Effective chemical control of psychrotrophic Bacillus cereus EPSO-35AS and INRA TZ415 spore outgrowth in carrot broth.
The growth kinetic parameters of germinated cells from heat-activated spores of the psychrotrophic Bacillus cereus EPSO-35AS strain in nutrient broth (NB) and in tyndallized carrot broth (TCB) were evaluated at different temperatures (8, 12, and 16 degrees C) for control samples and for samples acidified with citric acid or lemon juice at pH values between 4.7 and 5.5. Lowering the pH from 7.4 or 6.2 to 5.2 inhibited bacterial growth in both tested media after 60 days at 12 degrees C and lower temperatures, confirming the effectiveness of acidification in association with refrigeration to control B. cereus proliferation in minimally processed foods (MPFs) based on carrot. The activities of selected concentrations of cinnamon essential oil, cinnamaldehyde, carvacrol, and eugenol against B. cereus EPSO-35AS and INRA TZ415 strains in both media over the same temperature range were also studied. Addition of either cinnamon essential oil or cinnamaldehyde at concentrations of 5 and 2 microL 100mL(-1), respectively, caused complete inhibition of the growth of both psychrotrophic strains even if mild temperature abuse occurred (12 degrees C). Hence, a combination of one of these compounds and refrigerated storage may be useful for preservation of MPFs in which major ingredient was carrot. On the contrary, carvacrol and eugenol were not able to prevent B. cereus growth in TCB during storage at 8 degrees C. Their effects on the organoleptic characteristics of TCB are discussed.
Departamento de Producción Vegetal y Microbiología, Escuela Politécnica Superior de Orihuela, Universidad Miguel Hernández-Campus de Orihuela, Carretera de Beniel km 3.2, 03312 Orihuela, Alicante, Spain.
L A
LA
Hernández-Herrero
M J
MJ
Giner
M
M
Valero
D000171:Acrolein / Q000031:analogs & derivatives; D001409:Bacillus cereus / Q000187:drug effects* / Q000502:physiology; D003257:Consumer Product Safety; D018552:Daucus carota / Q000382:microbiology*; D004357:Drug Synergism; D005511:Food Handling / Q000379:methods*; D005519:Food Preservation / Q000379:methods*; D018525:Germination; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009822:Oils, Volatile / Q000494:pharmacology; D012034:Refrigeration; D013171:Spores, Bacterial / Q000254:growth & development*; D013696:Temperature; D013997:Time Factors
D009822:Oils, Volatile; D000171:Acrolein; C012843:cinnamaldehyde