Field handling conditions of raw milk sold in vending machines: experimental evaluation of the behaviour of Listeria monocytogenes, Escherichia coli O157:H7, Salmonella Typhimurium and Campylobacter jejuni

Figures & data

Table 1 Strains used for raw milk inoculation.

	Strain
Listeria monocytogenes	ATCC 6994
	Wild strain isolated from raw milk DUP 1042 (IZSLER)
	Wild strain isolated from raw milk DUP 1045(IZSLER)
Campylobacter jejuni	ATCC n. 49943
	Wild strain isolated from raw milk FED 2010/31(DSMV)
	Wild strain isolated from raw milk FED 2010/111(DSMV)
Escherichia coli O 157:H7	ATCC 35150
	Wild strain isolated from raw milk DUP 3064(IZSLER)
	Wild strain isolated from raw milk DUP 18588(IZSLER)
Salmonella Typhimurium	ATCC 6994
	Wild strain isolated from raw milk 2010/67492 (IZSLER)
	Wild strain isolated from raw milk 2010/67498 (IZSLER)

Table 2 Pathogenic microbial population count during storage at 4°C and at variable temperatures (mean±SD Log CFU mL1 of 9 data: 3 replicates ×3 batches).

		Listeria monocytogenes		Escherichia. coli O 157:H7		Campylobacter jejuni		Salmonella Typhimurium
Phase	Sampling, total time	4°C±0.5	Variable conditions	4°C±0.5	Variable conditions	4°C±0.5	Variable conditions	4°C±0.5	Variable conditions
Inoculation	T0, 0 h	2.23±0.03	2.18±0.03	2.40±0.09	2.14±0.02	1.92±0.06	1.92±0.06	1.98±0.19	1.88±0.09
Transport to the vending machine°	T1, 5 h	2.29±0.41	2.30±0.11	2.42±0.05	2.28±0.14	1.82±0.25	1.98±0.01	1.77±0.12	1.94±0.10
Storage in the vending machine#	T2, 27.5 h	2.35±0.20	2.45±0.24	2.17±0.16	3.15±0.30	1.74±0.13	1.97±0.07	1.78±0.11	2.00±0.01
Transport home§	T3, 28 h	2.41±0.06	2.50±0.13	2.28±0.09	2.90±0.02	1.84±0.06	1.96±0.07	1.51±0.07	2.72±0.24
Home storageˆ	T4, 96 h	2.61±0.02	3.25±0.31	2.10±0.13	3.97±0.28	1.72±0.07	1.28±0.18	1.85±0.25	3.20±0.06
After boiling	T5, 96 h	nd	nd	nd	nd	nd	nd	nd	nd

° Time and temperature of incubation in each phase during storage at variable temperatures: °5 h at 7°C±0.5;

# 22.5 h at 11°C±0.5;

§ 30 min at 30°C±0.5 air temperature;

ˆ 68 h at 12°C±0.5;

nd, not detected.