title: Growth and survival of Salmonella in ground black pepper (Piper nigrum).
abstract: A four serovar cocktail of Salmonella was inoculated into ground black pepper (Piper nigrum) at different water activity (aw) levels at a starting level of 4-5 log cfu/g and incubated at 25 and at 35 °C. At 35 °C and aw 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 aw 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, aw 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 aw in ground black pepper and may persist for an extended period of time under typical storage conditions.
authors.affiliation: U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, 6502 South Archer Road, Bedford Park, IL 60501, USA. Susanne.Keller@fda.hhs.gov
authors.forename: Susanne E
authors.initials: SE
authors.lastname: Keller
authors.forename: Jane M
authors.initials: JM
authors.lastname: VanDoren
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Grasso
authors.forename: Lindsay A
authors.initials: LA
authors.lastname: Halik
mesh_terms: D015169:Colony Count, Microbial; D005506:Food Contamination; D061353:Food Storage; D006813:Humidity; D050296:Microbial Viability; D029222:Piper nigrum / Q000382:microbiology*; D012475:Salmonella / Q000254:growth & development*; D013696:Temperature