Microbiological Quality of Ready-to-Eat Vegetables Collected in Mexico City: Occurrence of Aerobic-Mesophilic Bacteria, Fecal Coliforms, and Potentially Pathogenic Nontuberculous Mycobacteria.
The aims of this study were to evaluate the microbiological quality and the occurrence of nontuberculous mycobacteria (NTM) in a variety of salads and sprouts from supermarkets and street vendors in Mexico City. Aerobic-mesophilic bacteria (AMB) were present in 100% of RTE-salads samples; 59% of samples were outside guidelines range (>5.17 log10 CFU per g). Although fecal coliforms (FC) were present in 32% of samples, only 8% of them exceeded the permissible limit (100 MPN/g). Regarding the 100 RTE-sprouts, all samples were also positive for AMB and total coliforms (TC) and 69% for FC. Seven NTM species were recovered from 7 salad samples; they included three M. fortuitum, two M. chelonae, one M. mucogenicum, and one M. sp. Twelve RTE-sprouts samples harbored NTM, which were identified as M. porcinum (five), M. abscessus (two), M. gordonae (two), M. mucogenicum (two), and M. avium complex (one). Most RTE-salads and RTE-sprouts had unsatisfactory microbiological quality and some harbored NTM associated with illness. No correlation between the presence of coliforms and NTM was found. Overall, these results suggest that RTE-salads and RTE-sprouts might function as vehicles for NTM transmission in humans; hence, proper handling and treatment before consumption of such products might be recommendable.
Departamento de Microbiologia, Escuela Nacional de Ciencias Biologicas-Instituto Politecnico Nacional, Prolongacion Carpio y Plan de Ayala S/N, Colonia Casco de Santo Tomas, Delegacion Miguel Hidalgo, 11340 Mexico, DF, Mexico.
Jorge Francisco
JF
Cerna-Cortes
Departamento de Microbiologia, Escuela Nacional de Ciencias Biologicas-Instituto Politecnico Nacional, Prolongacion Carpio y Plan de Ayala S/N, Colonia Casco de Santo Tomas, Delegacion Miguel Hidalgo, 11340 Mexico, DF, Mexico.
Nancy
N
Leon-Montes
Departamento de Microbiologia, Escuela Nacional de Ciencias Biologicas-Instituto Politecnico Nacional, Prolongacion Carpio y Plan de Ayala S/N, Colonia Casco de Santo Tomas, Delegacion Miguel Hidalgo, 11340 Mexico, DF, Mexico.
Ana Laura
AL
Cortes-Cueto
Departamento de Microbiologia, Escuela Nacional de Ciencias Biologicas-Instituto Politecnico Nacional, Prolongacion Carpio y Plan de Ayala S/N, Colonia Casco de Santo Tomas, Delegacion Miguel Hidalgo, 11340 Mexico, DF, Mexico.
Laura P
LP
Salas-Rangel
Departamento de Inmunobioquimica, Torre de Investigación, Instituto Nacional de Perinatología Isidro Espinosa de los Reyes (INPer), Montes Urales 800, Colonia Lomas de Virreyes, 11000 Mexico, DF, Mexico.
Addy Cecilia
AC
Helguera-Repetto
Departamento de Epidemiologia y Bioestadistica, Centro de Investigación y de Educación Continua (CENINVEC), Oyameles 30, Colonia La Perla, 57820 Ciudad Nezahualcóyotl, MEX, Mexico.
Daniel
D
Lopez-Hernandez
Departamento de Microbiologia, Escuela Nacional de Ciencias Biologicas-Instituto Politecnico Nacional, Prolongacion Carpio y Plan de Ayala S/N, Colonia Casco de Santo Tomas, Delegacion Miguel Hidalgo, 11340 Mexico, DF, Mexico.
Sandra
S
Rivera-Gutierrez
Departamento de Microbiologia, Escuela Nacional de Ciencias Biologicas-Instituto Politecnico Nacional, Prolongacion Carpio y Plan de Ayala S/N, Colonia Casco de Santo Tomas, Delegacion Miguel Hidalgo, 11340 Mexico, DF, Mexico.
Elizabeth
E
Fernandez-Rendon
Departamento de Microbiologia, Escuela Nacional de Ciencias Biologicas-Instituto Politecnico Nacional, Prolongacion Carpio y Plan de Ayala S/N, Colonia Casco de Santo Tomas, Delegacion Miguel Hidalgo, 11340 Mexico, DF, Mexico.
Jorge Alberto
JA
Gonzalez-y-Merchand
D004755:Enterobacteriaceae / Q000302:isolation & purification / Q000472:pathogenicity; D005516:Food Microbiology; D006090:Gram-Negative Bacteria / Q000145:classification / Q000302:isolation & purification* / Q000472:pathogenicity; D006801:Humans; D008800:Mexico; D009170:Nontuberculous Mycobacteria / Q000302:isolation & purification* / Q000472:pathogenicity; D014675:Vegetables / Q000382:microbiology*