Tânia Lúcia Montenegro Stamford

Antimicrobial effectiveness of spices: an approach for use in food conservation systems

There has been constant an increasing the search alternative and efficient compounds for food conservation, aiming a partial or total replacement of antimicrobial chemical additives. Spices offer a promising alternative for food safety. Inhibitory activity of spices and derivatives on the growth of bacteria, yeasts, fungi and microbial toxins synthesis has been well reported, so they could be used in food conservation as main or as adjuvant antimicrobial compounds in order to assure the production of microbiologically stable foods.

Microbial biosurfactants as additives for food industries

Microbial biosurfactants with high ability to reduce surface and interfacial surface tension and conferring important properties such as emulsification, detergency, solubilization, lubrication and phase dispersion have a wide range of potential applications in many industries. Significant interest in these compounds has been demonstrated by environmental, bioremediation, oil, petroleum, food, beverage, cosmetic and pharmaceutical industries attracted by their low toxicity, biodegradability and sustainable production technologies. Despite having significant potentials associated with emulsion formation, stabilization, antiadhesive and antimicrobial activities, significantly less output and applications have been reported in food industry. This has been exacerbated by uneconomical or uncompetitive costing issues for their production when compared to plant or chemical counterparts. In this review, biosurfactants properties, present uses and potential future applications as food additives acting as thickening, emulsifying, dispersing or stabilising agents in addition to the use of sustainable economic processes utilising agro‐industrial wastes as alternative substrates for their production are discussed.

Inhibition of Staphylococcus aureus in broth and meat broth using synergies of phenolics and organic acids.

This study assessed the occurrence of an enhancing inhibitory effect of the combined application of thymol and carvacrol with lactic and acetic acid against Staphylococcus aureus using the determination of Fractional Inhibitory Concentration (FIC) index and kill-time assay in meat broth and in a food model (meat). Minimum Inhibitory Concentration (MIC) of carvacrol and thymol were 1.25 and 0.6 microL/mL, respectively. FIC indices of the combined application of the phenolic constituents and organic acids were 0.5 suggesting a synergic interaction. No difference (p>0.05) was found among the bacterial counts for the meat broth added of the phenolics alone or in combination with lactic acid at sub-inhibitory concentrations. Contrarily, the bacterial counts found for the meat broth added of the phenolics alone were significantly lower (p<0.05) than the counts obtained for the broth added of the combination of phenolics and acetic acid. No difference (p>0.05) was found among the bacterial counts for the meat model added of phytochemicals alone and in combination with the organic acids. The tested antimicrobials alone or in mixture provided smaller anti-staphylococcal effect in meat broth than in meat model. These results could arise as an interesting approach for the improvement of food preservation using more natural procedures, considering the current demand of consumer and sensory quality of foods.

Sensitivity of spoiling and pathogen food-related bacteria to Origanum vulgare L. (Lamiaceae) essential oil

Origanum vulgare L. (oregano), Lamiaceae, has been known as plant specie with prominent biological properties for a long time. This study aimed to evaluate the antibacterial activity of Origanum vulgare essential oil on various Gram-positive and Gram-negative spoiling and/or pathogen food-related bacteria, as well as to observe its antimicrobial effectiveness in a food conservation micromodel. The results showed a strong antibacterial activity of the assayed essential oil noted by large growth inhibition zones (30-37 mm). MIC values were between 20-40 µL/mL for the most bacteria strains. Essential oil was able to cause significant (P<0.05) inhibitory effect on the bacteria viability providing a bacteriostatic effect after 24hours of exposure. In addition, the MIC provided a significant (P<0.05) decrease of the autochthonous bacterial flora in ground meat samples stored under refrigeration. These results support the possibility of using Origanum vulgare essential oil as alternative antimicrobial compound in food conservation systems.

Staphylococcus enterotoxigênicos em alimentos in natura e processados no estado de Pernambuco, Brasil

Food contamination has increased in the recent years and actually represents a serious risk for human health. The occurrence of Staphylococcus spp. in nature and processed foods were identified by Gram test, catalase, coagulase, DNAase, acetoin production (AP) and by assays of carbohydrate metabolism (glucose, maltose and mannitol). Strains of Staphylococcus spp were selected by thermonuclease reaction and analysis of staphylococcal enterotoxins, detected by immunoenzymatic assays (VIDAS - Staph Enterotoxin - bio Merieux). Positive reaction for staphylococci enterotoxin was produced by S. aureus in shrimps; farmhouse cheese and macaroni mass; S intermedius in cooked fish and garlic paste. SCP (Staphylococci Coagulase Positive) were observed in farmhouse cheese. Contamination by Staphylococcus sppoccurred during food production and storage. We can conclude that practices of hygiene need to be observed during food production and storage.

Growth of Cunninghamella elegans UCP 542 and production of chitin and chitosan using yam bean medium

Microbiological processes were used for chitin and chitosan productions by Cunninghamella elegans (UCP 542) grown in a new economic culture medium. The assay was carried out to evaluate the growth of C. elegans using yam bean ( Pachyrhizus erosus L. Urban) medium, in different times of growth (24, 48, 72 and 96 hrs), incubated at 28oC in an orbital shaker at 150 rpm. The lyophilized biomass was determined by gravimetry. The polysaccharides were extracted by alkali-acid treatment, and characterized by infrared spectroscopy, titration and viscosity. C. elegans grown in the yam bean medium and produced higher yields of biomass (24.3 g/ mL) in 96 hrs. The high level was chitosan (66 mg/g), and chitin (440 mg/g) were produced at 48 and 72 hrs of growth, respectively. The polysaccharides showed degree of deacetilation and viscosimetric molecular weight as: 6.2% and 3.25 x10 4 g/mol for chitin, and 85% and 2.72 x 10 4 g/mol for chitosan, respectively. The results obtained suggest high biotechnological potential of yam bean as an economic source to produce chitin and chitosan by C. elegans . In addition, the new medium using yam bean for production of the chitin and chitosan may be used for many purposes to reduce the cost price of fermentation processes.

Enterotoxigenicidade de Staphylococcus spp. isolados de leite in natura

Foods are susceptible to contamination for different etiological agents, which can take to manifested diseases by action of pathogenic microorganisms or their toxins. It was researched the occurrence of strains of Staphylococcus and your capacity in producing enterotoxins in milk in natura, that have been produced or commercialized in the State Pernambuco, Brazil. 109 strains of Staphylococus positive and negative coagulase of milk in natura were selected. The identification of the isolated strains was accomplished through morphologic and biochemical tests as: catalase, coagulase, haemolysins, DNAse, thermonuclease, acetoin production (VP) and carbohydrates metabolism (glucose, maltose and mannitol). From the 77 coagulase positive strains 30 were identified as S. aureus, 3 as S. hyicus, 16 as S. intermedius, 13 as S. aureus identification presumptive and 15 as SCP. Among 32 coagulase negative strains 2 were identified as S. capitis, 1 as S. carnosus, 6 as S. chromogenes, 1 as S. hyicus, 1 as S. schleiferi and 21 as SCN. Fourty-three strains that presented very evident thermonuclease reaction, were selected in order to perform for staphylococcal enterotoxins analysis by the immuno enzimatic test (ELFA). 10 strains showed negative reaction for enterotoxins: S. aureus (4), S. carnosus (1), S. chromogenes (2), S. hyicus (2) and S. intermedius (1). Strains that gave positive results, were S. aureus (17), S. chromogenes (2), S. hyicus (1), S. intermedius (8), S. aureus identified presumptively (2) and of the groups SCP (1) and SCN (2). The species that presented larger number of enterotoxigenics strains were S. aureus and S. intermedius. Results can be attributed to the inadequate manipulation or food recontamination during the storage and distribution.

ATIVIDADE ENZIMÁTICA DE MICRORGANISMOS ISOLADOS DO JACATUPÉ (Pachyrhizus erosus L. Urban)

The isolation and identification of microorganisms that produce enzyme of commercial interest utilizing tubers of yam bean legume (Pachyrrizus erosus L. Urban) was the main objective of this work. Endophytic and epiphytic microorganisms were isolated by micromorphologyc observation. The agar diffusion method was used to determine the enzymatic activity. Sixty-eight isolates from yam bean tubers were cultured at 280 C in solid medium specific to amylase, lipase, protease and cellulase for 96h. The epiphytic microorganisms Pithomyces (7,3%), Aspergillus (19,2%), Fusarium (5,9%) and Trichoderma (5,8%) and the endophytic microorganisms Mucor (7,3%), Rhizopus (10,3%) Bacillus (19%), Staphylococcus (10,3%) and Nocardiopsis (15%) were isolated. Compared to the specific standard culture Nocardiopsis sp. showed higher lipolytic activity and similar amylolitic activity. Mucor sp., Pithomyces sp. and Staphylococcus sp, produced proteolytic activity lower than the standard culture. None isolate showed celulolytic activity.

Physico-chemical characteristics and functional properties of chitin and chitosan produced by Mucor circinelloides using yam bean as substrate.

Microbiological processes were used for chitin and chitosan production by Mucor circinelloides (UCP 050) grown in yam bean (Pachyrhizus erosus L. Urban) medium. The polysaccharides were extracted by alkali–acid treatment and structural investigations by X-ray diffraction, Fourier transform IR analysis, viscosity and thermal analysis by TG, DTG, and DTA were done. The highest biomass yield (20.7 g/L) was obtained at 96 hours. The highest levels of chitosan (64 mg/g) and chitin (500 mg/g) were produced at 48 and 72 hours, respectively. It was demonstrated that yam bean shows great potential as an economic medium and it is possible to achieve a good yield of chitosan with chemical properties that enable its use in biotechnological applications.

Ocorrência de Cryptosporidium spp. e outros parasitas em hortaliças consumidas in natura, no Recife

O objetivo deste estudo foi verificar a ocorrencia de enteroparasitas em hortalicas comercializadas e consumidas em Pernambuco. Foram utilizadas 100 amostras de hortalicas: 40 amostras de alface lisa (Lactuca sativa), 40 de agriao (Nasturtium officinale) e 20 de acelga (Beta vulgaris), provenientes de feiras livres e supermercados. A deteccao de Cryptosporidium spp. foi realizada conforme Monge e Arias sendo utilizado dois metodos de coloracao, Koster modificado e Ziehl-Nielsen. Foi usada a tecnica de sedimentacao espontânea de Gelli et al. para a analise parasitologica. As analises de coliformes totais e Escherichia coli foram realizadas de acordo com Andrews. Os resultados obtidos mostraram um percentual de contaminacao parasitaria em 60% de alface, 30% de agriao e 20% de acelga, destacando-se o Ascaris lumbricoides, Strongyloides stercoralis e Ancylostoma duodenale dentre os helmintos, e o Cryptosporidium spp., Entamoeba coli e o complexo Entamoeba histolytica/Entamoeba dispar, dentre os protozoarios com maior frequencia. As hortalicas mais contaminadas por coliformes totais e Escherichia coli foram alface nas amostras de supermercado e agriao em feira livre. Esses dados sugerem a necessidade da adocao de medidas educativas aos produtores, e do monitoramento das aguas destinadas a irrigacao das hortas.