Table 4. Biological decay of bacteria under different relative humidity (RH) and temperature (Temp).
| Bacteria | RH levels involved (%) | Temp levels involved (°C) | H/L[a] | Extreme RH for decay (%) | Extreme Temp for decay (°C) | Decay | Survival [b] | Half-life | Reference |
|---|---|---|---|---|---|---|---|---|---|
| Chlamydia pneumoniae | 5, 50, 95 | 8.5, 15, 25, 35 | H | 50 | 35 | — | 0% (1.5) | — | (Theunissen et al., 1993) |
| L | 95 | 15, 25 | — | >10%* (5.5) | — | ||||
| 32–87 | 15, 30 | H | <50% | 30 | — | — | 3 min | (Wathes et al., 1986) | |
| L | High RH | 15 | — | — | 83 min | ||||
| E. coli (lyophilized) | 20*–100* | 26.5 | H | 50*, 90*–100* | 26.5 | — | 0.9*–2*% (30) | — | (Cox, 1970) |
| L | 20* | 26.5 | — | 20*–30*% (30) | — | ||||
| Flavobacterium | 25, 45, 65, 85, 99 | 24 | H | 99 | 24 | 2.6% min−1 | — | — | (Ehrlich et al., 1970a) |
| L | 85 | 24 | 1.3% min−1 | — | — | ||||
| 85, 100 | –40,–18, –2, 24, 29, 38, 49 | H | 85 | 49 | <0.01% min−1 | — | — | (Ehrlich et al., 1970a) | |
| L | 100 | −40,–18 | 4.7% min−1 | — | — | ||||
| Legionella pneumophila strain 74/81 | 30, 60, 90 | 20 | H | 60 | 20 | - | <1% (120) | — | (Dennis and Lee, 1988) |
| L | 90 | 20 | — | >10*% (120) | — | ||||
| Mycoplasma laidlawii | 10, 25, 40, 50, 60, 75, 90 | 27 | H | 40 | 27 | — | <1% (300) | — | (Wright et al., 1968b) |
| L | 10, 90 | 27 | — | 10*–100*% (60) | — | ||||
| Mycoplasma gallisepticum | 10, 25, 40, 50, 60, 75, 90 | 27 | H | 50, 60 | 27 | — | 0% (300) | — | (Wright et al., 1968b) |
| L | 10 | 27 | — | 100%* (60) | — | ||||
| Mycoplasma pneumoniae | 10, 25, 30, 40, 50, 60, 75, 80, 90 | 27 | H | 60, 80 | 27 | — | 0% (240) | — | (Wright et al., 1968a) |
| L | 10 | 27 | — | 50% (240) | — | ||||
| Pasteurella multocida | 28, 40, 59, 79 | 22.6 | H | 79 | 22.6 | — | 2.1% (45) | — | (Thomson et al., 1992) |
| L | 40 | 22.6 | — | 8.9% (45) | — | ||||
| Pasteurella tularensis | 0*–90* | 26.8 | H | 50* | — | — | 0.2*–0.3*% (15) | — | (Cox and Goldberg, 1972) |
| L | 90* | — | — | 100%* (15) | — | ||||
| 20*–95* | — | H | 55 | — | — | 0.2*–1*% (15) | — | (Cox, 1971) | |
| L | 95* | — | — | >50%* (15) | — | ||||
| Pasteurella tularensis (lyophilized) | 0*–90* | 26.8 | H | 81 | — | — | 0.4*–0.6*% (15) | — | (Cox and Goldberg, 1972) |
| L | 0* | — | — | >10*% (15) | — | ||||
| 20*–95* | — | H | 75 | — | — | 0.01*−0.02*% (15) | — | (Cox, 1971) | |
| L | 20* | — | — | 10*–20*% (15) | — | ||||
| Pseudomonas fluorescens | 23, 39, 60, 79 | — | H | 79 | — | — | 0.01*–0.1*% (60) | — | (Handley and Webster, 1993) |
| L | 39, 60 | — | — | 1*–3.2*% (60) | — | ||||
| Rhizobium meliloti | 30, 50, 70, 95 | 20 | H | 30 | 20 | — | 0.1*–1*% (300) | — | (Won and Ross, 1969) |
| L | 50, 70, 95 | 20 | — | >10*% (300) | — | ||||
| Sarcina lutea | 1/3, 23/27, 45/52, 73/76, 88/96 | 15 | H | 1/3 | 15 | 0.346 log% h−1 | — | — | (Lighthart, 1973) |
| L | 45/52 | 15 | 0.001 log% h−1 | — | — | ||||
| Serratia marcescens | 40, 97 | 25 | H | 40 | 25 | — | 2% (32) | — | (Hess, 1965) |
| L | 97 | — | — | 100% (32) | — | ||||
| 45/52, 73/76, 88/96 | 15 | H | 45/52 | 15 | 0.368 log% h−1 | — | — | (Lighthart, 1973) | |
| L | 73.0/75.5 | 15 | 0.057 log% h−1 | — | — | ||||
| Staphylococcus no. 1600 | 39, 75 | — | H | 75 | — | 0.0189 log min−1 | — | — | (Strasters and Winkler, 1966) |
| L | 39 | — | 0.0037 log min−1 | — | — | ||||
| Streptococcal L-Forms | 20, 40, 60, 80 | 27 | H | 40 | 27 | — | 0% (30) | — | (Stewart and Wright, 1970) |
| L | 20 | 27 | — | >10*% (240) | — |
*Estimated readings from figures. [a]H = highest biological decay of airborne microorganisms (i.e., worst survival and shortest half-life time). L = lowest biological decay of airborne microorganisms (i.e., optimal survival and longest half-life time). [b] In brackets is the time span (in minutes) between which survival rate corresponds to.