Microbiological Quality of Ready-to-Eat Vegetables Collected in Mexico City: Occurrence of Aerobic-Mesophilic Bacteria, Fecal Coliforms, and Potentially Pathogenic Nontuberculous Mycobacteria

Abstract

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.

Isolation and Histopathological Changes Associated with Non-Tuberculous Mycobacteria in Lymph Nodes Condemned at a Bovine Slaughterhouse

“…Therefore, our findings require further molecular analyses to support species identification. Nevertheless, the species of NTM reported here agree with those previously reported in Mexico in human lungs [ 25 , 26 , 27 , 28 ], water [ 29 , 30 ], and salad samples [ 31 ].…”

High microbial loads found in minimally-processed sliced mushrooms from Italian market

“…Moreover, the surface of mushrooms is not favourable for microbial growth, due to the presence of a cuticle, and only after cutting there is an increase in the microbial loads, because of the nutrients released available for the microorganisms (Ragaert et al ., 2007 ). For minimally processed vegetables, there is a broad range of aerobic mesophilic and aerobic psychrotrophic loads in freshcut vegetables reported in the literature with values higher (De Oliveira et al ., 2011 , APC values of 9.4 log CFU/g in arangula, 9.3 log CFU/g in spring onion/parsley mixture and 9.0 log CFU/g in spinach), similar (Soriano et al ., 2000 , AMC ranging from 3.01-7.81 log CFU/g in 144 ready-to-eat lettuce samples; Valentin-Bon et al , 2008 , average AMC from 100 bagged lettuce and spinach mixes was 7 log CFU/g; Santos et al , 2012 , APC ranged from 4.65-8.48 log CFU/g in fresh-cut salads) or lower (Maistro et al , 2012 , AMC from 4.00-6.89 log CFU/g in six kinds of minimally processed vegetables with non-modified atmosphere packages; Cerna-Cortes et al , 2015 , AMC from 3.0 to 6.6 log CFU/g in ready-to-eat salads; Cardamone et al , 2015 , AMC between 5 and 7 log CFU/g in minimally processed leafy vegetables) than those found in precut sliced mushrooms.…”

Microbiological safety of ready‐to‐eat foods in low‐ and middle‐income countries: A comprehensive 10‐year (2009 to 2018) review

“…Ready‐to‐eat foods (RTEs) are foods consumed without any further processing or preparations. They could be traditionally or industrially processed, packaged, or unpackaged and are usually considered to comprise, mainly, the publicly vended foods consumed immediately or later (Cerna‐Cortes et al., ; FAO & WHO ; Von Holy & Makhoane, ). Similar to other regions, RTEs are widely consumed in low‐ and middle‐income countries (LMICs) due to ease of production, availability, affordability, and palatability (Al Mamun, Rahman, & Turin, ; Al Mamun, Rahman, & Turin, ; Mensah, Yeboah‐Manu, Owusu‐Darko, & Ablordey, ).…”