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Demand for fresh, convenient, minimally processed vegetables has led to an increase in the quantity and variety of products available to the consumer. Modified atmosphere packaging, in combination with refrigeration, is increasingly being employed as a mild preservation technique to ensure quality and storage-life. The fresh nature of these products, together with the mild processing techniques and subsequent storage conditions, have presented indigenous and pathogenic microorganisms with new ecosystems and potential infection vehicles; a number of outbreaks of foodborne disease being attributed to their consumption. Psychrotrophic pathogens and pathogens which are capable of maintaining an infectious potential under mild preservation regimes are of particular concern; Listeria monocytogenes, Aeromonas hydrophila and Clostridium botulinum being amongst the most notable. This review describes the processing, packaging and storage procedures involved in the production of minimally processed vegetables, and details their impact upon the survival and growth of associated pathogens. Gaps in our current understanding of the consequences of this novel technology for microbiological safety are highlighted.

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The oxidative stability of w3-rich oil from Camelina sativa and the storage stability of a camelina oilbased spread were evaluated. Camelina oil was more stable than fish oil and linseed oil, but less stable than sunflower, corn, sesame, and olive oils, indicated by measuring peroxide values (PV), r-anisidine values (AV), total oxidation values (Totox), thiobarbituric acid reactive substances (TBARS), conjugated diene levels (CD), and conjugated triene levels (CT) during storage at 65 °C for 16 d. The camelina oil-based spread had higher PV, AV, Totox, TBARS, CD, and CT than the sunflower spread but maintained adequate sensory quality for 16 wk of storage at 4 °C or 8 °C.

The survival and growth of Escherichia coli O157:H7 (ATCC 43888 and NCTC 12900) and Listeria monocytogenes (ATCC 19114 and NCTC 11994) during storage (4 and 8 degrees C) on ready-to-use (RTU) packaged vegetables (lettuce, swedes (rutabaga), dry coleslaw mix, soybean sprouts) were studied. The vegetables were sealed within oriented polypropylene packaging film, and modified atmospheres developed in packs during storage due to produce respiration. Survival and growth patterns were dependent on vegetable type, package atmosphere, storage temperature and bacterial strain. Populations of L. monocytogenes and E. coli O157:H7 increased (P<0.05, by 1.5 to 2.5 log cycles, depending on strain) during a 12-day storage period on shredded lettuce (8 degrees C). L. monocytogenes populations also increased (by approximately 1 log cycle) on packaged swedes, did not change significantly (P>0.05) in packages of soybean sprouts and decreased by approximately 1.5 log cycles (P<0.05) on coleslaw mix (8 degrees C). E. coli O157:H7 populations on packaged coleslaw and soybean sprouts increased (by 1.5 to 2.5 log cycles) up to day 5, but declined during subsequent storage (8 degrees C). On packaged swedes (8 degrees C), populations of E. coli O157:H7 strain ATCC 43888 increased (by approximately 1 log cycle) during storage, whereas populations of strain 12900 increased between days 2 and 5, and declined during subsequent storage. Reducing the storage temperature from 8 to 4 degrees C reduced the growth of L. monocytogenes and E. coli O157:H7 on packaged RTU vegetables. However, viable populations remained at the end of the storage period at 4 degrees C.

Aims: To establish the relative importance of the osmo-and cryoprotective compounds glycine betaine and carnitine, and their transporters, for listerial growth and survival, in foods and during infection. Methods and Results: A set of Listeria monocytogenes mutants with single, double and triple mutations in the genes encoding the principal betaine and carnitine uptake systems (gbu, betL and opuC, respectively) was used to determine the specific contribution of each transporter to listerial growth and survival. Food models were chosen to represent high-risk foods of plant and animal origin i.e. coleslaw and frankfurters, which have previously been linked to major human outbreaks of listeriosis. BALB/c mice were used as an in vivo model of infection. Interestingly, while betaine appeared to confer most protection in foods, the hierarchy of transporter importance differs depending on the food type: Gbu>BetL>OpuC for coleslaw, as opposed to Gbu>OpuC>BetL in frankfurters. By contrast in the animal model, OpuC and thus carnitine, appears to play the dominant role, with the remaining systems contributing little to the infection process. Conclusions: This study demonstrates that the individual contribution of each system appears dependent on the immediate environment. In foods Gbu appears to play the dominant role, while during infection OpuC is most important. Significance and Impact of the Study: It is envisaged that this information may ultimately facilitate the design of effective control measures specifically targeting this pathogen in foods and during infection.

Different packaging films and storage temperatures were used to establish a range of equilibrium modified atmospheres for storage of shredded carrots. Quality and storage-life of the packaged shredded carrots were determined using sensory evaluation, microbial counts, and a range of physical tests. Minimal processing steps such as peeling and shredding caused physical damage, physiological stress, and enhanced microbial growth, leading to a reduced shelf life when compared to the whole vegetable. A P-plus microporous film (CO2 permeability of 29103mL.m 2.d 1.atm 1) was the most suitable for the storage of shredded carrots. Findings indicated that deterioration in these products was triggered by the depletion of oxygen more than by the rise in carbon dioxide.

Polyphenol Oxidase from Apple (Malus domestica Borkh. cv Bramley's Seedling): Purification Strategies and Characterization was 30 °C and the enzyme had residual activity of greater than 50% during storage for 72 h at 20 °C to 30 °C and was 30 °C and the enzyme had residual activity of greater than 50% during storage for 72 h at 20 °C to 30 °C and was 30 °C and the enzyme had residual activity of greater than 50% during storage for 72 h at 20 °C to 30 °C and was 30 °C and the enzyme had residual activity of greater than 50% during storage for 72 h at 20 °C to 30 °C and for 24 h at 40 °C to 50 °C.Of the substrates tested, activity was greatest with 4-methylcatechol followed by for 24 h at 40 °C to 50 °C. Of the substrates tested, activity was greatest with 4-methylcatechol followed by for 24 h at 40 °C to 50 °C. Of the substrates tested, activity was greatest with 4-methylcatechol followed by for 24 h at 40 °C to 50 °C. Of the substrates tested, activity was greatest with 4-methylcatechol followed by for 24 h at 40 °C to 50 °C. Of the substrates tested, activity was greatest with 4-methylcatechol followed by catechol, pyrogallol, and (-)-epicatechin. The most effective inhibitors tested were sodium metabisulfite and catechol, pyrogallol, and (-)-epicatechin. The most effective inhibitors tested were sodium metabisulfite and catechol, pyrogallol, and (-)-epicatechin. The most effective inhibitors tested were sodium metabisulfite and catechol, pyrogallol, and (-)-epicatechin. The most effective inhibitors tested were sodium metabisulfite and catechol, pyrogallol, and (-)-epicatechin. The most effective inhibitors tested were sodium metabisulfite and ascorbic acid. ascorbic acid. ascorbic acid. ascorbic acid. ascorbic acid.