Presence of pathogenic bacteria in ice cubes and evaluation of their survival in different systems

Abstract

In this study, 60 samples of ice cubes produced at different levels (domestic, restaurant and industrial facilities), within a restricted geographical area, were investigated for their general microbiological characteristics through the analysis of populations other than enteric bacteria. Total mesophilic bacteria were in the range 1.01 × 10 2 -9.55 × 10 3 , 3.12 × 10 2 -6.31 × 10 3 and 1.30 × 10 2 -3.99 × 10 3 CFU/ 100 mL of thawed ice from domestic freezer (DF), stock boxes (SB) for self-production performed with ice machines in bars and pubs, and from sales packages (SP) of industrial productions, respectively. Some DF and SP samples were negative for the presence of total psychrotrophic bacteria, showing that there are no specific microbial groups associated with ice. Pseudomonads were found in the majority of ice samples analyzed. The levels of contamination of the ice samples were significantly different among the three ice cube production levels. The samples produced at domestic level and those collected from bars and pubs were characterised by the highest cell densities. The colonies representative for the different bacterial morphologies were randomly picked up from plates, purified to homogeneity and subjected to the phenotypic and genotypic characterisation. Fifty-two strains representing 31 species of eight bacterial genera were identified, with the most numerous groups included in Pseudomonas, Staphylococcus, Bacillus and Acinetobacter. A consistent percentage of the microorganisms identified from ice are known agents of human infections, and their presence indicate an environmental contamination. In order to evaluate the effectiveness of the ice cubes to transfer pathogenic agents to consumers, a bar consumption was simulated with different drink systems added with ice cubes artificially contaminated with the strains found at dominant levels (Acinetobacter lwoffii ICE100, Bacillus cereus ICE170, Pseudomonas putida ICE224 and Staphylococcus haemolyticus ICE182), and the results showed a consistent reduction of bacterial risk due to alcohol, CO 2 , pH and antibacterial ingredients of vodka, whisky, Martini, peach tea, tonic water and coke.

Application of Hydrogen Peroxide to Improve the Microbiological Stability of Food Ice Produced in Industrial Facilities

“…For this reason, the application of disinfection methods is necessary to reduce the microbiological risks related to drinking water [3] and its transformation products. The product obtained directly from potable water through the application of the freezing process is referred to as "food grade ice" or most commonly "food ice" [4]; this product is generally available for consumption in the form of cubes [5]. After melting, food ice becomes potable water [6] and it has to satisfy the minimum requirements on the hygiene of foodstuffs [7].…”

“…Industrial food ice is produced worldwide using ice machines and is commercialized after packing in plastic bags. Often, the quality and safety of packaged food ice does not meet the hygienic standards requested for drinking water [8] and this is imputable to improper handling during production [9], post-production contamination by the transformation environment [4], and to the packaging [10]. As a result, several microorganisms can be found in food ice, mainly intestinal bacteria [5,11,12], but also unicellular and filamentous fungi [13].…”

Food Hygiene Surveillance in Italy: Is Food Ice a Public Health Risk?

“…Worldwide food ice production has increased in recent years because of the high demand for ice cubes in public places such as bars, pubs and restaurants. Today, commercial ice production is estimated at around 500,000 tonnes per year in Europe and 5,600,000 tonnes per year in the United States [1]. Used in large quantities mostly in the summer, ice is useful in restorative and commercial activities for preparing cold drinks, and helps to maintain the cold chain that is very important for multiple foods, including fish and other foods eaten raw.…”

“…Many studies have investigated the microbiological quality of food ice and have confirmed its potential role as a vehicle for foodborne illnesses. In fact, Enterobacteriaceae, Enterococci and fungi have been isolated from ice in Italy [1,6,7]; total and faecal coliforms, Clostridium perfringens, Pseudomonas aeruginosa, Yersinia spp. and Salmonella spp.…”

Microbiological and chemical quality of ice used to preserve fish in Lisbon marketplaces

“…and Salmonella spp. (Falcão, Dias, Correa, & Falca, ); Pseudomonas , Staphylococcus , Bacillus , and Acinetobacter (Settanni et al, ); Hepatitis A virus (Beller, ); Norovirus (Khan et al, ) and Vibrio Cholera (Ries et al, ; Waturangi, Pradita, Linarta, & Banerjee, ). Several factors have been linked to microbiological contamination of ice, namely: use of contaminated water for its production (Lateef, Oloke, Kana, & Pacheco, ; Northcutt & Smith, ), storing conditions, unsanitary ice handling, production and transportation procedures, type of use and production equipment (Awuor, Thompson, Thompson, Liberda, & Meldrum, ; Gerokomou et al, ; Nichols & Gillespie, ; Wilson, Hogg, & Barr, ).…”