@article{page_carter-ogden_lee_perez-diaz_2022, title={Genome Sequences for Levilactobacillus brevis Autochthonous to Commercial Cucumber Fermentations}, ISSN={["2576-098X"]}, DOI={10.1128/mra.00029-22}, abstractNote={
            We report the whole-genome sequences, along with annotations, of 11
            Levilactobacillus brevis
            isolates from commercial cucumber fermentations performed in North Carolina (
            n
            = 9) and Minnesota (
            n
            = 2), USA.
          }, journal={MICROBIOLOGY RESOURCE ANNOUNCEMENTS}, author={Page, Clinton A. and Carter-Ogden, Ruby A. and Lee, Alice M. and Perez-Diaz, Ilenys M.}, year={2022}, month={Apr} }
 @article{rothwell_zhai_pagan-medina_perez-diaz_2022, title={Growth of gamma-Proteobacteria in Low Salt Cucumber Fermentation Is Prevented by Lactobacilli and the Cover Brine Ingredients}, ISSN={["2165-0497"]}, DOI={10.1128/spectrum.01031-21}, abstractNote={
            While the abundance of specific ɣ-proteobacteria species varies among vegetable type, several harbor
            Enterobacteriaceae
            and
            Pseudomonadaceae
            that benefit the plant system. It is documented that such bacterial populations decrease in density early in vegetable fermentations.
          }, journal={MICROBIOLOGY SPECTRUM}, author={Rothwell, Madison A. R. and Zhai, Yawen and Pagan-Medina, Christian G. and Perez-Diaz, Ilenys M.}, year={2022}, month={May} }
 @article{perez-diaz_medina_page_johanningsmeier_daughtry_moeller_2022, title={Prevention of microbes-induced spoilage in sodium chloride-free cucumber fermentations employing preservatives}, ISSN={["1750-3841"]}, DOI={10.1111/1750-3841.16345}, abstractNote={AbstractThis study evaluated preservatives to stabilize sodium chloride (NaCl)–free‐cucumber fermentations. The brining of air‐purged laboratory cucumber fermentations with 100.0 mM calcium chloride (CaCl2) and 25.0 mM acetic acid resulted in immediate rises in pH, the chemical reduction of the medium, and malodors. Supplementation with 3.0 mM sodium benzoate or 3.0 mM potassium sorbate enabled a decline in pH, a continuous oxidative state of the medium, and delayed rising pH spoilage. However, lactic and acetic acids eventually disappeared in fermentations supplemented with preservatives. The amount of preservatives needed to suppress growth of brined‐cucumber‐spoilage microbes was determined in Fermented Cucumber Juice Medium (FCJM). Supplementation of FCJM with 10.0 mM sodium benzoate was inhibitory for the spoilage yeasts, Issatchenkia occidentalis and Pichia manshurica, and the lactobacilli, Lentilactobacillus buchneri and Lentilactobacillus parafarraginis, but not of Zygosaccharomyces globiformis. Potassium sorbate inhibited the spoilage yeasts at 15.0 mM in FCJM but not the lactobacilli. Supplementation of FCJM with 20.0 mM fumaric acid had a bactericidal effect on the spoilage‐associated lactobacilli. As expected, NaCl‐free‐commercial cucumber fermentations brined with 100 mM CaCl2, no acetic acid, and 6 mM potassium sorbate resulted in complete fermentations, but supported rising pH, microbially induced spoilage during long‐term storage. Post‐fermentation supplementation with 12 mM sodium benzoate, 10 mM fumaric acid, a combination of the two, or 10 mM fumaric acid and 2 mM AITC prevented microbial activity during long‐term bulk storage.}, journal={JOURNAL OF FOOD SCIENCE}, author={Perez-Diaz, Ilenys M. and Medina, Eduardo and Page, Clinton A. and Johanningsmeier, Suzanne D. and Daughtry, Katheryne V and Moeller, Lisa}, year={2022}, month={Oct} }
 @article{little_cruz-martinez_st fort_pagan-medina_page_perez-perez_taveirne_lee_arroyo-gonzalez_santiago-ortiz_et al._2022, title={Vegetable fermentations brined with low salt for reclaiming food waste}, ISSN={["1750-3841"]}, DOI={10.1111/1750-3841.16084}, abstractNote={AbstractFermentation of eight vegetables was studied as an alternative for reclamation of surplus volumes. Fermentation performance was predicted by comparing the amounts of acid that could be produced from the intrinsic sugar content with that buffered by the fresh vegetable matrices prior to reaching an inhibitory pH for fermentative microbes (3.30). Native fermentations were brined with 345.0 mM sodium chloride, 40.0 mM calcium chloride, 6.0 mM potassium sorbate, and vinegar to adjust the initial pH to 4.70. High‐performance liquid chromatography analysis, pH, and carbon dioxide measurements and spiral plating on selective media were employed to monitor the progress of fermentations. The average colony counts for yeast and/or molds and Enterobacteriaceae declined to undetectable levels from 3.6 ± 1.5 log CFU/ml within 7 days of fermentation. The fermentation of sugars produced lactic, acetic, succinic, and/or malic acids, and ethanol. As predicted, the fermentation of vegetables with low sugar content, such as broccoli, green leaf lettuce, and green pea proceeded to completion. The fermentation of vegetables with a moderate sugar content, such as green bell pepper, red ripened tomato, and green bean were incomplete at pH 3.1 ± 0.2. The fermentation of high sugar vegetables including sweet potato and corn were expected and observed to be incomplete. It is concluded that the intrinsic sugar content and buffer capacity of surplus vegetables are relevant parameters in obtaining complete fermentations.}, journal={JOURNAL OF FOOD SCIENCE}, author={Little, Connor and Cruz-Martinez, Viviana and St Fort, Datricia Pearl and Pagan-Medina, Christian and Page, Clinton A. and Perez-Perez, Yobet and Taveirne, Michael E. and Lee, Alice M. and Arroyo-Gonzalez, Nancy and Santiago-Ortiz, Cariluz and et al.}, year={2022}, month={Mar} }
 @article{perez-diaz_johanningsmeier_anekella_pagan-medina_mendez-sandoval_arellano_price_daughtry_borges_bream_et al._2021, title={Genotypic and phenotypic diversity among Lactobacillus plantarum and Lactobacillus pentosus isolated from industrial scale cucumber fermentations}, volume={94}, ISSN={["1095-9998"]}, DOI={10.1016/j.fm.2020.103652}, abstractNote={The Lactobacillus plantarum and Lactobacillus pentosus genotypes existing in industrial-scale cucumber fermentations were defined using rep-PCR-(GTG)5. The ability of each genotype to ferment cucumbers under various conditions was evaluated. Rep-PCR-(GTG)5 was the technique capable of illustrating the most intraspecies discrimination compared to the sequencing of housekeeping genes (recA, dnaK, pheS and rpoA), MLST and RAPD with primers LP1, OPL5, M14 and COC. Ten genotypic clusters were defined for the 199 L. pentosus tested and three for the 17 L. plantarum clones. The ability of the 216 clones genotyped and 37 additional cucumber fermentation isolates, of the same species, to rapidly decrease the pH of cucumber juice medium under various combinations of sodium chloride (0 or 6%), initial pH (4.0 or 5.2) and temperatures (15 or 30 °C) was determined using a fractional factorial screening design. A reduced fermentation ability was observed for the L. plantarum strains as compared to L. pentosus, except for clone 3.2.8, which had a ropy phenotype and aligned to genotypic cluster A. L. pentosus strains belonging to three genotypic clusters (B, D and J) were more efficient in cucumber juice fermentation as compared to most L. plantarum strains. This research identified three genetically diverse L. pentosus strains and one L. plantarum as candidates for starter cultures for commercial cucumber fermentations.}, journal={FOOD MICROBIOLOGY}, author={Perez-Diaz, Ilenys M. and Johanningsmeier, Suzanne D. and Anekella, Kartheek and Pagan-Medina, Christian G. and Mendez-Sandoval, Lesley and Arellano, Consuelo and Price, Robert and Daughtry, Katheryne V and Borges, Michelle and Bream, Chloe and et al.}, year={2021}, month={Apr} }
 @article{zhai_perez-diaz_2021, title={Identification of potential causative agents of the CO2-mediated bloater defect in low salt cucumber fermentation}, volume={344}, ISSN={["1879-3460"]}, DOI={10.1016/j.ijfoodmicro.2021.109115}, abstractNote={Development of bloater defect in cucumber fermentations is the result of carbon dioxide (CO2) production by the indigenous microbiota. The amounts of CO2 needed to cause bloater defect in cucumber fermentations brined with low salt and potential microbial contributors of the gas were identified. The carbonation of acidified cucumbers showed that 28.68 ± 6.04 mM (12%) or higher dissolved CO2 induces bloater defect. The microbiome and biochemistry of cucumber fermentations (n = 9) brined with 25 mM calcium chloride (CaCl2) and 345 mM sodium chloride (NaCl) or 1.06 M NaCl were monitored on day 0, 2, 3, 5, 8, 15 and 21 using culture dependent and independent microbiological techniques and High-Performance Liquid Chromatography. Changes in pH, CO2 concentrations and the incidence of bloater defect were also followed. The enumeration of Enterobacteriaceae on Violet Red Bile Glucose agar plates detected a cell density of 5.2 ± 0.7 log CFU/g on day 2, which declined to undetectable levels by day 8. A metagenomic analysis identified Leuconostocaceae in all fermentations at 10 to 62%. The presence of both bacterial families in fermentations brined with CaCl2 and NaCl coincided with a bloater index of 24.0 ± 10.3 to 58.8 ± 23.9. The prevalence of Lactobacillaceae in a cucumber fermentation brined with NaCl with a bloater index of 41.7 on day 5 suggests a contribution to bloater defect. This study identifies the utilization of sugars and malic acid by the cucumber indigenous Lactobacillaceae, Leuconostocaceae and Enterobacteriaceae as potential contributors to CO2 production during cucumber fermentation and the consequent bloater defect.}, journal={INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY}, author={Zhai, Yawen and Perez-Diaz, Ilenys M.}, year={2021}, month={Apr} }
 @article{lu_perez-diaz_hayes_breidt_2020, title={Bacteriophages Infecting Gram-Negative Bacteria in a Commercial Cucumber Fermentation}, volume={11}, ISSN={["1664-302X"]}, DOI={10.3389/fmicb.2020.01306}, abstractNote={Cucumber fermentations are one of the most important vegetable fermentations in the United States. The fermentation is usually driven by lactic acid bacteria (LAB) indigenous to fresh cucumbers. But LAB are greatly outnumbered by many Gram-negative bacteria on fresh cucumbers, which may influence the growth of LAB and the incidence of bloater defect (hollow cavities formed inside fermented cucumbers) leading to serious economic loss to the pickle industry. Rapid elimination of Gram-negative bacteria is crucial to the dominance of LAB and the reduction of bloater defect in the fermentation. Various factors can affect the viability of Gram-negative bacteria in cucumber fermentation. Bacteriophages (phages) may be one of such factors. This study explored the abundance, diversity, and functional role of phages infecting Gram-negative bacteria in a commercial cucumber fermentation. Cover brine samples were taken from a commercial fermentation tank over a 30-day period. On day 1 and day 3 of the fermentation, 39 Gram-negative bacteria and 26 independent phages were isolated. Nearly 67% of Gram-negative bacterial isolates were susceptible to phage infection. Phage hosts include Enterobacter, Citrobacter, Escherichia, Pantoea, Serratia, Leclercia, Providencia, and Pseudomonas species. About 88% of the isolated phages infected the members in the family Enterobacteriaceae and 58% of phages infected Enterobacter species. Eight phages with unique host ranges were characterized. These phages belong to the Myoviridae, Siphoviridae, or Podoviridae family and showed distinct protein profiles and DNA fingerprints. The infectivity of a phage against Enterobacter cancerogenus was evaluated in cucumber juice as a model system. The phage infection at the multiplicity of infection 1 or 100 resulted in a 5-log reduction in cell concentration within 3 h and rapidly eliminated its host. This study revealed the abundance and variety of phages infecting Gram-negative bacteria, particularly Enterobacteriaceae, in the commercial cucumber fermentation, suggesting that phages may play an important role in the elimination of Gram-negative bacteria, thereby facilitating the dominance of LAB and minimizing bloater defect. To our knowledge, this is the first report on the ecology of phages infecting Gram-negative bacteria in commercial cucumber fermentations.}, journal={FRONTIERS IN MICROBIOLOGY}, author={Lu, Zhongjing and Perez-Diaz, Ilenys M. and Hayes, Janet S. and Breidt, Fred}, year={2020}, month={Jun} }
 @article{anekella_perez-diaz_2020, title={Characterization of robustLactobacillus plantarumandLactobacillus pentosusstarter cultures for environmentally friendly low-salt cucumber fermentations}, volume={85}, ISSN={["1750-3841"]}, DOI={10.1111/1750-3841.15416}, abstractNote={AbstractSeven candidates for starter cultures for cucumber fermentations belonging to the Lactobacillus pentosus and Lactobacillus plantarum species were characterized based on physiological features desired for pickling. The isolates presented variable carbohydrate utilization profile on API® 50CHL test strips. The L. pentosus strains were unable to utilize d‐xylose in MRS broth or the M medium. The lactobacilli were unable to produce histamine, tyramine, putrescine, and cadaverine in biogenic amine broth containing the necessary precursors. Production of d‐lactic acid by the lactobacilli, detected enzymatically, was stimulated by growth in MRS broth as compared to cucumber juice medium (CJM). The lactobacilli utilized malic acid in the malate decarboxylase medium. Exopolyssacharide biosynthesis related genes were amplified from the lactobacilli. A sugar type‐dependent‐ropy phenotype was apparent for all the cultures tested in MRS and CJM. The genes associated with bacteriocin production were detected in the lactobacilli, but not the respective phenotypes. The antibiotic susceptibility profile of the lactobacilli mimics that of other L. plantarum starter cultures. It is concluded that the lactobacilli strains studied here are suitable starter cultures for cucumber fermentation.}, number={10}, journal={JOURNAL OF FOOD SCIENCE}, author={Anekella, Kartheek and Perez-Diaz, Ilenys M.}, year={2020}, month={Oct}, pages={3487–3497} }
 @article{ucar_perez-diaz_dean_2020, title={Content of xylose, trehalose and L -citrulline in cucumber fermentations and utilization of such compounds by certain lactic acid bacteria ?}, volume={91}, ISSN={["1095-9998"]}, DOI={10.1016/j.fm.2020.103454}, abstractNote={This research determined the concentration of trehalose, xylose and l-citrulline in fresh and fermented cucumbers and their utilization by Lactobacillus pentosus, Lactobacillus plantarum, Lactobacillus brevis and Lactobacillus buchneri. Targeted compounds were measured by HPLC and the ability of the lactobacilli to utilize them was scrutinized in fermented cucumber juice. Fresh cucumber juice was supplemented with trehalose, xylose and l-citrulline to observed mixed culture fermentations. Changes in the biochemistry, pH and colony counts during fermentations were monitored. Trehalose, xylose and l-citrulline were detected in fermentations to15.51 ± 1.68 mM, a fresh cucumber sample at 36.05 mM and in fresh and fermented cucumber samples at 1.05 ± 0.63 mM, respectively. Most of the LAB tested utilized trehalose and xylose in FCJM at pH 4.7. l-citrulline was utilized by L. buchneri and produced by other LAB. l-citrulline (12.43 ± 2.3 mM) was converted to ammonia (14.54 ± 3.60 mM) and the biogenic amine ornithine (14.19 ± 1.07 mM) by L. buchneri at pH 4.7 in the presence of 0.5 ± 0.2 mM glucose enhancing growth by 0.5 log CFU/mL. The use of a mixed starter culture containing L. buchneri aided in the removal of l-citrulline and enhanced the fermentation stability. The utilization of l-citrulline by L. buchneri may be a cause of concern for the stability of cucumber fermentations at pH 3.7 or above. This study identifies the use of a tripartite starter culture as an enhancer of microbial stability for fermented cucumbers.}, journal={FOOD MICROBIOLOGY}, author={Ucar, Redife Aslihan and Perez-Diaz, Ilenys M. and Dean, Lisa L.}, year={2020}, month={Oct} }
 @article{zhai_perez-diaz_2020, title={Contribution of Leuconostocaceae to CO 2-mediated bloater defect in cucumber fermentation *}, volume={91}, ISSN={["1095-9998"]}, DOI={10.1016/j.fm.2020.103536}, abstractNote={Fermented cucumber bloater defect, caused by the accumulation of microbiologically produced carbon dioxide (CO2), creates significant economic losses for the pickling industry. The ability of Leuconostocaceae, indigenous to cucumber, to grow and produce CO2 during a fermentation and cause bloater defect was evaluated. Leuconostocaceae grew and produced over 40% CO2 in cucumber juice medium, used as a model for cucumber fermentation. The inoculation of Leuconostocaceae to 5 Log CFU/g in cucumber fermentations brined with 25 mM calcium chloride and 6 mM potassium sorbate resulted in no significant differences in bloater defect, colony counts from MRS and VRBG agar plates or the fermentation biochemistry; suggesting an inability of the inoculated bacterial species to prevail in the bioconversion. Acidified cucumbers were subjected to a fermentation inoculated with a Leuconostoc lactis starter culture after raising the pH to 5.9 ± 0.4. CO2 was produced in the acidified cucumber fermentations to 13.6 ± 3.5% yielding a bloater index of 21.3 ± 6.4; while 8.6 ± 0.8% CO2 and a bloater index of 5.2 ± 5.9 were observed in the non-inoculated control jars. Together the data collected demonstrate that Leuconostocaceae can produce enough CO2 to contribute to bloater defect, if not outcompeted by the leading lactic acid bacteria in a cucumber fermentation.}, journal={FOOD MICROBIOLOGY}, author={Zhai, Yawen and Perez-Diaz, Ilenys M.}, year={2020}, month={Oct} }
 @article{ucar_perez-diaz_dean_2020, title={Gentiobiose and cellobiose content in fresh and fermenting cucumbers and utilization of such disaccharides by lactic acid bacteria in fermented cucumber juice medium}, volume={8}, ISSN={["2048-7177"]}, DOI={10.1002/fsn3.1830}, abstractNote={Abstract}, number={11}, journal={FOOD SCIENCE & NUTRITION}, author={Ucar, Redife Aslihan and Perez-Diaz, Ilenys M. and Dean, Lisa L.}, year={2020}, month={Nov}, pages={5798–5810} }
 @article{franco_perez-diaz_connelly_diaz_2020, title={Isolation of Exopolysaccharide-Producing Yeast and Lactic Acid Bacteria from Quinoa (Chenopodium Quinoa) Sourdough Fermentation}, volume={9}, ISSN={["2304-8158"]}, DOI={10.3390/foods9030337}, abstractNote={Quinoa, a nutritional grain, can be used as an ingredient in gluten-free sourdoughs. This study characterizes quinoa flour spontaneous fermentation with emphasis in the isolation of exopolysaccharide (EPS) producer bacteria. Real, red and black grains were studied. Dough yield, microbiota composition and fermentation biochemistry were determined for a total of 36 quinoa flour fermentations. The fermentation biochemistry was monitored by high-performance liquid chromatography (HPLC) analysis, pH measurement and titratable acidity. Changes in the microbiota were monitored by plating on deMann Rogosa and Sharp 5 agar (MRS5) and yeast and mold agar (YMA) plates and with metagenetic analysis. The ability to produce exopolysaccharides was screened in selected lactic acid bacteria (LAB) isolates. Production of organic acids in the spontaneous fermentation dropped the pH to 4.0 ± 0.3. The community of presumptive LAB reached 8.37 ± 0.01 log colony forming units (CFU)/mL by day 8 of back-slopped fermentations. The microbiota was composed of Lactobacillus, Enterococcus, Leuconostoc, Lactococcus, Pediococcus and Weissella. P. pentosaceous, L. citreum and W. cibaria were able to produce EPS in a starch-rich medium. P. pentosaceous showed higher exopolysaccharide yield, rapid acidifying kinetics and was able to drop the dough broth pH to values below 4.0 and a positive fermentation quotient after 24 h of incubation. Therefore, the bacterium might be a potential candidate for quinoa sourdough production.}, number={3}, journal={FOODS}, author={Franco, Wendy and Perez-Diaz, Ilenys M. and Connelly, Lauren and Diaz, Joscelin T.}, year={2020}, month={Mar} }
 @article{perez-diaz_dicky_fitria_ravishankar_hayes_campbell_arritt_2020, title={Modulation of the bacterial population in commercial cucumber fermentations by brining salt type}, volume={128}, ISSN={["1365-2672"]}, DOI={10.1111/jam.14597}, abstractNote={Differences in the bacterial population of cucumber fermentations brined with no salt, 100 mmol l−1 (1·1%) calcium chloride (CaCl2) or 1·03 mol l−1 (6%) sodium chloride (NaCl) were studied.}, number={6}, journal={JOURNAL OF APPLIED MICROBIOLOGY}, author={Perez-Diaz, I. M. and Dicky, A. N. e and Fitria, R. and Ravishankar, N. and Hayes, J. and Campbell, K. and Arritt, F.}, year={2020}, month={Jun}, pages={1678–1693} }
 @article{perez-diaz_hayes_medina_webber_butz_dickey_lu_azcarate-peril_2019, title={Assessment of the non-lactic acid bacteria microbiota in fresh cucumbers and commercially fermented cucumber pickles brined with 6% NaCl}, volume={77}, ISSN={["1095-9998"]}, DOI={10.1016/j.fm.2018.08.003}, abstractNote={Limited documentation of the cucumber fermentation microbiome has impeded the understanding of the role of microbes on the quality of finished products. We characterized the microbiome of fresh and fermented cucumber samples using culture dependent and independent techniques, with an emphasis on the non-lactic acid bacteria (non-LAB) population. Insubstantial microbiome variations were observed among fresh cucumber types with Rhizobium (31.04%), Pseudomonas (14.08%), Pantoea (9.25%), Stenotrophomonas (6.83%), and Acinetobacter (6.5%) prevailing. The relative abundance of LAB remained below 0.4% and 4.0% on fresh cucumbers and day 3 of the fermentations brined with 6% sodium chloride, respectively. Fermentation cover brine samples collected on day 1 harbored Pseudomonas, Pantoea, Stenotrophomonas, Acinetobacter, Comamonas, Wautersiella, Microbacterium, Flavobacterium, Ochrobactrum and the Enterobacteriaceae, Citrobacter, Enterobacter and Kluyvera. Plate counts for presumptive Klebsiella and Pseudomonas from fermentation cover brine samples reached 2.80 ± 0.36 and 2.78 ± 0.83 log of CFU/mL, respectively, in 30% and 60% of the nine tanks scrutinized with selective media. Both genera were found in cover brine samples with pH values at 4.04 ± 0.15. We aim at elucidating whether the low relative abundance of non-LAB in commercial cucumber fermentations, in particular Pseudomonas and Enterobacteriaceae, impacts the quality of fermented cucumbers.}, journal={FOOD MICROBIOLOGY}, author={Perez-Diaz, Ilenys M. and Hayes, Janet S. and Medina, Eduardo and Webber, Ashlee M. and Butz, Natasha and Dickey, Allison N. and Lu, Zhongjing and Azcarate-Peril, Maria A.}, year={2019}, month={Feb}, pages={10–20} }
 @article{diaz_perez-diaz_messer_safferman_2018, title={Physical properties of NaCl-free cucumber fermentation cover brine containing CaCl2 and glycerin and apparent freezing injury of the brined fruits}, volume={42}, ISSN={["1745-4549"]}, DOI={10.1111/jfpp.13582}, abstractNote={Use of glycerin and CaCl₂ to reduce the freezing point and improve quality of bulk stored fermented cucumbers brined without NaCl, was explored. The incidence of pre‐freezing injury on the fruits, caused by deposition in tanks containing cushion brine prepared with 2.5% CaCl₂, was excluded by determining the liquid and fruits densities and buoyancy force. The NaCl‐free cover brine thermal properties and freezing point, and the frozen fruits water loss were determined to estimate freezing damage. Cover brines supplemented with 14.5% glycerin, 18% CaCl₂, or 14% glycerin and 5% CaCl₂ were needed to match the freezing point of the 6% NaCl cover brine, typically used for fermentation. Thermal properties of the NaCl‐free cover brine were insignificantly affected by temperature or composition. Water loss was the main freezing injury in brined cucumbers. Supplementation of CaCl₂ and/or glycerin in fermentation cover brines helped minimize fermented cucumbers water loss associated with freezing. PRACTICAL APPLICATIONS: This study presents an assessment of brine composition that can prolong processed pickle quality and bulk storage at temperatures below zero. Fermented cucumbers stored in cover brine containing 14.5 vol % glycerin, 18 wt % CaCl₂, or 14 vol % glycerin and 5 wt % CaCl₂ have a reduced freezing point, which theoretically extends the window for acceptable product quality. The use of 14% glycerin above the cover boards to reduce the freezing point and, consequently, ice formation on the surface of the open‐top tanks is to enable the removal of fermented fruits during winter with minimal tissue injury.}, number={4}, journal={JOURNAL OF FOOD PROCESSING AND PRESERVATION}, author={Diaz, Joscelin T. and Perez-Diaz, Ilenys M. and Messer, Nadya and Safferman, Steven I.}, year={2018}, month={Apr} }
 @misc{zhai_perez-diaz_diaz_2018, title={Viability of commercial cucumber fermentation without nitrogen or air purging}, volume={81}, ISSN={["0924-2244"]}, DOI={10.1016/j.tifs.2018.05.017}, abstractNote={Bloated cucumber defect, resulting from the accumulation of the biologically produced carbon dioxide (CO2) in the fruit, reduces yield and economic gains for the pickling industry worldwide. It was the aim of this review to identify commonalities among effective strategies to reduce bloater defect and determine the theoretical viability of commercial cucumber fermentations without bloater defect and/or purging. This article summarizes the known causes of fermented cucumber bloating defect, including sources of CO2, and the strategies developed to mitigate the production of the carbonic gas such as controlled fermentation, inoculation of selected starter cultures, cover brine acidification and reformulation and the application of air or nitrogen purging. It was understood that microbial activity during fermentation, cucumber tissue respiration, as well as the pressure in the fruits and fermentation tanks, ambient temperature and cover brine composition, impact the levels of dissolved CO2 in the system. Although the biological conversion of oxygen to CO2 reduces the cucumbers internal gas pressure, the dissipation of the gas from the tissue is reduced by brining. Once the gas accumulates in the cucumber tissue in concentrations high enough to displace it, the irreversible formation of hollow cavities or bloaters occurs. Residual CO2 is produced by acid-preserved cucumbers, presumably by tissue respiration, which results in the absence of bloating. Thus, microbial activity seems to contribute most of the CO2 needed for cucumbers to bloat. It is speculated that colonization of the internal cucumber tissue by indigenous microbes, in particular aerobic gram-negative bacteria, results in the localized production of CO2 causing bloating defect early in the fermentation. It is concluded that effective manipulation of the microbiota, reduction of dissolved oxygen levels and the use of adequately selected starter cultures may enable cucumber fermentations of acceptable quality without purging.}, journal={TRENDS IN FOOD SCIENCE & TECHNOLOGY}, author={Zhai, Yawen and Perez-Diaz, Ilenys M. and Diaz, Joscelin T.}, year={2018}, month={Nov}, pages={185–192} }
 @article{fan_breidt_price_perez-diaz_2017, title={Survival and Growth of Probiotic Lactic Acid Bacteria in Refrigerated Pickle Products}, volume={82}, ISSN={["1750-3841"]}, DOI={10.1111/1750-3841.13579}, abstractNote={Abstract}, number={1}, journal={JOURNAL OF FOOD SCIENCE}, author={Fan, Sicun and Breidt, Fred and Price, Robert and Perez-Diaz, Ilenys}, year={2017}, month={Jan}, pages={167–173} }
 @article{diaz_pérez-díaz_simunovic_sandeep_2017, title={Winterization strategies for bulk storage of cucumber pickles}, volume={212}, ISSN={0260-8774}, url={http://dx.doi.org/10.1016/j.jfoodeng.2017.03.027}, DOI={10.1016/j.jfoodeng.2017.03.027}, abstractNote={Cucumbers are commercially fermented and stored in bulk in outdoor open top fiberglass tanks. During winter, snow and ice that accumulates around and on top of tanks influence heat transfer in an unpredictable manner, often compromising quality. This study evaluates the performance of inexpensive and resilient fermentation tank insulation and provides an estimate of heat loss associated with strategies for storage and preservation of fermented cucumbers during winter. Three insulation configurations were explored: conical top-cover, flat top-cover, and perimeter insulation. Changes in temperature during storage were experimentally studied in different tank configurations. A mathematical model was developed to simulate temperature profiles and heat loss in an idealized fermentation/storage vessel. Comparisons of the insulated tank configurations suggested a significant difference in temperature between a flat cover and uncovered tank when exposed to temperatures characteristic of the spring season in Pinconning, MI.}, journal={Journal of Food Engineering}, publisher={Elsevier BV}, author={Diaz, Joscelin T. and Pérez-Díaz, Ilenys M. and Simunovic, Josip and Sandeep, K.P.}, year={2017}, month={Nov}, pages={12–17} }
 @article{perez-diaz_mcfeeters_moeller_johanningsmeier_hayes_fornea_rosenberg_gilbert_custis_beene_et al._2015, title={Commercial Scale Cucumber Fermentations Brined with Calcium Chloride Instead of Sodium Chloride}, volume={80}, ISSN={["1750-3841"]}, DOI={10.1111/1750-3841.13107}, abstractNote={Abstract}, number={12}, journal={JOURNAL OF FOOD SCIENCE}, author={Perez-Diaz, I. M. and McFeeters, R. F. and Moeller, L. and Johanningsmeier, S. D. and Hayes, J. and Fornea, D. S. and Rosenberg, L. and Gilbert, C. and Custis, N. and Beene, K. and et al.}, year={2015}, month={Dec}, pages={M2827–M2836} }
 @article{caldwell_pérez-díaz_sandeep_simunovic_harris_osborne_hassan_2015, title={Mitochondrial DNA Fragmentation as a Molecular Tool to Monitor Thermal Processing of Plant-Derived, Low-Acid Foods, and Biomaterials}, volume={80}, ISSN={0022-1147}, url={http://dx.doi.org/10.1111/1750-3841.12937}, DOI={10.1111/1750-3841.12937}, abstractNote={Abstract}, number={8}, journal={Journal of Food Science}, publisher={Wiley}, author={Caldwell, Jane M. and Pérez-Díaz, Ilenys M. and Sandeep, KP and Simunovic, Josip and Harris, Keith and Osborne, Jason A. and Hassan, Hosni M.}, year={2015}, month={Jul}, pages={M1804–M1814} }
 @article{breidt_medina_wafa_perez-diaz_franco_huang_johanningsmeier_kim_2013, title={Characterization of Cucumber Fermentation Spoilage Bacteria by Enrichment Culture and 16S rDNA Cloning}, volume={78}, ISSN={["1750-3841"]}, DOI={10.1111/1750-3841.12057}, abstractNote={Abstract}, number={3}, journal={JOURNAL OF FOOD SCIENCE}, author={Breidt, Fred and Medina, Eduardo and Wafa, Doria and Perez-Diaz, Ilenys and Franco, Wendy and Huang, Hsin-Yu and Johanningsmeier, Suzanne D. and Kim, Jae Ho}, year={2013}, month={Mar}, pages={M470–M476} }
 @article{lu_breidt_perez-diaz_2013, title={Development of an Effective Treatment for A 5-Log Reduction of Escherichia coli in Refrigerated Pickle Products}, volume={78}, ISSN={["0022-1147"]}, DOI={10.1111/j.1750-3841.2012.02968.x}, abstractNote={Abstract}, number={2}, journal={JOURNAL OF FOOD SCIENCE}, author={Lu, Huiying J. and Breidt, Frederick, Jr. and Perez-Diaz, Ilenys}, year={2013}, month={Feb}, pages={M264–M269} }
 @article{franco_perez-diaz_2013, title={Microbial interactions associated with secondary cucumber fermentation}, volume={114}, ISSN={["1365-2672"]}, DOI={10.1111/jam.12022}, abstractNote={To evaluate the interaction between selected yeasts and bacteria and associate their metabolic activity with secondary cucumber fermentation.}, number={1}, journal={JOURNAL OF APPLIED MICROBIOLOGY}, author={Franco, W. and Perez-Diaz, I. M.}, year={2013}, month={Jan}, pages={161–172} }
 @article{perez-diaz_2013, title={Putative and Unique Gene Sequence Utilization for the Design of Species Specific Probes as Modeled by Lactobacillus plantarum}, volume={66}, ISSN={["1432-0991"]}, DOI={10.1007/s00284-012-0265-6}, abstractNote={The concept of utilizing putative and unique gene sequences for the design of species specific probes was tested. The abundance profile of assigned functions within the Lactobacillus plantarum genome was used for the identification of the putative and unique gene sequence, csh. The targeted gene (csh) was used as the template for PCR amplification and construction of a non-radioactive DIG labeled probe. The csh derived probe aided in the preliminary and rapid identification of L. plantarum from mixed cultures by colony hybridization. The method described here for the rapid identification of L. plantarum can also be applied for the rapid detection of other bacteria if a unique gene sequence can be identified from its complete genome sequence.}, number={3}, journal={CURRENT MICROBIOLOGY}, author={Perez-Diaz, Ilenys M.}, year={2013}, month={Mar}, pages={266–270} }
 @article{franco_perez-diaz_johanningsmeier_mcfeeters_2012, title={Characteristics of Spoilage-Associated Secondary Cucumber Fermentation}, volume={78}, ISSN={["1098-5336"]}, DOI={10.1128/aem.06605-11}, abstractNote={ABSTRACT}, number={4}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Franco, Wendy and Perez-Diaz, Ilenys M. and Johanningsmeier, Suzanne D. and McFeeters, Roger F.}, year={2012}, month={Feb}, pages={1273–1284} }
 @article{franco_perez-diaz_2012, title={Development of a Model System for the Study of Spoilage Associated Secondary Cucumber Fermentation during Long-Term Storage}, volume={77}, ISSN={["1750-3841"]}, DOI={10.1111/j.1750-3841.2012.02845.x}, abstractNote={Abstract:  Calcium chloride fermentations represent an alternative to reduce chloride concentrations in the wastewaters generated from commercial cucumber fermentations, currently performed in cover brine solutions containing 6% to 12% sodium chloride. However, preliminary attempts to commercially ferment the cucumbers in the presence of oxygen led to the development of a secondary cucumber fermentation or spoilage. The development of cucumber secondary fermentation has also been occasionally reported by processors using cover brine solutions containing sodium chloride. This study focused on the development of a model system to characterize CaCl2 and NaCl secondary cucumber fermentations under conditions similar to those present on the commercial scale. Cucumber fruits mixed with cover brine solutions, containing 100 mM CaCl2 or 1.03 M NaCl, and 25 mM acetic acid, were fermented in 2 L fermentation vessels subjected to air‐purging at a rate of 5 mL/min. Microorganisms and selected biochemical changes detected in the experimental cucumber fermentations had been previously observed in commercial spoilage samples, suggesting the successful reproduction of the secondary fermentation in the laboratory. Experimental secondary fermentations were characterized by the rapid oxidation of the lactic acid produced during the primary fermentation, which, in turn, increased pH. Lactic acid disappearance seemed to be the result of yeast metabolism that also led to the chemical reduction of the environment to levels at which other bacteria could become established and produce butyric, propionic, and acetic acids. This model system will be applied for the identification of strategies to prevent the initiation of the cucumber secondary fermentation and reduce economic losses in the pickling industry.}, number={10}, journal={JOURNAL OF FOOD SCIENCE}, author={Franco, Wendy and Perez-Diaz, Ilenys M.}, year={2012}, month={Oct}, pages={M586–M592} }
 @article{johanningsmeier_franco_perez-diaz_mcfeeters_2012, title={Influence of Sodium Chloride, pH, and Lactic Acid Bacteria on Anaerobic Lactic Acid Utilization during Fermented Cucumber Spoilage}, volume={77}, ISSN={["1750-3841"]}, DOI={10.1111/j.1750-3841.2012.02780.x}, abstractNote={Abstract:  Cucumbers are preserved commercially by natural fermentations in 5% to 8% sodium chloride (NaCl) brines. Occasionally, fermented cucumbers spoil after the primary fermentation is complete. This spoilage has been characterized by decreases in lactic acid and a rise in brine pH caused by microbial instability. Objectives of this study were to determine the combined effects of NaCl and pH on fermented cucumber spoilage and to determine the ability of lactic acid bacteria (LAB) spoilage isolates to initiate lactic acid degradation in fermented cucumbers. Cucumbers fermented with 0%, 2%, 4%, and 6% NaCl were blended into slurries (FCS) and adjusted to pH 3.2, 3.8, 4.3, and 5.0 prior to centrifugation, sterile‐filtration, and inoculation with spoilage organisms. Organic acids and pH were measured initially and after 3 wk, 2, 6, 12, and 18 mo anaerobic incubation at 25 °C. Anaerobic lactic acid degradation occurred in FCS at pH 3.8, 4.3, and 5.0 regardless of NaCl concentration. At pH 3.2, reduced NaCl concentrations resulted in increased susceptibility to spoilage, indicating that the pH limit for lactic acid utilization in reduced NaCl fermented cucumbers is 3.2 or lower. Over 18 mo incubation, only cucumbers fermented with 6% NaCl to pH 3.2 prevented anaerobic lactic acid degradation by spoilage bacteria. Among several LAB species isolated from fermented cucumber spoilage, Lactobacillus buchneri was unique in its ability to metabolize lactic acid in FCS with concurrent increases in acetic acid and 1,2‐propanediol. Therefore, L. buchneri may be one of multiple organisms that contribute to development of fermented cucumber spoilage.}, number={7}, journal={JOURNAL OF FOOD SCIENCE}, author={Johanningsmeier, Suzanne D. and Franco, Wendy and Perez-Diaz, Ilenys and McFeeters, Roger F.}, year={2012}, month={Jul}, pages={M397–M404} }
 @article{franco_perez-diaz_2012, title={Role of selected oxidative yeasts and bacteria in cucumber secondary fermentation associated with spoilage of the fermented fruit}, volume={32}, ISSN={["1095-9998"]}, DOI={10.1016/j.fm.2012.07.013}, abstractNote={Changes during the spoilage of fermented cucumber pickles have been attributed to the metabolism of different yeasts and bacteria. In this study six organisms isolated from commercial spoiled cucumber pickles were evaluated for their possible role in primary and secondary cucumber fermentations. The ability of the yeasts Issatchenkia occidentalis and Pichia manshurica to utilize lactic and acetic acids during aerobic metabolism was confirmed and associated with increases in brine pH and the chemical reduction of the fermentation matrix. Lactobacillus buchneri and Pediococcus ethanolidurans were able to produce lactic acid from sugars, but only L. buchneri produced acetic acid at the expense of lactic acid under both aerobic and anaerobic conditions regardless of the initial acidic pH of 3.2 in the medium. The formation of secondary products was associated with the metabolism of Clostridium bifermentans and Enterobacter cloacae, which metabolic activity was observed at medium pH above 4.5. Individually, the selected spoilage microorganisms were found to be able to produce changes associated with secondary cucumber fermentations. The fact that oxidative yeasts and L. buchneri were able to produce chemical changes associated with the initiation of the spoilage process indicates that prevention of the secondary fermentation could be achieved by inhibiting these organisms.}, number={2}, journal={FOOD MICROBIOLOGY}, author={Franco, Wendy and Perez-Diaz, Ilenys M.}, year={2012}, month={Dec}, pages={338–344} }
 @article{lu_breidt_perez-diaz_osborne_2011, title={Antimicrobial Effects of Weak Acids on the Survival of Escherichia coli O157:H7 under Anaerobic Conditions}, volume={74}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028x.jfp-10-404}, abstractNote={Outbreaks of disease due to vegetative bacterial pathogens associated with acid foods (such as apple cider) have raised concerns about acidified vegetables and related products that have a similar pH (3.2 to 4.0). Escherichia coli O157:H7 and related strains of enterohemorrhagic E. coli (EHEC) have been identified as the most acid resistant vegetative pathogens in these products. Previous research has shown that the lack of dissolved oxygen in many hermetically sealed acid or acidified food products can enhance survival of EHEC compared with their survival under aerobic conditions. We compared the antimicrobial effects of several food acids (acetic, malic, lactic, fumaric, benzoic, and sorbic acids and sulfite) on a cocktail of EHEC strains under conditions representative of non-heat-processed acidified vegetables in hermetically sealed jars, holding the pH (3.2) and ionic strength (0.342) constant under anaerobic conditions. The overall antimicrobial effectiveness of weak acids used in this study was ranked, from most effective to least effective: sulfite > benzoic acid > sorbic acid > fumaric acid > L- and D-lactic acid > acetic acid > malic acid. These rankings were based on the estimated protonated concentrations required to achieve a 5-log reduction in EHEC after 24 h of incubation at 30°C. This study provides information that can be used to formulate safer acid and acidified food products and provides insights about the mode of action of weak acids against EHEC.}, number={6}, journal={JOURNAL OF FOOD PROTECTION}, author={Lu, Huiying J. and Breidt, Frederick, Jr. and Perez-Diaz, Ilenys M. and Osborne, Jason A.}, year={2011}, month={Jun}, pages={893–898} }
 @article{perez-diaz_mcfeeters_2011, title={Preparation of a Lactobacillus Plantarum Starter Culture for Cucumber Fermentations That Can Meet Kosher Guidelines}, volume={76}, ISSN={["0022-1147"]}, DOI={10.1111/j.1750-3841.2010.01981.x}, abstractNote={Abstract:  A method is described for growth of a Lactobacillus plantarum starter culture in jars of commercially available pasteurized fresh‐pack kosher dill cucumbers so that jars can be used to inoculate commercial scale cucumber fermentation tanks. A procedure is also described to transfer lactic acid bacteria from frozen storage in MRS broth into cucumber juice and commercial jars of kosher dill cucumbers so that a selected strain of lactic acid bacteria can be kosher certified for commercial fermentations in processing plants that operate under kosher certification. The strain of L. plantarum used in these experiments grew to maximum cell numbers in 4 d at 20 to 25 °C and then maintained viable cell numbers for 2 wk at >108 CFU/mL so the culture was suitable for inoculation of fermentation tanks. Refrigeration of jars of culture after they grow to maximum numbers minimizes die‐off of cells sufficiently so that a pure culture can be maintained by aseptically transferring brine containing viable bacteria to a new pH‐adjusted jar only once every 4 mo.}, number={2}, journal={JOURNAL OF FOOD SCIENCE}, author={Perez-Diaz, I. M. and McFeeters, R. F.}, year={2011}, month={Mar}, pages={M120–M123} }
 @article{perez-diaz_2011, title={Preservation of Acidified Cucumbers with a Combination of Fumaric Acid and Cinnamaldehyde That Target Lactic Acid Bacteria and Yeasts}, volume={76}, ISSN={["1750-3841"]}, DOI={10.1111/j.1750-3841.2011.02299.x}, abstractNote={Abstract:  The naturally occurring compound, fumaric acid, was evaluated as a potential preservative for the long‐term storage of cucumbers. Fumaric acid inhibited growth of lactic acid bacteria (LAB) in an acidified cucumber juice medium model system resembling conditions that could allow preservation of cucumbers in the presence of sodium benzoate. Forty millimolars of fumaric acid were required to inhibit growth of an extremely aciduric Lactobacillus plantarum LA0445 strain at pH 3.8. Half of this concentration was required to achieve inhibition of L. plantarum LA0445 at pH 3.5. As expected growth of the spoilage yeasts Zygosaccharomyces globiformis and Z. bailii was not inhibited by fumaric acid at near saturation concentrations in the same cucumber juice medium. To usefully apply fumaric acid as a preservative in acidified foods it will be necessary to combine it with a food grade yeast inhibitor. The antimicrobial agent, cinnamaldehyde (3.8 mM) prevented growth of Z. globiformis as well as the yeasts that were present on fresh cucumbers. Acidified cucumbers were successfully preserved, as indicated by lack of yeasts or LAB growth and microbial lactic acid or ethanol production by a combination of fumaric acid and cinnamaldehyde during storage at 30 °C for 2 mo. This combination of 2 naturally occurring preservative compounds may serve as an alternative approach to the use of sodium benzoate, potassium sorbate, or sodium metabisulfite for preservation of acidified vegetables without a thermal process.}, number={7}, journal={JOURNAL OF FOOD SCIENCE}, author={Perez-Diaz, Ilenys M.}, year={2011}, month={Sep}, pages={M473–M477} }
 @article{mcfeeters_perez-diaz_2010, title={Fermentation of Cucumbers Brined with Calcium Chloride Instead of Sodium Chloride}, volume={75}, ISSN={["0022-1147"]}, DOI={10.1111/j.1750-3841.2010.01558.x}, abstractNote={ABSTRACT:  Waste water containing high levels of NaCl from cucumber fermentation tank yards is a continuing problem for the pickled vegetable industry. A major reduction in waste salt could be achieved if NaCl were eliminated from the cucumber fermentation process. The objectives of this project were to ferment cucumbers in brine containing CaCl2 as the only salt, to determine the course of fermentation metabolism in the absence of NaCl, and to compare firmness retention of cucumbers fermented in CaCl2 brine during subsequent storage compared to cucumbers fermented in brines containing both NaCl and CaCl2 at concentrations typically used in commercial fermentations. The major metabolite changes during fermentation without NaCl were conversion of sugars in the fresh cucumbers primarily to lactic acid which caused pH to decrease to less than 3.5. This is the same pattern that occurs when cucumbers are fermented with NaCl as the major brining salt. Lactic acid concentration and pH were stable during storage and there was no detectable production of propionic acid or butyric acid that would indicate growth of spoilage bacteria. Firmness retention in cucumbers fermented with 100 to 300 mM CaCl2 during storage at a high temperature (45 °C) was not significantly different from that obtained in fermented cucumbers with 1.03 M NaCl and 40 mM CaCl2. In closed jars, cucumber fermentations with and without NaCl in the fermentation brine were similar both in the chemical changes caused by the fermentative microorganisms and in the retention of firmness in the fermented cucumbers.}, number={3}, journal={JOURNAL OF FOOD SCIENCE}, author={McFeeters, Roger F. and Perez-Diaz, Ilenys}, year={2010}, month={Apr}, pages={C291–C296} }
 @article{perez-diaz_mcfeeters_2010, title={Preservation of Acidified Cucumbers with a Natural Preservative Combination of Fumaric Acid and Allyl Isothiocyanate that Target Lactic Acid Bacteria and Yeasts}, volume={75}, ISSN={["0022-1147"]}, DOI={10.1111/j.1750-3841.2010.01587.x}, abstractNote={ABSTRACT:  Without the addition of preservative compounds cucumbers acidified with 150 mM acetic acid with pH adjusted to 3.5 typically undergo fermentation by lactic acid bacteria. Fumaric acid (20 mM) inhibited growth of Lactobacillus plantarum and the lactic acid bacteria present on fresh cucumbers, but spoilage then occurred due to growth of fermentative yeasts, which produced ethanol in the cucumbers. Allyl isothiocyanate (2 mM) prevented growth of Zygosaccharomyces globiformis, which has been responsible for commercial pickle spoilage, as well as the yeasts that were present on fresh cucumbers. However, allyl isothiocyanate did not prevent growth of Lactobacillus plantarum. When these compounds were added in combination to acidified cucumbers, the cucumbers were successfully preserved as indicated by the fact that neither yeasts or lactic acid bacteria increased in numbers nor were lactic acid or ethanol produced by microorganisms when cucumbers were stored at 30 °C for at least 2 mo. This combination of 2 naturally occurring preservative compounds may serve as an alternative approach to the use of sodium benzoate or sodium metabisulfite for preservation of acidified vegetables without a thermal process.}, number={4}, journal={JOURNAL OF FOOD SCIENCE}, author={Perez-Diaz, I. M. and McFeeters, R. F.}, year={2010}, month={May}, pages={M204–M208} }
 @article{olsen_perez-diaz_2009, title={Influence of Microbial Growth on the Redox Potential of Fermented Cucumbers}, volume={74}, ISSN={["1750-3841"]}, DOI={10.1111/j.1750-3841.2009.01121.x}, abstractNote={ABSTRACT:  Commonly, pH measurements are used during the production of fermented cucumbers to indirectly monitor growth of lactic acid bacteria (LAB) and acid production. Redox potential (Eh) measurements, which are determined by the potential of an electron to reduce an acceptor, could serve as an alternative tool to monitor the progress of fermentation allowing the detection of the metabolic activity and/or growth of LAB and other microorganisms. Pasteurized and inoculated jars of cucumbers were observed to better understand how the Eh changes during the cucumber fermentation and how it could be used as a monitoring tool. Jars of diced, brined cucumbers were pasteurized and inoculated with microbes previously isolated from fermented cucumbers including Lactobacillus plantarum, Zygosaccharomyces globiformis, and Enterobacter aerogenes. Although an initial decrease in Eh was observed for all microorganisms, distinctive trends in Eh occurred when these organisms were inoculated. After a 2‐wk fermentation period, the Eh (Ag/AgCl, 3 M KCl) in jars inoculated with L. plantarum, Z. globiformis, and E. aerogenes was at +453 ± 55, +104 ± 5, and –156 ± 73 mV, respectively. Cucumbers inoculated with a mixture of L. plantarum and Z. globiformis had a terminal Eh value of +202 ± 24 mV, which was between that found for the individual microorganisms. L. plantarum dominated the Eh trend when inoculated along with E. aerogenes with a final Eh of +411 ± 72 mV. The results showed that changes in Eh continued after pH measurements became stable. Thus Eh measurement can provide a tool to continuously monitor microbial growth during the course of cucumber fermentations.}, number={4}, journal={JOURNAL OF FOOD SCIENCE}, author={Olsen, Maegan J. and Perez-Diaz, Ilenys M.}, year={2009}, month={May}, pages={M149–M153} }
 @article{perez-diaz_mcfeeters_2009, title={Modification of azo dyes by lactic acid bacteria}, volume={107}, ISSN={["1364-5072"]}, DOI={10.1111/j.1365-2672.2009.04227.x}, abstractNote={Aim:  The ability of Lactobacillus casei and Lactobacillus paracasei to modify the azo dye, tartrazine, was recently documented as the result of the investigation on red coloured spoilage in acidified cucumbers. Fourteen other lactic acid bacteria (LAB) were screened for their capability to modify the food colouring tartrazine and other azo dyes of relevance for the textile industry.}, number={2}, journal={JOURNAL OF APPLIED MICROBIOLOGY}, author={Perez-Diaz, I. M. and McFeeters, R. F.}, year={2009}, month={Aug}, pages={584–589} }
 @article{perez-diaz_truong_webber_mcfeeters_2008, title={Microbial growth and the effects of mild acidification and preservatives in refrigerated sweet potato puree}, volume={71}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028X-71.3.639}, abstractNote={Refrigerated sweet potato puree is a convenient form of sweet potato that can be used as an ingredient in formulated foods. The microbiology of refrigerated sweet potato puree during storage for up to 5 weeks was evaluated. Because the puree was made by comminuting steam-cooked sweet potatoes before refrigeration, no naturally occurring vegetative bacterial cells were detected during a 4-week period of refrigerated storage at 4 degrees C. However, if postprocessing microbial contamination of the puree were to occur, contaminating microorganisms such as Listeria monocytogenes could grow during refrigerated storage. The effects of acidification or the addition of potassium sorbate and sodium benzoate on a population of L. monocytogenes inoculated into refrigerated (4 degrees C) sweet potato puree were determined. Inoculation of the refrigerated puree with L. monocytogenes at 10(6) CFU/ml resulted in a 3-log increase after 3 weeks storage of nonsupplemented puree. Supplementation of the sweet potato puree with 0.06% (wt/vol) sorbic acid or benzoic acid plus mild acidification of the sweet potato puree with citric acid to pH 4.2 prevented growth of L. monocytogenes during storage at 4 degrees C.}, number={3}, journal={JOURNAL OF FOOD PROTECTION}, author={Perez-Diaz, Ilenys M. and Truong, Van-Den and Webber, Ashlee and Mcfeeters, Roger F.}, year={2008}, month={Mar}, pages={639–642} }
 @article{perez-diaz_mcfeeters_2008, title={Microbiological preservation of cucumbers for bulk storage using acetic acid and food preservatives}, volume={73}, ISSN={["1750-3841"]}, DOI={10.1111/j.1750-3841.2008.00795.x}, abstractNote={ABSTRACT:  Microbial growth did not occur when cucumbers were preserved without a thermal process by storage in solutions containing acetic acid, sodium benzoate, and calcium chloride to maintain tissue firmness. The concentrations of acetic acid and sodium benzoate required to ensure preservation were low enough so that stored cucumbers could be converted to the finished product without the need to wash out and discard excess acid or preservative. Since no thermal process was required, this method of preservation would be applicable for storing cucumbers in bulk containers. Acid tolerant pathogens died off in less than 24 h with the pH, acetic acid, and sodium benzoate concentrations required to assure the microbial stability of cucumbers stored at 30 °C. Potassium sorbate as a preservative in this application was not effective. Yeast growth was observed when sulfite was used as a preservative.}, number={6}, journal={JOURNAL OF FOOD SCIENCE}, author={Perez-Diaz, I. M. and McFeeters, R. F.}, year={2008}, month={Aug}, pages={M287–M291} }
 @article{perez-diaz_kelling_hale_breidt_mcfeeters_2007, title={Lactobacilli and tartrazine as causative a agents of red-color spoilage in cucumber pickle products}, volume={72}, ISSN={["0022-1147"]}, DOI={10.1111/j.1750-3841.2007.00460.x}, abstractNote={ABSTRACT:  The cucumber pickling industry has sporadically experienced spoilage outbreaks in pickled cucumber products characterized by development of red color on the surface of the fruits. Lactobacillus casei and Lactobacillus paracasei were isolated from 2 outbreaks of this spoilage that occurred about 15 y apart during the last 3 decades. Both organisms were shown to produce this spoilage when inoculated into pickled cucumbers while concomitantly degrading the azo dye tartrazine (FD&C yellow nr 5). This food dye is used as a yellow coloring in the brine cover solutions of commercial pickled cucumber products. The red color does not occur in the absence of tartrazine, nor when turmeric is used as a yellow coloring in the pickles. Addition of sodium benzoate to the brine cover solutions of a pickled cucumber product, more specifically hamburger dill pickles, prevented growth of these lactic acid bacteria and the development of the red spoilage.}, number={7}, journal={JOURNAL OF FOOD SCIENCE}, author={Perez-Diaz, I. M. and Kelling, R. E. and Hale, S. and Breidt, F. and McFeeters, R. F.}, year={2007}, month={Sep}, pages={M240–M245} }