Effect of antioxidants and competing mycoflora on Fusarium verticillioides and F. proliferatum populations and fumonisin production on maize grain

This study was carried out to determine the temporal effect of the antioxidants butylated hydroxyanisol (BHA) and propyl paraben (PP) at doses of 500 and 1000 μg/g on the growth of Fusarium verticillioides and F. proliferatum inoculated on natural maize grain in the presence of the competing mycoflora and fumonisin production at 0.98 and 0.95 water activity (a_w) over a 28-day storage period. The reduction in the log colony forming units (CFU) of Penicillium, Aspergillus and Fusarium populations was 10-100 fold depending on dose of BHA or PP, a_w and time. However, the populations of all three groups were higher at 0.98 a_w than 0.95 a_w. BHA at 500 μg/g and 0.95 a_w reduced the fumonisin content by 82% after 7-14 days incubation, but at the end of the experimental period the reduction was only 32%. A higher reduction in the level of fumonisin produced (77%) was achieved with BHA at 1000 μg/g after 28 days. PP at 500 and 1000 μg/g decreased fumonisin production throughout the incubation period in the drier treatment, but at 0.98 a_w control of toxin production was only achieved after 7-14 days. The reduction in the fumonisin levels could be due to the combined effect of antioxidants, and the competing mycoflora, mainly Aspergillus and Penicillium species.     

Distribution of zearalenone in malted barley fractions dependent on Fusarium graminearum growing conditions

Zearalenone (ZON) distribution was measured in main fractions of malted barley, dependent on incubation time (17, 26, 34 days), water activity (0.95 and 0.98) and temperature (20 °C and 30 °C). Malted samples were sterilised and inoculated with Fusarium graminearum. ZON levels were higher (p < 0.01) in bran and germ than flour under almost all growing conditions. Incubation at 30 °C resulted in generally lower ZON levels in germ and bran, regardless of a_w and incubation time. After 34 days, ZON levels in flour from samples that were incubated at the higher temperature rose significantly. At 20 °C ZON concentration showed a bell-shaped concentration profile with increasing incubation time in bran and germ, whilst ZON levels in flour increased at a_w 0.98 and dropped at the lower a_w. The results indicate the importance of storage conditions for ZON levels in commercially relevant grain fractions of malted barley and help predict existing mycotoxin levels or manipulate storage conditions to reduce ZON content.     

Water activity and temperature effects on mycotoxin production by Alternaria alternata on a synthetic tomato medium

Alternaria spp. have been reported to be the most frequent fungal species invading tomatoes. Certain species, in particular the most common one, A. alternata, are capable of producing several mycotoxins in infected plants and in agricultural commodities. Alternariol (AOH), alternariol monomethyl ether (AME), and tenuazonic acid (TA) are some of the main Alternaria mycotoxins that can be found as contaminants of food. The objective of this study was to determine the effect of water activity (a_w, 0.904, 0.922, 0.954, and 0.982) and temperature (6, 15, 21 and 35 °C) on mycotoxin production on a synthetic tomato medium of a cocktail inoculum of five strains of A. alternata isolated from tomato fruits affected by Blackmould. The optimum AOH production occurred at 0.954 a_w after 28 days of incubation at 21 °C. A temperature of 21 °C was the most favourable for AOH synthesis at all a_w levels. The maximum concentration of AME was determined at 0.954 a_w and 35 °C. The optimum conditions for TA accumulation were 0.982 a_w and 21 °C. At the 0.904 a_w no growth or germination was registered at 6 °C and 15 °C over the whole incubation period. At 21 °C and 35 °C growth occurred slowly but none of the toxins were detected at this a_w level. In general, high a_w levels were favourable for mycotoxin production. None of the other toxins was detected at quantifiable levels at 6 °C after the whole incubation period. A storage temperature of 6 °C or below could be considered as safe for tomato fruits and high moisture tomato products (a_w > 0.95), in relation with Alternaria toxins. The results obtained here could be extrapolated to evaluate the risk of spoilage in tomato fruits and tomato products caused by this pathogen.     

A new cytotoxic cyclic pentadepsipeptide,neo-N-methylsansalvamide produced by Fusarium solani KCCM90040, isolated from potato

A new cytotoxic cyclic pentadepsipeptide, neo-N-methylsansalvamide, was produced by Fusarium solani KCCM90040, which was isolated from potato in Korea. The species of Fusarium was identified as F. solani by examining its morphological characteristics and by ITS-5.8rDNA sequence analysis. This compound was analysed for C₃₃H₅₂N₄O₆ by electrospray ionisation mass spectrometry and combined structural analysis. The one and two-dimensional NMR and the absolute configurations of amino acids spectral data allowed the resolution of five subunits linked in the following order: (S)-2-hydroxy-4-methylpentanoic acid, N-methyl-l-leucine, l-valine, l-leucine, and l-phenylalanine. The in vitro cytotoxic effect of the purified cyclic pentadepsipeptide was evaluated to establish the possibility that it would be a biohazard if present in foods. The concentrations of purified cyclic pentadepsipeptide required to inhibit cell growth in vitro by 50% for A549 (lung cancer), SK-OV-3 (ovarian cancer), SK-MEL-2 (skin melanoma), and MES-SA (uterine sarcoma) cell lines were 10.7 ± 0.15, 11.2 ± 1.23, 10.0 ± 0.53, and 14.0 ± 0.74 M, respectively (mean ± SE).     

Molecular characterization and fumonisin production by Fusarium verticillioides isolated from corn grains of different geographic origins in Brazil

Gibberella moniliformis is most commonly associated with maize worldwide and produces high levels of fumonisins, some of the most agriculturally important mycotoxins. Studies demonstrate that molecular methods can be helpful for a rapid identification of Fusarium species and their levels of toxin production. The purpose of this research was to apply molecular methods (AFLP, TEF-1α partial gene sequencing and PCR based on MAT alleles) for the identification of Fusarium species isolated from Brazilian corn and to verify if real time RT-PCR technique based on FUM1 and FUM19 genes is appropriated to estimate fumonisins B₁ and B₂ production levels. Among the isolated strains, 96 were identified as Fusarium verticillioides, and four as other Fusarium species. Concordant phylogenies were obtained by AFLP and TEF-1α sequencing, permitting the classification of the different species into distinct clades. Concerning MAT alleles, 70% of the F. verticillioides isolates carried the MAT-1 and 30% MAT-2. A significant correlation was observed between the expression of the genes and toxin production r = 0.95 and r = 0.79 (correlation of FUM1 with FB₁ and FB₂, respectively, P < 0.0001); r = 0.93 and r = 0.78 (correlation of FUM19 with FB₁ and FB₂, respectively, P < 0.0001). Molecular methods used in this study were found to be useful for the rapid identification of Fusarium species. The high and significant correlation between FUM1 and FUM19 expression and fumonisins production suggests that real time RT-PCR is suitable for studies considering the influence of abiotic and biotic factors on expression of these genes. This is the first report concerning the expression of fumonisin biosynthetic genes in Fusarium strains isolated from Brazilian agricultural commodity.     

Effect of fenpropimorph, prochloraz and tebuconazole on growth and production of T-2 and HT-2 toxins by Fusarium langsethiae in oat-based medium

Fusarium langsethiae has been isolated from infected cereals in central and northern Europe where it has been identified in the last decade as the main species involved in the occurrence of high levels of T-2 and HT-2 toxins, mainly in oats. The efficacy of three fungicides (prochloraz, tebuconazole, fenpropimorph) for controlling growth of two strains of F. langsethiae isolated from oats was examined at 0.96 and 0.98 a_w at 15, 20 and 25 °C on oat-based media. The concentrations necessary for 50 and 90% growth inhibition (ED₅₀ and ED₉₀ values) were determined. The effect on the trichothecene type A mycotoxins T-2 and HT-2 was also determined. Without fungicides both strains grew faster at 0.98 than at 0.96 a_w and the influence of temperature on growth rates was 25 > 20 > 15 °C. Prochloraz and tebuconazole were more effective than fenpropimorph against F. langsethiae. Strain, temperature and type of fungicide significantly influenced the ED₅₀ and ED₉₀ values for growth. The concentration ranges under different environmental conditions were: prochloraz (0.03-0.1 and 0.3-1.5), tebuconazole (0.06-0.9 and 1.3-8.2), and fenpropimorph (22-59 and 125-215 mg l⁻¹). Production of T-2 and HT-2 toxins was influenced by temperature, a_w, type of fungicide and dose. Levels of T-2 were usually higher than those of HT-2 under the same conditions. The biosynthesis of T-2 toxin increased after 10 day incubation, but was reduced with decreasing temperature and increasing fungicide dose. At 0.98 a_w T-2 levels increased in cultures containing fenpropimorph while at 0.96 a_w the toxin concentrations increased in response to the other two fungicides. Low doses of prochloraz or tebuconazole enhanced toxin production when compared with untreated cultures for strain 2004-59 at 0.96 a_w and 20-25 °C. HT-2 was hardly detectable in the treatments with prochloraz or tebuconazole at 0.98 a_w. This is the first study on the effect of these anti-fungal compounds on control of growth of F. langsethiae and on production of T-2 and HT-2 toxins in oat-based media.     

Effect of water activity, temperature and incubation time on growth and ochratoxin A production by Aspergillus niger and Aspergillus carbonarius on maize kernels

The aim of this study was to determine the effects of water activity (a_w) (0.92-0.98), temperature (5-45 °C) and incubation time (5-60 days) on growth and ochratoxin A (OTA) production by Aspergillus niger and Aspergillus carbonarius on maize kernels using a simple method. Colony diameters of both strains at 0.92 a_w were significantly lower than those at 0.96 and 0.98 a_w levels. The optimum growth temperature range for A. niger was 25-40 °C and for A. carbonarius 20-35 °C. A. niger produced OTA from 15 to 40 °C, and the highest OTA level was recorded at 15 °C. The concentration of OTA produced at 0.92 a_w was significantly lower than those at 0.96 and 0.98 a_w. A. carbonarius produced OTA from 15 to 35 °C and the maximum concentration was achieved at 15 °C, although not differing statistically from the concentration detected at 20 °C. At 0.98 a_w the OTA concentration was significantly higher than at 0.96 and 0.92 a_w. Our results show that maize supports both growth and OTA production by A. niger and A. carbonarius. The studied strains were able to produce OTA in maize kernels from the fifth day of incubation over a wide range of temperatures and water availabilities. Although the limit of quantification of our method was higher than that required for the analysis of OTA in food commodities, it has proved to be a useful and rapid way to detect OTA production by fungi inoculated onto natural substrates, in a similar way as for pure culture. Both species could be a source of OTA in this cereal in temperate and tropical zones of the world.     

Antioxidant activities of Sideritis congesta Davis et Huber-Morath and Sideritis arguta Boiss et Heldr: Identification of free flavonoids and cinnamic acid derivatives

Different solvent extracts of endemic Sideritis (Labiatae) species, Sideritis congesta Davis et Huber-Morath and Sideritis arguta Boiss et Heldr, were analyzed for free flavonoids (quercetin, apigenin, myricetin and kaempferol) and cinnamic acid derivatives (rosmarinic acid, ferulic acid, caffeic acid, p-coumaric acid and chlorogenic acid) using HPLC-DAD. All the phenolics were quantified in acid-hydrolyzed extracts, except rosmarinic acid, chlorogenic acid and myricetin which were quantified in raw samples. Antioxidant activities of extracts of these two plants and many of their components in pure form were evaluated based on DPPH^. and ABTS^.+ assays. In general, S. arguta extracts displayed higher antioxidant activity than S. congesta extracts possibly due to their richness in antioxidant components of strong activity. Acetone extract of S. arguta, with its strikingly high TEAC value of 3.2 mM trolox and low IC₅₀ value of 38.3 ??g/mL showed the highest antioxidant potency among all extracts. ??-tocopherol, the positive control, displayed IC₅₀ and TEAC values of 33.8 ??g/mL and 2.9 mM trolox, respectively. No direct correlation was found between antioxidant activities and total phenolic contents of the plant extracts studied.     

Biochemical characterization and process stability of polyphenoloxidase extracted from Victoria grape (Vitis vinifera ssp. Sativa)

Polyphenol oxidase (PPO) was isolated from Victoria grapes (Vitis vinifera ssp. Sativa) grown in South Africa and its biochemical characteristics were studied. Optimum pH and temperature for grape PPO activity were pH 5.0 and T = 25 °C with 10 mM catechol in McIlvaine buffer as substrate. PPO showed activity using the following substances: catechol, 4 methyl catechol, d, l-DOPA, (+) catechin and chlorogenic acid. K_m and V_max values were 52.6 ± 0.00436 mM and 653 ± 24.0 OD_400 nm/min in the case of 10 mM catechol as a substrate. Eight inhibitors were tested in this study and the most effective inhibitors were found to be ascorbic acid, l-cysteine and sodium metabisulfite. Kinetic studies showed that the thermal inactivation of Victoria grape PPO followed first-order kinetics, with an activation energy, E_a = 225 ± 13.5 of kJ/mol. Both in semipurified extract and in grape juice, PPO showed a pronounced high pressure stability.     

Influence of water activity and temperature on growth and mycotoxin production by Alternaria alternata on irradiated soya beans

The aim of this study was to determine the effects of water activity (a_w) (0.99-0.90), temperature (15, 25 and 30 °C) and their interactions on growth and alternariol (AOH) and alternariol monomethyl ether (AME) production by Alternaria alternata on irradiated soya beans. Maximum growth rates were obtained at 0.980 a_w and 25 °C. Minimum a_w level for growth was dependent on temperature. Both strains were able to grow at the lowest a_w assayed (0.90). Maximum amount of AOH was produced at 0.98 a_w but at different temperatures, 15 and 25 °C, for the strains RC 21 and RC 39 respectively. Maximum AME production was obtained at 0.98 a_w and 30 °C for both strains. The concentration range of both toxins varied considerably depending on a_w and temperature interactions. The two metabolites were produced over the temperature range 15 to 30 °C and a_w range 0.99 to 0.96. The limiting a_w for detectable mycotoxin production is slightly greater than that for growth. Two-dimensional profiles of a_w × temperature were developed from these data to identify areas where conditions indicate a significant risk from AOH and AME accumulation on soya bean. Knowledge of AOH and AME production under marginal or sub-optimal temperature and a_w conditions for growth can be important since improper storage conditions accompanied by elevated temperature and moisture content in the grain can favour further mycotoxin production and lead to reduction in grain quality. This could present a hazard if the grain is used for human consumption or animal feedstuff.     

Purification and characterization of a novel glucoamylase from Fusarium solani

Thermostable enzymes are currently being investigated to improve industrial processes of starch saccharification. A novel glucoamylase was purified to electrophoretic homogeneity from the culture supernatant of Fusarium solani on a fast protein liquid chromatographic system (FPLC). The recovery of glucoamylase after gel filtration on FPLC was 31.8% with 26.2-fold increase in specific activity. The enzyme had a molecular mass of 40 kDa by SDS-PAGE and 41 kDa by gel filtration. The glucoamylase exhibited optimum activity at pH 4.5. The K_cat and K_m were 441/min and 1.9 mg/ml, respectively, for soluble starch, specificity constant (K_cat/K_m) was 232. The enzyme was thermally stable at 50 °C and retained 79% activity after 60 min at this temperature. The half-life of the enzyme was 26 min at 60°C. The enzyme was slightly stimulated by Cu²⁺ and Mg²⁺ and strongly inhibited by Hg²⁺, Pb²⁺, Zn²⁺, Ni²⁺ and Fe³⁺.     

Profiling of in vitro neurobiological effects and phenolic acids of selected endemic Salvia species

The ethyl acetate and methanol extracts from 16 Salvia L. species were screened for their inhibitory activity against acetylcholinesterase, butyrylcholinesterase, lipoxygenase, and tyrosinase; the enzymes linked to neurodegeneration. Their antioxidant activity was also tested using DPPH radical scavenging, metal-chelation, and ferric-reducing antioxidant power (FRAP) assays. Total flavonoid content of the extracts was determined by AlCl₃ reagent, while HPLC technique was applied for analysis of various phenolic acids in the extracts. The extracts exerted weak cholinesterase and tyrosinase inhibition, and remarkable inhibition against lipoxygenase (13.07 ± 2.73-74.21 ± 5.61%) at 100 μg ml⁻¹. The methanol extracts showed higher antioxidant activity in DPPH radical scavenging and FRAP assays. The extracts were analyzed for their gallic, protocateuchic, p-hydroxy-benzoic, vanillic, caffeic, chlorogenic, syringic, o- and p-coumaric, ferulic, rosmarinic, and tr-cinnamic acid contents and the methanol extract of Salvia ekimiana (153.50 mg 100 g⁻¹) was revealed to be the richest in terms of rosmarinic acid.     

Modelling the effect of temperature and water activity on the growth rate and growth/no growth interface of Byssochlamys fulva and Byssochlamys nivea

The purpose of the present study was to apply a modelling approach to define the growth rate and growth/no growth interface of Byssochlamys fulva and Byssochlamys nivea on a synthetic medium as a function of temperature and water activity. Both fungal species were grown on malt extract agar at different temperatures (10, 15, 20, 25, 30, 35, 40 and 45 °C) and a_w levels (0.88, 0.90, 0.92, 0.94, 0.96 and 0.99) for a period of 30 days. Growth responses were evaluated over time in terms of colony diameter changes. Growth data were fitted to the primary model of Baranyi and the resulting growth rates were further modeled as a function of temperature and water activity using the cardinal model with inflection (CMI) ( Rosso et al., 1993). A logistic regression quadratic polynomial model was also employed to predict the probability of growth over storage time. Estimated parameters for minimum, maximum and optimum temperatures for growth were 9.1 °C, 46.4 °C and 32.1 °C for B. fulva and 10.5 °C, 43.2 °C and 32.1 °C for B. nivea. The respective values for a_w were 0.893, 0.993 and 0.985 for B. fulva and 0.892, 0.992 and 0.984 for B. nivea. No growth was observed at 0.88 a_w regardless of temperature for both species, whereas B. nivea ascospores could not grow at 10 and 45 °C irrespective of a_w. Regarding growth boundaries, the degree of agreement between predictions and observations was >98% concordant for both species. The erroneously predicted growth cases were 1.4–4.2% false positive and 2.1–3.5% false negative for B. nivea and B. fulva, respectively. The developed logistic model was validated with two literature data sets as well as with data from independent experiments carried out on fruit juices. Validation results showed that agreement with literature data for growth was 25 out of 36 (69.4%) cases, whereas validation on fruit juice data failed in only 6 cases (5 false positives and 1 false negative) out of 128 cases.     

Phytochemical composition and thermal stability of two commercial açai species, Euterpe oleracea and Euterpe precatoria

Açai fruit are native to the Amazon region of South America and two predominant species are commercially exported as fruit pulps for use in food and beverage applications. Detailed characterisation of the polyphenolic compounds present in the de-seeded fruits of Euterpe oleracea and Euterpe precatoria species were conducted by HPLC–ESI–MSⁿ analyses and their thermal stability and overall influence on antioxidant capacity were determined. Anthocyanins were the predominant polyphenolics in both E. oleracea (2247 ± 23 mg/kg) and E. precatoria (3,458 ± 16 mg/kg) species, and accounted for nearly 90% of the trolox equivalent antioxidant capacity in both E. oleracea (87.4 ± 4.4 μmol TE/g) and E. precatoria (114 ± 6.9 μmol TE/g) fruits. Various flavones, including homoorientin, orientin, taxifolin deoxyhexose and isovitexin; various flavanol derivatives, including (+)-catechin, (−)-epicatechin, procyanidin dimers and trimers, and phenolic acids, including protocatechuic, p-hydroxybenzoic, vanillic, syringic and ferulic acids, were also present in both species. Thermal stability of these compounds was evaluated, following a thermal holding cycle (80 °C for up to 60 min) in the presence and absence of oxygen. Both species experienced only minor changes (<5%) in non-anthocyanin polyphenolic contents during all thermal processes whereas 34 ± 2.3% of anthocyanins in E. oleracea and 10.3 ± 1.1% of anthocyanins in E. precatoria were lost under these conditions, regardless of the presence of oxygen. Proportional decreases (10–25%) in antioxidant capacity accompanied the anthocyanin changes. Results suggest that both açai species are characterised by similar polyphenolic profiles, comparable antioxidant capacities, yet only moderate phytochemical stability during heating.     

Effects of menthol stereoisomers on the growth,sporulation and fumonisin B1 production of Fusarium verticillioides

Menthol is a naturally occurring cyclic terpene alcohol of plant origin from the Lamiaceae family. It has three chiral centres, implying eight possible different stereoisomers, which in turn define four pairs of enantiomers. This is the first work that reports on the stereoselective antifungal and antitoxigenic activities of the menthol stereoisomers on Fusarium verticillioides, with the (−)-menthol and (+)-menthol enantiomers found to be the most active inhibitors of fungal growth and sporulation. The results obtained suggest the importance of the presence of these substituents in the equatorial positions of menthol stereoisomers in the antifungal activity. The stereoisomer (−)-menthol, followed by (+)-menthol, were the most active compounds in the inhibition of fumonisin B₁ (FB₁) biosynthesis. The different antitoxigenic activities of (−)-menthol and (+)-menthol revealed that the molecular requirements to affect the FB₁ production were dependent not only on the presence of the substituents in the equatorial positions, but also on their spatial arrangements.     

Characterisation of lipoxygenase from pea seeds (Pisum sativum var. Telephone L.)

Lipoxygenase (LOX) from pea seeds (Pisum sativum var. Telephone L.) was extracted and studied of biochemical properties. The molecular mass of purified lipoxygenase was 93 kDa. The effects of substrate specificity, pH, and sensibility to various inhibitors: caffeic acid, ferulic acid, benzoic acid, catechin, quercetin and kaempferol of LOX were investigated. Lipoxygenase showed the highest activity toward linoleic acid and the lowest toward oleic acid as substrates. Kinetic studies indicated that V_max of the LOX activity was 151.5 U/min and corresponding K_m value of 0.44 × 10⁻³ M. Optimum pH of lipoxygenase was reported at 5.5. Caffeic acid was the most effective inhibitor and kaempferol was the least effective.     

Biochemical characteristics of Trametes multicolor pyranose oxidase and Aspergillus niger glucose oxidase and implications for their functionality in wheat flour dough

Similar to glucose oxidase (GO), pyranose oxidase (P₂O) may well have desired functionalities in some food applications in general, particularly breadmaking. As its name implies, P₂O oxidises a variety of monosaccharides. P₂O purified from a culture of Trametes multicolor (P₂O-Tm) had high affinity towards d-glucose (K_M = 3.1 mM) and lower affinity to other monosaccharides. GO from Aspergillusniger (GO-An) had a K_M value of 225 mM towards glucose, which points to a significant difference in glucose affinity between the two enzymes. Furthermore, P₂O-Tm had higher affinity towards O₂ (K_M = 0.46 mM) than GO-An (K_M = 2.9 mM). Dehydroascorbic acid did not accept electrons in the reactions catalysed by P₂O-Tm and GO-An. For the same activity towards glucose in saturating conditions, the rate of ferulic acid oxidation in a model system and of thiol oxidation in a wheat flour extract were higher with P₂O-Tm, than with GO-An. The demonstrated differences in properties and functional features between P₂O-Tm and GO-An allow prediction of differences in functional behaviour of the enzymes, in food applications.     

Characterisation of esterolytic activity from two wild mushroom species, Amanita vaginata var. vaginata and Tricholoma terreum

Characterisation of esterase activities from the edible mushroom species, Amanita vaginata var. vaginata and Tricholoma terreum, were investigated. Native electrophoresis of the crude extracts prepared from both mushroom samples showed the presence of esterolytic activities. The extracts had the greatest activity in the presence of p-nitrophenyl butyrate (pNPB) as a substrate. pH and temperature optima were found to be 8.0 and 30 °C for both enzymes, respectively. V_max and K_m values were determined as 14.2 U/l and 71 μM for A. vaginata var. vaginata and 34.6 U/l and 9.6 μM for T. terreum, respectively. The pH-stability profile showed a stationary line between 3.0 and 10.0 for both enzymes. The esterolytic activities from the extracts were maintained between 10 and 40 °C for 4 h and started to decrease at 50 °C. The effects of EDTA, NaN₃, DTT and PMSF on the enzyme activity were also investigated.     

Growth and survival of Salmonella in ground black pepper (Piper nigrum)

A four serovar cocktail of Salmonella was inoculated into ground black pepper (Piper nigrum) at different water activity (a_w) levels at a starting level of 4–5 log cfu/g and incubated at 25 and at 35 °C. At 35 °C and a_w of 0.9886 ± 0.0006, the generation time in ground black pepper was 31 ± 3 min with a lag time of 4 ± 1 h. Growth at 25 °C had a longer lag, but generation time was not statistically different from growth at 35 °C. The a_w threshold for growth was determined to be 0.9793 ± 0.0027 at 35 °C. To determine survival during storage conditions, ground black pepper was inoculated at approximately 8 log cfu/g and stored at 25 and 35 °C at high (97% RH) and ambient (≤40% RH) humidity. At high relative humidity, a_w increased to approximately 0.8–0.9 after approximately 20 days at both temperatures and no Salmonella was detected after 100 and 45 days at 25 and 35 °C, respectively. Under ambient humidity, populations showed an initial decrease of 3–4 log cfu/g, then remained stable for over 8 months at 25 and 35 °C. Results of this study indicate Salmonella can readily grow at permissive a_w in ground black pepper and may persist for an extended period of time under typical storage conditions.