TY - JOUR
T1 - Hurdle Approach to Simulate Corn Wet Milling Inactivation of Undesirable Microorganisms
T2 - A Pilot Scale Microbial Challenge Study Using Salmonella Surrogate Enterococcus faecium
AU - Kealey, Erin
AU - Shick, Madeline
AU - Kim, Minho
AU - Chavez, Ruben
AU - Shetley, Gordon
AU - Stenger, David
AU - Perreau, Kirk A.
AU - Cooke, Allison
AU - Barnett-Neefs, Cecil
AU - Stasiewicz, Matthew J.
N1 - Publisher Copyright:
© 2024 The Author(s)
PY - 2025/1/2
Y1 - 2025/1/2
N2 - Corn wet milling (CWM) and corn starch flash drying processing conditions reduce undesirable microorganisms, such as Salmonella. Finished products are historically safe, with intrinsic properties such as low water activity inhibiting microbial growth. Corn processors could use quantified levels of reduction in this study of Salmonella surrogate Enterococcus faecium (E. faecium) to update their food safety plans. Industry-relevant conditions for CWM processes were recreated at pilot or lab scale for 3 unit operations: (1) steeping treatment in sulfur dioxide (SO2) with low (750 ppm SO2, 20 h, 43.3 °C), medium (1,500 ppm SO2, 30 h, 48.9 °C), and high (2,200 ppm SO2, 40 h, 53.3 °C) treatment conditions; (2) hydrogen peroxide (H2O2) treatment tested on bench scale with a factorial design (pH 3.5, 4.0, and 4.5), H2O2 concentrations (0.05%, 0.10%, 0.15% (w/w)), and temperatures (32, 38, and 46 °C) for 3 and 6 h; (3) flash drying treatment at 4 different temperatures (149, 177, 204, and 232 °C) with 2 different inoculation methods. E. faecium was reduced during each of these unit operations. By the end of each steeping treatment, E. faecium was consistently below the limit of quantitation (LOQ), meaning >6.5 log CFU/mL reduction in steep water, and >3.7 log CFU/g reduction in ground corn. The peroxide step had a reduction range from 0.03 log CFU/mL in the control group (0% H2O2 added) to >6 log CFU/mL observed in the high-intensity treatment of corn starch slurry. Flash drying had a reduction range from 1.7 to 2.7 log CFU/g. There was also no biologically meaningful change (<1 log CFU/g reduction) of E. faecium counts during an 8-week survival study of the dried final product. This hurdle approach study shows that existing CWM conditions are effective for Salmonella surrogate reduction through processing into finished starch and provides quantified E. faecium reductions for use in food safety plans.
AB - Corn wet milling (CWM) and corn starch flash drying processing conditions reduce undesirable microorganisms, such as Salmonella. Finished products are historically safe, with intrinsic properties such as low water activity inhibiting microbial growth. Corn processors could use quantified levels of reduction in this study of Salmonella surrogate Enterococcus faecium (E. faecium) to update their food safety plans. Industry-relevant conditions for CWM processes were recreated at pilot or lab scale for 3 unit operations: (1) steeping treatment in sulfur dioxide (SO2) with low (750 ppm SO2, 20 h, 43.3 °C), medium (1,500 ppm SO2, 30 h, 48.9 °C), and high (2,200 ppm SO2, 40 h, 53.3 °C) treatment conditions; (2) hydrogen peroxide (H2O2) treatment tested on bench scale with a factorial design (pH 3.5, 4.0, and 4.5), H2O2 concentrations (0.05%, 0.10%, 0.15% (w/w)), and temperatures (32, 38, and 46 °C) for 3 and 6 h; (3) flash drying treatment at 4 different temperatures (149, 177, 204, and 232 °C) with 2 different inoculation methods. E. faecium was reduced during each of these unit operations. By the end of each steeping treatment, E. faecium was consistently below the limit of quantitation (LOQ), meaning >6.5 log CFU/mL reduction in steep water, and >3.7 log CFU/g reduction in ground corn. The peroxide step had a reduction range from 0.03 log CFU/mL in the control group (0% H2O2 added) to >6 log CFU/mL observed in the high-intensity treatment of corn starch slurry. Flash drying had a reduction range from 1.7 to 2.7 log CFU/g. There was also no biologically meaningful change (<1 log CFU/g reduction) of E. faecium counts during an 8-week survival study of the dried final product. This hurdle approach study shows that existing CWM conditions are effective for Salmonella surrogate reduction through processing into finished starch and provides quantified E. faecium reductions for use in food safety plans.
KW - Corn Starch
KW - Hurdle
KW - Hydrogen peroxide
KW - Ring dryer
KW - Sulfur dioxide
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UR - http://www.scopus.com/inward/citedby.url?scp=85212937934&partnerID=8YFLogxK
U2 - 10.1016/j.jfp.2024.100432
DO - 10.1016/j.jfp.2024.100432
M3 - Article
C2 - 39675632
AN - SCOPUS:85212937934
SN - 0362-028X
VL - 88
JO - Journal of Food Protection
JF - Journal of Food Protection
IS - 1
M1 - 100432
ER -