The food cold chain is an effective tool that allows food markets to maintain food quality and reduce losses. Poor logistics may result in foodborne disease outbreaks and greenhouse gas emissions caused by organic matter decay. The ongoing pandemic of COVID-19 makes it necessary to study the chances of SARS-CoV-2 transmissions in food products. This study reviews cold chain logistics as a handy tool for avoiding food safety risks, including COVID-19. The cold chain of perishables and its proper management make it possible to maintain quality and safety at any stage of the food supply chain. The technology covers each link of the food chain to prevent microbial spoilage caused by temperature fluctuations and the contamination with SARS-CoV-2 associated with perishable foods. Given the lack of knowledge in this field in Latin America, the region needs new research to determine the impact of the cold chain on perishable foodstuffs. The perishable cold chain is only as strong as its weakest link, and the national and international markets require new traceability protocols to minimize the effect of COVID-19.

<p><em>Leucaena leucocephala</em> (Lam.) de Wit (Leucaena) is a woody fodder legume with extensive use as livestock feed in the tropics becasuse of its adaptation and productivity in tropical environments. This review discusses benefits of Leucaena as feed for bovines in realtion to tropical grasses, among these benefits are: lower methane (CH₄) emission; higher intake of protein, Ω₃ fatty acids and minerals; incorporation of atmospheric nitrogen (N₂) to the soil-plant-animal chain; and, higher N efficiency by the bovine. Mimosine and concentration of condensed tannins above 5% might cause digestive disorders in bovines, then Leucaena intake has to be controlled and use of Leucaena populations with lower mimosine and condensed tannins concentrations. Silvopastoral systems are an option to have Leucaena available for grazing cattle, row tree planting has shown higher animal production than scattered trees and cluster. Silvopastoral system with Leucaena can increase total available forage by 8.7 t of DM ha^-1 yr^-1, this additional forage can have 22 to 25% and 55 to 61% crude protein and <em>in vitro</em> dry matter digestibility, respectively. Planned incorporation of Leucaena to the grazing areas has shown to yield 9.1 to 9.8 kg of milk cow^-1 day^-1 or 11957 to 14403 kg milk ha^-1 yr^-1; and, 693 to 851 g of live-weight gain animal^-1 day^-1 or 788 to 1337 kg of live-weight ha^-1 yr^-1. Leucaena inclusion on grazing areas improves livestock productivity in tropical areas with lower environmental impact than tropical grasses alone; however, more reaserch is needed to overcome some Leucaena agronomic and nutritional limitations.</p>

Se evaluó el impacto del pastoreo mixto vaca-oveja y de mono-especie (vaca) en dos tipos de pradera; alfalfa- ovillo (Medicago sativa-Dactylis glomerata) y otro con avena-ballico anual (Avena sativa-Lolium multiflorum), usando vacas Holstein y ovejas Criollas, sobre la calidad, desarrollo y rendimiento de forraje. El estudio, fue desarrollado bajo un diseño completamente al azar con dos repeticiones. El tipo de pastoreo no influyó (p>0.05) en cantidad, composición botánica y altura del forraje ofrecido. La dieta de vacas en pastoreo mixto sobre alfalfa- ovillo mostró cuatro veces más (p<0.05) material muerto que la de mono-especie. Las ovejas consumieron más (p<0.05) hojas de alfalfa y ballico anual que las vacas acompañantes. Solamente en alfalfa-ovillo las vacas en pastoreo mono-especie pastorearon 55% más tiempo (p<0.05) que las del mixto. El pastoreo mixto vacas-ovejas en praderas de dos especies de forrajes, permite mayor carga animal, sin dañar el rebrote y mayor eficiencia de cosecha forraje que el mono-especie.