Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Biocontrol applications such as using phages against the contamination of Listeria monocytogenes are promising trends in terms of reducing the use of chemical additives in food industry. The aim of this study was to determine the effectiveness of Listex P100 phage (phage P100) on different Listeria monocytogenes strains (PL2, PL3, PL9 and PL10) in pasteurized milk and broth. Survival data of L. monocytogenes were successfully described by Weibull model. Time parameter of the Weibull model was used to evaluate the phage-resistances of L. monocytogenes strains. The reduction of L. monocytogenes was greater in broth than in milk regardless of the temperature level and it was significantly higher at 30 °C than at 4 °C in both media. The reductions of L. monocytogenes strains by the phage treatment were between 2.7 to 3.4 log10 units at 30 °C and 1.4 to 2.1 log10 units at 4 °C after 4 days of incubation in broth whereas 1.9 to 2.9 log10 units and 1.0 to1.6 log10 units were observed after 4 days of incubation in milk at 30 °C and 4 °C, respectively. It was found that L. monocytogenes PL2 is the most phage-resistant strain in broth at 30 °C and at 4 °C, and in milk at 30 °C, while L. monocytogenes PL9 is the most phage-resistant L. monocytogenes strain in milk at 4 °C. This study demonstrated P100 phage could be used to control L. monocytogenes counts in milk.

Viruses have been present throughout human history, causing diseases due to infections and food poisoning; they have caused frequent public health problems worldwide. These illnesses are usually mild, moderate, or severe in nature. The personal hygiene of food handlers and processing processes should be checked periodically. Virus detection protocols and safety measures should be continually reviewed as viruses change their mode of infection. The objective of this review was to discuss the possible routes of virus transmission to humans through food. Important topics have been reviewed such as: definition of food viruses, presence, and types of viruses in food, enteric viruses, zoonotic viruses, water as a means of transmission, risks of infection, other non-conventional foods as potential transmitters of viruses and food safety, in addition to current and future challenges, research work on viruses more resistant to heat treatments in food should be sought. Also, future work on survival time of active viruses on food surfaces. In addition, studies that determine the mechanisms of virus mutation in relation to the conditions of food handling and processing.

Orchids have a long period of production and need to be under the right conditions. Therefore, in vitro propagation is an alternative to reduce production time. This study aimed to determine the optimal in vitro propagation conditions in two species of orchids, Cattleya maxima Lindl. and Phalaenopsis amabilis (L.) Blume. For this goal, two experiments were carried out: multiplication and rooting, for both species. In the multiplication experiment, the treatments were differentiated according to the complement of MS (Murashige and Skoog medium), banana flour, kinetin or 6-Benzylaminopurine (BAP). Meanwhile, in the rooting experiment, the complements were banana flour, Indol-3-butiric acid (IBA), Naphthaleneacetic acid (NAA) or 2,4-Dichlorophenoxyacetic acid (2,4-D). According to the results, banana flour (50 g.L-1) increased the plantlet height in C. maxima (multiplication) and P. amabilis (rooting). Kinetin (0.003 g.L-1) and BAP (0.005 g.L-1) increased the number of shoots and leaves in C. maxima, in multiplication experiment. In rooting experiment, NAA (0.003 g.L-1) increased significantly the number of leaves in C. maxima. The root formation was notably stimulated by banana flour in both species. Likewise, 2,4-D (0.003 g.L-1) can cause phytotoxic effects and inhibit root formation. In conclusion, C. maxima was more robust than P. amabilis since in all studied variables the former presented the highest values. Furthermore, C. maxima responds adequately to application of kinetin and BAP to increase the aerial part of the plant, however, they inhibit the root formation. In contrast, kinetin and BAP do not limit root growth in P. amabilis.

The circular economy, as a factor of sustainable development, is an innovative practice of resource allocation that considers the production of goods and the reuse of their waste. Society values the circular economy, since it contributes to the reduction of negative externalities arising from the operation of certain industries that generate waste that is harmful to the environment. In this work, the magnitude of the negative externality represented by the accumulation of the waste called "alperujo" in the olive sector in Chile is evaluated, identifying, and validating new businesses developed from its reuse. For this purpose, a portfolio of viable options for the valorization of alperujo was constituted, based on a contextual analysis, the application of Product-Market Fit and the participation of a focus group, which allowed estimating the reduction of the negative externality, because of the use of alperujo. This industry externality comes from the generation of 120,000 t/year of waste, with an estimated value of USD 10.48 million. The alperujo, in the form of paste or extract, can be incorporated in the production of snacks, antioxidant drinks and yogurt. The sum of the NPV of the three businesses reaches USD 11.63 million, which allows compensating the estimated negative externality with a favorable margin, using 1.8% of the alperujo generated annually in Chile. This study contributes to the validation of the circular business model in a relevant sector of the Chilean export economy.

The physicochemical and biological indices have been used in isolation; if the parameters of these indices were applied in an integrated manner, they would bring together in a single measure the functional and structural variability of the biotic and abiotic components of water quality. The aim of this study was to build a comprehensive water quality index. Eleven sampling points were selected considering different degrees of agro-industrial intervention. 21 abiotic variables and 27 biological metrics were measured. Macroinvertebrates were quantitatively collected and identified to family taxonomic level. Using Principal Component Analysis, after standardization and exclusion of uncorrelated variables (VIF ≤ 10), the abiotic gradient was determined, which represented the abiotic variables that explained the disturbances in the water; with the abiotic gradient and the biological metrics, a Pearson correlation was performed, and those biological metrics that presented a high and non-redundant correlation were selected (Pearson 0.6 ≤ r ≤ 0.8); with the selected biological metrics, we proceeded to formulate and categorize the index; finally, by means of simple linear regression, the proposed index was compared with five other indexes (ICA, ICOMO, EPT, BMWP/col. and ASPT). The results showed that the abiotic gradient was defined by CP 1 which explained 65.5% of the accumulated variance, represented by altitude (r = 0.411), iron (r = 0.345) and dissolved oxygen (r = 0.329). The biological metrics used for the index design were: % scrapers, % swimmers, NEF of order 2, Ephemeroptera and Trichoptera tolerance. It was concluded that the integral index presents a higher predictive level (R2 = 0.87) of water quality, compared to the other indices: ASPT (R2 = 0.79), BMWP/col. (R2 = 0.68), EPT (R2 = 0.61), ICOMO (R2 = 0.35) and ICA (R2 = 0.27).

The complications caused by the generation of resistance in the psyllid Bactericera cockerelli by chemical pesticides, raise the need for the alternative use of products that reduce resistance and ensure better control. The species Crotalaria longirostrata is a source of secondary metabolites, which show possible activity against insect pests. The objective of the research was to identify the compounds of the crude methanolic extract of C. longirostrata leaves, as well as to evaluate their biological activity on B. cockerelli nymphs. Twenty-five compounds were identified by Gas Chromatography coupled to Mass Spectrometry (GC-MS) analysis; the most abundant was 1β,2β-epoxy-1α-methoxymethyl-8α-pyrrolizidine; an alkaloid of the iminosugar group, reported for the first time in C. longirostrata, of which concentrations from 2 to 30 mg/mL of the methanolic extract had to be prepared to evaluate on B. cockerelli nymphs. It showed that at 48 h, there was a mortality of 73.2%-100% in the treatments of 8, 12, 16, 20, and 30 mg/mL. The mean lethal concentration (LC50) was 4.78 mg/mL and LC95 14,52 mg/mL. The results obtained with the methanolic extract of C. longirostrata leaves for controlling the insect B. cockerelli suggest that it can potentially be used as an alternative insecticide of botanical origin to manage the insect.

Classifying small agricultural producers based on their technical efficiency and economic performance allows us to gauge the potential to improve yield in the quinoa crop, promote local food security, and improve rural incomes. Consequently, the objective of this study was to characterize and classify quinoa producers at the Peruvian Altiplano based on their productive, economic, and social attributes, so the technical efficiency and economic performance of the identified groups can be analyzed. Hence, 409 surveys conducted among quinoa producers in the Puno region were used to run the statistical analysis using two-stage cluster techniques, stochastic frontier, linear regression, and ANOVA tests. The results revealed that three groups of producers exhibited discriminating variables in the use of fertilizers, organic fertilizers, weed control, application of fungicides, production of quinoa, the total area of all crops, and achievement of economic benefits. It was evidenced that the use of seeds and fertilizers, in optimal quantities, increased yield, and in combination with quinoa sales, were the significant variables to differentiate technical efficiency. The high Andes are characterized by smallholdings, subsistence agriculture and, agrobiodiversity conservation and, although cultivation practices are predominantly low technical efficient, it would be possible to rapidly increase agricultural performance with a better allocation of external inputs. However, this could be done to regional limits, for this reason, the role of public policy is very important so that producers can get broader access to production inputs and technical services.

Climate change, as well as the appearance of pests and diseases, are affecting olive plantations (Olea europaea L.) and the production of olives in the world, therefore, there is an urgent need for tools to help us identify the spatial and temporal evolution of the olive groves, regarding the attack of pests, in this case, the Orthezia olivicola and the olive borer Phloeotribus scarabaeoides. In this work, we use information from freely available satellite images that allowed us to carry out spatial and temporal analysis and the combination of vegetation indices. For the studied area, according to the values of the NDVI (Normalized Difference Vegetation Index), it was identified that the surface of diseased plants ranges from 42% to 68%, moderately healthy plants from 2% to 18%, and the state of the plantation considered as very healthy plants with a tendency to zero, which means that practically 100% of the olive trees are affected by some level. The temporal variation of the NDVI, DVI, SAVI, GNDVI, EVI2, and MSAVI indices, allowed us to establish the states of affectation as mild, moderate pest attack, the severity of the pest attack added to the water deficit, and very strong pest attack and state of permanent wilting.

Negative impacts of climate change are expected in the production of Coffea arabica L. one of the most commercialized tropical agroproducts in the world. However, most studies work with global circulation models, being of little use in making decisions on the scale of farm management. Given this, the objective of this study was to identify the suitability for the cultivation of C. arabica in the face of climate change and how tree cover mitigates the impacts of climate change in an agroforestry plot. The indices of climatic extremes were calculated (1961 to 2016 for Coatepec; 1985 to 2016 for Briones) and a trend analysis was carried out (Mann-Kendall). The temperature inside a plot, and on an open site, was monitored for two years (2017-2019). This was related to the climatic requirements of C. Arabica. Trends of increase (p < 0.05) of the minimum and minimum extreme annual temperatures were identified in the two stations near the plot (0.24 and 0.69 °C·decade-1 in Coatepec and 0.46 and 0.79 °C·decade-1 in Briones). The maximum temperature did not present significant increases, reducing the thermal amplitude. Both annual and seasonal precipitation shows trends of increase in intensity. All these conditions are still suitable for the cultivation of C. arabica. At the plot scale, the importance of tree cover is demonstrated, which in this agroforestry system allows to reduce the maximum temperature by 1.9 °C compared to an open site. Tree cover has also made it possible to mitigate extreme events.

Nematophagous fungi can feed on nematodes under nutrient-poor conditions. They live in the soil and their study is important because of their possible use in the biocontrol of phytoparasitic nematodes. These fungi can be cultivated in the laboratory using different media and substrates, making them potential agents for agricultural use in tropical environments. The objective was to review recent scientific advances in the ecological interactions of nematophagous fungi and their prey, with emphasis on their use as biological controllers. Given the importance of their interactions in the soil, diversity, abundance, dispersal, and colonization of different types of habitats, these fungal microorganisms can be specialists or generalists in the predation of nematode populations in their various stages (egg, juvenile or adult). The different scientific advances and applications of predatory fungi in some tropical crops in Latin American countries are also briefly described. After these explorations, it is possible to conclude that the integrated application of microorganisms in the soil could improve the production of some cultivars by efficiently reducing nematode populations. In addition, it could improve the structure of soil trophic interactions, with environmentally benign treatments that reduce the use of chemical pesticides.