The microbiological quality of Slovenian raw milk from vending machines and their hygienic-technical conditions

Abstract

Purpose The purpose of this paper is to study the microbiological quality of raw milk delivered by 17 vending machines (VM) owned by different Slovenian milk producers. Design/methodology/approach For the determination of hygiene-technical conditions of VM, an observation list that included criteria for estimation of hygiene-technical suitability was made. A total of 51 milk samples were collected in three different seasons. The swabs and the cleaning liquid (eluates) of dispensing nozzles and chambers were also sampled. The main groups of microorganisms were determined by colony count technique according to international standards in all collected samples. Findings The aerobic colony count was higher than 100,000 CFU/mL in 20 (39.2 per cent) of milk samples. Its mean value was 4.8 log10 CFU/mL. The mean values of Enterobacteriaceae, psychrotrophic microorganisms, lipolytes, proteolytes, yeasts and moulds together, coagulase-positive staphylococci and somatic cell count were 3.3 log10 CFU/mL, 4.1 log10 CFU/mL, 3.2 log10 CFU/mL, 3.9 log10 CFU/mL, 2.2 log10 CFU/mL, 2.8 log10 CFU/mL and 5.3 log10 cells/mL, respectively. E. coli was found in 33.3 per cent of milk samples, while Listeria monocytogenes and antibiotics were not detected. The inner surface contamination of the dispensing nozzles and chambers was estimated in the range from 1.8 log10 CFU to 6.0 log10 CFU/cm2. The presence of detergents and disinfectants in supply valve eluates was determined in more than one-third of the samples. The hygienic-technical conditions of observed VM show some deviations from specified hygienic-technical requirements which could influence the safety of raw milk. Research limitations/implications The data about construction and the cleaning practice of VM, included in the experiment, were not available during the inspection facility. Originality/value In the paper the pathogenic and also the spoilage microorganisms in milk in the combination with hygienic conditions of inside surfaces of VM were studied.

Detection and Pulsed-Field Gel Electrophoresis Typing of Listeria monocytogenes Isolates from Milk Vending Machines in Croatia

“…In Italy, 0.5% of milk from vending machines was positive for L. monocytogenes and characterized by low contamination levels [14]. Torkar et al [15], in Slovenia, reported that the quantity of L. monocytogenes in raw milk was below 10 cfu/mL. However, it should be noted that in the present study, using a molecular procedure, a higher number of Listeria-positive samples was detected compared to the standard reference method.…”

The investigation of suitability of raw milk consumption from vending machines in Croatia

“…The share of milk samples with a somatic cell count in excess of 400 000 cell/mL was also lower, at 21.6% (Godic Torkar et al, 2017). The criteria of 100 000 cfu/mL was met by 91% samples of raw milk from vending machines in Slovakia (Vietoris et al, 2016).…”

“…The quality of the physicochemical parameters of raw milk from vending machines according to available literature sources was studied by Stetca et al (2014), Tremonte et al (2014) andCroatian Food Agency (2016) while its hygienic quality and suitability during storage in vending machine has been studied by more authors Giacometti et al (2012aGiacometti et al ( , 2012b, Bianchi et al (2013aBianchi et al ( , 2013b, Giacometti et al (2013), Stetca et al (2014), Tremonte et al (2014), Dalzini et al (2016), Croatian Food Agency (2016), Godic Torkar et al (2017 and Kunova et al (2017).…”