Electricity-free amplification and visual detection of Cronobacter species in powdered infant formula

Abstract

Due to the lack of electricity and thermostatic instruments in certain settings for convenient detection of Cronobacter species in powdered infant formula (PIF), a novel investigation was conducted to establish an electricity-free visual detection system for rapid detection of Cronobacter species in PIF. This system included a portable electricity-free heater that could use the exothermic reaction of calcium oxide and water and 3 kinds of phase change materials to supply 3 constant temperatures for immunomagnetic separation, DNA extraction, and loop-mediated isothermal amplification assay. Meanwhile, the amplified reaction combined with hydroxynaphthol blue could achieve rapid visual detection. Primers designed based on the 16S-23S ribosomal RNA internal transcribed spacer were used in loop-mediated isothermal amplification to specifically monitor Cronobacter species, and the detection limit can reach 4.2 × 10 2 cfu/g in PIF by an electricity-free heater in 2 h 30 min. Moreover, 2 h of pre-enrichment was necessary when the level of the PIF samples with Cronobacter spp. was 10 0 cfu/g. The stability of the system was evaluated in ambient temperature at 4°C, 25°C, and 37°C. The results suggested that the electricity-free heater can maintain 3 constant temperatures to support different processes. Therefore, this amplification and visual system is applicable for use in many fields for rapid and specific detection of Cronobacter species in PIF.

Uma abordagem dos ensaios in vitro para estimar a absorção dos minerais em fórmulas infantis

“…Atualmente, a segurança da FI é garantida por rigorosas legislações, por um controle de qualidade que emprega métodos analíticos bem estabelecidos e por novos estudos que trazem soluções práticas para minimizar possíveis incidentes, principalmente os microbiológicos. Estes incidentes podem afetar as características organolépticas, influenciando o consumidor e diminuindo a credibilidade em relação à qualidade do produto (Fei et al, 2020;Fioravanti et al, 2020a;Fu et al, 2020;Pires et al, 2020;Li et al, 2019). Para prevenir cada vez mais estes incidentes, os regulamentos técnicos de FI para lactentes e produtos lácteos são delineados por padrões internacionais elaborados pela Comissão do Codex Alimentarius ou por padrões específicos elaborados principalmente pela União Europeia e pelos seguintes países: Estados Unidos, China, Austrália e Nova Zelândia (Poitevin, 2016).…”

An aptamer-exonuclease III (Exo III)–assisted amplification-based lateral flow assay for sensitive detection of Escherichia coli O157:H7 in milk

“…The incidents of foodborne diseases increase every year despite extensive efforts to combat different foodborne pathogens (Fu et al, 2020;Jiang et al, 2020). Among all foodborne pathogens, Escherichia coli O157:H7 is considered to be one of the most focused (Yang et al, 2020).…”

A novel smartphone-based colorimetric aptasensor for on-site detection of Escherichia coli O157:H7 in milk

“…Escherichia coli O157:H7, one of the acute foodborne pathogens, can contaminate multiple foods and may cause intussusception (Cha et al, 2019) or diarrhearelated hemolytic uremic syndromes (Ko et al, 2016, Kintz et al, 2019. Traditional diagnostic methods for foodborne pathogens depend on sending samples to a laboratory and culturing in a centralized facility, which cannot meet the demand of on-site testing (Pan et al, 2018;Fu et al, 2020;Jiang et al, 2020). Thus, under the circumstance of limited resources, a novel, simple, rapid on-site testing platform is important to reduce the risk of infection of E. coli O157:H7 in UHT milk.…”