs$ 200mg/liter; 20% [85/422]; P, 0.05). These resistance genes were frequently carried by mobile genetic elements. Resistance to arsenic and cadmium were linked to human infection and a clonal lineage originating in animals (P, 0.05). Altogether, S. saprophyticus was highly resistant to heavy metals and accumulated multiple metal resistance determinants. The highest arsenic and cadmium resistance levels were associated with infection, suggesting resistance to these metals is relevant for S. saprophyticus pathogenicityinfo:eu-repo/semantics/publishedVersio

Addition of vinegar to extend the shelf-life of "Cabeça de Xara"

Cabeça de xara es un producto de carne listos para comer, cuya producción es muy característica en el Alentejo, una región de Portugal. Es una galantina que generalmente se moldea en forma de paralelepípedo. Se elabora con varias carnes obtenidas de la raza porcina Alentejana y criada en la misma región, cabezas de cerdo deshuesadas, lengua y tejido conectivo, a la que se le añade una serie de condimentos como sal, perejil, vino y pimienta. Este trabajo se pretende poner a prueba la viabilidad de añadir vinagre con el fin de aumentar la vida útil de la cabeça de xara, mediante la reducción de la microbiota contaminante responsables del deterioro, así como el control del patógeno Listeria monocytogenes. Tres lotes independientes fueron producidos y con composición proximal parecida, se evaluó pH, aw, parámetros microbiológicos y contenido de aminas biogénicas. El análisis sensorial se realizó también durante todo el período de almacenamiento. No se encontraron diferencias significativas entre las muestras control y vinagre en cuanto a la composición proximal de cabeça de xara. Como era de esperar, el pH fue menor en las muestras con vinagre, sin embargo se observaron diferencias en aw entre los dos tratamientos. L. monocytogenes estuvo presente desde el primer mes sólo en un lote, en el tratamiento control. Sin embargo, es inhibida por la adición de vinagre de vino hasta el tercer mes de almacenamiento, donde L. monocytogenes está presente pero por debajo del límite establecido en el Reglamento 2073/2005. La presencia de vinagre redujo significativamente el contenido de aminas biógenicas, en particular cadaverina, putrescina y tiramina, durante todo el período de almacenamiento. En cuanto a la evaluación sensorial, el sabor a vinagre fue evaluado por los panelistas de manera negativa

The risk of salt reduction in dry-cured sausage assessed by the influence on water activity and the survival of salmonella

Research Areas: Food Science & TechnologyWater activity (aw) is the main hurdle for microbial control in dry-cured sausages. The aw can be influenced by drying or adding electrolytes or humectants. Dry-cured meat products are partially dried, which, together with added salt, results in safe aw values. Currently, there is a trend to reduce salt in meat products, which can compromise the preservation process. The present work aims to evaluate the influences of added salt levels (1% or 3%) and the use or omission of phosphates and wine on the aw of a dry-cured sausage, and to evaluate the possibility of estimating the aw from the moisture loss and the behavior of Salmonella during dry-cured sausage (chouriço) processing. There was a strong relationship between moisture and aw, regardless of the salt level and the presence of phosphates or wine. Predicting aw from moisture loss is possible using the Boltzmann sigmoid function. The salt level strongly influences Salmonella behavior, mainly through aw reduction. An increase in aw by 0.01 units reduced the odds of achieving a 5-log reduction in Salmonella counts to half. Increasing added salt from 1% to 3% increased the odds of achieving a 5-log Salmonella reduction 7.5-fold. The current trend to reduce salt in foods must be carefully approached if applied to cured meat products, as it has substantial consequences on aw evolution and Salmonella survivalinfo:eu-repo/semantics/publishedVersio

Assessment of biofilm formation by Campylobacter spp. isolates mimicking poultry slaughterhouse conditions

Research Areas: AgricultureThis research aimed to assess the biofilm formation ability of Campylobacter strains under temperature and oxygen stress conditions, similar to those found in the industrial environment, to explain the persistence of this pathogen on the poultry slaughter line. A collection of C. jejuni and C. coli isolates (n = 143) obtained from poultry samples (cecal content and neck skin), collected at slaughterhouse level, from diverse flocks, on different working days, was genotyped by flaA-restriction fragment length polymorphism (RFLP) typing method. A clustering analysis resulted in the assignment of 10 main clusters, from which 15 strains with different flaA-RFLP genotypes were selected for the assessment of biofilm formation ability and antimicrobial susceptibility. Biofilm assays, performed by crystal violet staining method, were conducted with the goal of mimicking some conditions present at the slaughterhouse environment, based on temperature, atmosphere, and contamination levels. Results indicated that many C. jejuni strains with similar flaA-RFLP profiles were present at the slaughterhouse on different processing days. All the strains tested (n = 15) were multidrugresistant except for one. Biofilm formation ability was strain-dependent, and it appeared to have been affected by inoculum concentration, temperature, and tolerance to oxygen levels. At 10 degrees C, adherence levels were significantly lower than at 42 degrees C. Under microaerobic and aerobic atmospheres, at 42 degrees C, 3 strains (C. jejuni 46E, C. jejuni 61C, and C. coli 65B) stood out, exhibiting significant levels of biofilm formation. C. jejuni strains 46E and 61C were inserted in clusters with evidence of persistence at the slaughterhouse for a long period of time. This study demonstrated that Campylobacter strains from broilers are capable of forming biofilms under conditions resembling the slaughterhouse environment. These results should be seen as a cue to improve the programs of hygiene implemented, particularly in those zones that can promote biofilm formation.info:eu-repo/semantics/publishedVersio

Impact of nitrite on the microbiological quality of a Portuguese Salpicão

info:eu-repo/semantics/publishedVersio

Shelf-life extension and quality improvement of a Portuguese traditional ready-to-eat meat product with vinegar

Cabec a de xara is a traditional ready-to-eat meat product (RTEMP) from the Portuguese region of Alentejo. It is a moulded galantine made of low value pork pieces. The aim of this work was to test the addition of vinegar in reducing the spoilage microbiota, as well as controlling Listeria monocytogenes, in order to increase the shelf-life of cabec a de xara. Physicochemical (fatty acids and biogenic amines profiles), microbiological (mesophiles, psychrotrophic bacteria, enterobacteria, yeasts and L. monocytogenes) and sensory analyses were performed throughout the storage period. RTEMP vinegar samples always showed lower microbiological counts than control samples. Moreover, RTEMP vinegar samples showed significantly lower contents in vasoactive amines throughout the storage period, which might be explained by their significantly lower enterobacteria counts. Concerning sensory analysis, RTEMP vinegar samples generally scored higher in overall appreciation. Our results showed that shelf-life of cabec a de xara may be extended from 1 to 3 months

Effect of autochthonous starter cultures in the production of "Paio", a traditional Portugese dry-cured sausage

En los países mediterráneos, como Portugal, los embutidos curados tradicionales son muy apreciados. A menudo se siguen fabricando en pequeñas unidades de procesamiento, de acuerdo con los procedimientos tradicionales. Los objetivos del presente estudio fueron evaluar el efecto de diferentes cultivos iniciadores y su concentración óptima, para reducir la carga microbiana y las aminas biogénicas en productos finales, con el objetivo de mejorar la seguridad de los embutidos sin deteriorar la aceptación sensorial. pH, aw, perfil microbiológico, aminas biogénicas, análisis del perfil de color y textura fueron evaluados. Las cepas y las concentraciones a utilizar, se seleccionaron en base a resultados previos: Staphylococcus xylosus, Lactobacillus sakei y una cepa de levadura a una concentración de 106 ufc / g de masa de carne cada una, se añadió 0,25% de dextrosa. Siempre se utilizó un lote control sin cultivos iniciadores. Los valores de aw fueron menores en los embutidos inoculados. En general, los valores de pH fueron ligeramente superiores en los embutidos inoculados. El tratamiento con L. sakei solo fue el más efectivo en la reducción del nivel de contaminación con L. monocytogenes, sin embargo este efecto parece perderse en cultivos mixtas. La inoculación, disminuyó generalmente el contenido de putrescina, de cadaverina y de tiramina. La inoculación de levadura parece contribuir al color más oscuro de los Paios. Con respecto a la textura, el Paio control demostró valores más altos de la dureza

Occurrence of Campylobacter spp. in carcasses of pigs slaughtered for consumption in Portugal.

The present study was designed to determine the prevalence of Campylobacter spp. in pig\u27s carcasses slaughtered for consumption in Portugal. The present study showed that 86 % of the carcasses swab samples collected at a pig slaughterhouse were contaminated with Campylobacter spp. From those, 45 colonies were isolated: 96.83% were identified as Campylobacter coli and 2,17% as Campylobacter jejuni. This result underlines the significance of pork carcasses contamination with Campylobacter spp., and emphasises the importance of implementing measures in order to reduce this food borne pathogen from the pork production chain. Further studies, using molecular tools, arc being developed by the authors in order to evaluate the level of faecal contamination