Table 3.

Detection of nonproteolytic C. botulinum types B, E, and F by quantitative PCR analysis in sous vide-processed products with a high inoculum level (5.3 log CFU/kg) after storage at 4 and 8°C until sell-by date and 7 days after sell-by date

Product no. (recommended shelf life in days)No. of PCR-positive samples/no. of samples analyzeda
Sell-by date1 wk after sell-by date
4°C8°C4°C8°C
1 (14)1/3 (0.74; F)3/3 (1.91 ± 2.01; E)1/3 (2.18; E)3/3 (1.93 ± 1.75; E)b
2 (30)3/3 (0.80 ± 0.16; E, B)3/3 (0.55 ± 0.23; E)0/30/3
3 (21)0/32/3 (1.01; E)1/3 (0.41; B)2/3 (0.60; E)
4 (14)0/30/30/30/3
5 (10)2/3 (0.41; E, F)2/3 (0.41; E)0/30/3
6 (30)0/30/31/3 (0.41; E)0/3
7 (9)2/3 (0.41; E)1/3 (0.41; E)3/3 (1.70 ± 1.43; E)2/3 (1.50; E)
8 (21)3/3 (1.36 ± 0.79; E)3/3 (0.97 ± 0.79; E)b 0/30/3b
9 (21)1/3 (0.90; E, B)0/30/30/3
10 (21)0/30/30/30/3
11 (21)0/30/30/31/3 (0.41; E)
12 (21)0/30/32/3 (1.19; E)3/3 (0.94 ± 091; E)
13 (21)2/3 (1.54; E)1/3 (0.41; E)3/3 (1.41 ± 1.58; E)1/3 (1.04; E)
14 (30)0/30/30/30/3
15 (21)0/20/30/30/3
16 (21)0/30/30/30/3
  • a Data in parentheses are mean MPN log CFU per kilogram in PCR-positive samples (standard deviation of the cell counts is reported if more than two parallel samples were positive) and the serotype(s) detected, in diminishing order.

  • b One sample contained botulinum neurotoxin.