Effect of processing and storage conditions on the microbiological quality of minimally processed vegetables

Abstract

The microbiological contamination of minimally processed vegetables was measured before and after processing and at different times and storage temperatures (5 and 10 days at 4 and 20°C). To evaluate the efficacy of the overall process the water used for washing and rinsing the vegetables during the various phases of the operation were also examined. Thanks to the high quality of the vegetables at origin, simple chlorine treatment was sufficient to achieve a satisfactory reduction in coliforms, Escherichia coli, coliphages and saprophytic flora, thus ensuring that all of the freshly packed samples conformed to reference standards and guidelines. This conformity was maintained when the storage instructions indicated on the package (4°C for 5 days) were followed. However, the persistence of faecal indicators after treatment suggested a potential risk of infection that could increase if the original contamination was higher. Microbiological examination of the water used for preliminary washing and for rinsing was seen to be useful in the assessment of the safety of the vegetables, at origin and after processing. The advantage of choosing coliphages for such monitoring is that they are indicators of viral contamination that can be measured rapidly. Critical points to be checked during the process are the levels of residual chlorine remaining in the washing tanks and the storage temperatures.

Combined effects of natural additives and modified atmosphere on quality of fresh cut peaches

“…In Brazil, there is no specific legislation for the total counts of mesophilic cells permitted on fresh cut fruits and vegetables, but some standards or recommendations can be used for comparison. The regulations of France and Germany established that ready to eat vegetables must have the maximum of 7.7 log CFU g -1 of total count of aerobic mesophiles (LEGNANI;LEONI, 2004). In this study, the treatments T2 on the ninth day showed total count of aerobic mesophilic cells above 7.7 log CFU g-1, which is not in accordance with the recommendation of France and Germany.…”

The evaluation of the microbial safety of fresh ready-to-eat vegetables produced by different technologies in Italy

“…This processing, in most cases, is inadequate in ensuring sterility or even microbiological stability. The initial quality and subsequent handling of these products appear to strongly influence the microbiology safety and shelf life (Legnani and Leoni 2004). The factors that may affect the occurrence of pathogen contaminations in vegetables include poor agricultural water quality, the use of manure as a fertilizer and the incorrect application of Good Manufacturing Practice (GMP) and Hazard Analysis and Critical Control Point (HACCP) systems during production, processing, packaging and distribution.…”

Microbiological quality of tomatoes and peppers produced under the good agricultural practices protocol AGRO 2-1 & 2-2 in Crete, Greece

“…Although they are colonized mainly by saprophytes and plant pathogens (Ligoxigakis, Fragkiadakis, Manganaris, Vakalounakis, & Thanassoulopoulos, 2002;Vakalounakis & Fragkiadakis, 1999;Vakalounakis, Wang, Fragkiadakis, Skaracis, & Li, 2004), they can also carry human pathogens (Listeria monocytogenes, Escherichia coli etc.) that occasionally cause outbreaks of foodborne illness (Beuchat, 1996;Garrett et al, 2003;Legnani & Leoni, 2004).…”