Microbiological Quality of Bagged Cut Spinach and Lettuce Mixes

Division of Microbiology, United States Food and Drug Administration, College Park, Maryland 20740, USA.
Applied and Environmental Microbiology (Impact Factor: 3.67). 03/2008; 74(4):1240-2. DOI: 10.1128/AEM.02258-07
Source: PubMed


Analysis of 100 bagged lettuce and spinach samples showed mean total bacterial counts of 7.0 log(10) CFU/g and a broad range of < 4 to 8.3 log10 CFU/g. Most probable numbers (MPN) of > or = 11,000/g coliforms were found in 55 samples, and generic Escherichia coli bacteria were detected in 16 samples, but no E. coli count exceeded 10 MPN/g.

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    • "However, no clear phenotype has been found to strongly differentiate those groups, raising questions on the mechanisms that led to their formation and more generally on the nature of the differences in bacterial population structures. Low levels of non-pathogenic E. coli are often associated with vegetables after anthropic or natural contaminations , suggesting that interactions between E. coli and agricultural plants are not uncommon (Ibenyassine et al., 2007; Rai and Tripathi, 2007; Ilic et al., 2008; Valentin-Bon et al., 2008; Mandrell, 2009; Caponigro et al., 2010; Oliveira et al., 2010). In the light of past outbreaks linked with the ingestion of vegetables contaminated with enteric pathogens such as Salmonella enterica, E. coli O157:H7, or more recently E. coli O104:H4 (Rohde et al., 2011), it has been suggested that plants could be common vectors and even additional secondary "
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