Table 1.

Effect of heat treatment on population densities of culturable bacteria and fungi in Allium plant-cultivated soils (cfu gram⁻¹ dry soil).

Rhizosphere soil	Microorganism	Heat treatment
		No treatment	40 °C	60 °C	80 °C	121 °C
Welsh onion	Bacteria
	Gram-negative	0.7–1.3 × 108	0.6–1.1 × 108	<2.8 × 106	ND	ND
	Gram-positive	0.7–1.0 × 108	5.0–9.7 × 107	2.0–3.9 × 107	1.9–3.5 × 107	ND
	Fungi	0.8–3.1 × 106	0.5–2.4 × 106	0.3–1.8 × 104	<1.5 × 102	ND
Onion	Bacteria
	Gram-negative	3.4–6.0 × 107	2.6–4.7 × 107	<1.9 × 106	ND	ND
	Gram-positive	4.0–6.7 × 107	2.1–3.0 × 107	2.0–3.0 × 107	2.3–2.7 × 107	ND
	Fungi	2.4–2.7 × 105	1.5–1.8 × 105	2.3–3.7 × 103	<2.3 × 102	ND

The culturable bacterial densities were estimated using 1/10 strength tryptic soy agar, and Gram reaction was determined using the KOH method. The culturable fungal densities were estimated using rose bengal-streptomycin agar. The experiment was repeated three times. ND: not detected.