Microbial Quality and Histamine Producing Microflora Analysis of the Ice Used for Fish Preservation

Abstract

The aim of the present study was the estimation of the microbiological quality of ice used for fish preservation. Samples of flake ice, produced either from potable or seawater were collected monthly during a 12 month period and were examined for total heterotrophic count (THC) at 378C and 58C, total and fecal coliforms, enterococci, Pseudomonas spp., staphylococci, fungi, Vibrio spp., and histamine producing bacteria (HPB). THC at 378C was higher than the IPIA limit in 15% of the samples (9/60). In 91.67% of the samples (55/60) at least one fecal coliform colony was counted, with three of them (5%) exhibiting counts larger than 100 CFU/100g. All samples tested positive for enterococci, with 6 samples (10%) exhibiting counts greater than 100 CFU/ 100g. From the 282 isolates characterized as HPB, 24.10% were Pseudomonas spp. (n 5 67), 20.86% belonged to Enterobacteriaceae (n 5 58) and 19.42% were Staphylococcus spp. (n 5 54). Therefore, the ice used for fish preservation can be a potential source of microbial contamination, particularly of HPB; ice production from safe potable water should be practiced in order to safeguard public health. PRACTICAL APPLICATIONSIce is used extensively for fish preservation, providing an easy and cost effective way to control temperature of stored fish. Ice is a possible vehicle of pathogens contaminating the fish. The present research provides insight in the potential microbial contamination of fish by ice. Factors such as the nature of the water (potable water, seawater) used for ice production and the ice production process (small scale production at the retail store, production in an ice facility) were examined. Also, the involvement of ice as source of histamine producing bacteria was assessed based on the isolation, identification and enumeration of histamine producing bacteria in the examined ice samples. Therefore the results of this study provide useful data that can be applied to minimize the microbial burden of fish due to contaminated ice, to lengthen fish storage life and to avoid pathogen transmission to the consumers.

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

“…A bar consumption was simulated, with different drink systems, in order to estimate the effectiveness of the ice cubes to transfer pathogenic agents to consumers, and the results indicated a consistent risk reduction due to alcohol, CO 2 , pH and antibacterial ingredients. Thus, although several studies have been conducted in the last 2 years on the microbiological quality of packaged food ice (Awuor et al 2016;Economou et al 2017;Gaglio et al 2017;Hampikyan et al 2017;Lee et al 2017), focussing deep attention on the quality of water and transformation process, this study provides evidence and deepens previous findings (Gaglio et al 2017) on the effective risk related to the most common mode of consumption of contaminated ice. Furthermore, the findings evidenced several criticisms related to the food ice cube production, indicating the need to better investigate the hygiene of the water and equipment used, the transformation process applied, and storage/transport conditions.…”

“…Staphylococci were also found at a high percentage (34%) of the on-site packaged ice samples produced in South California analyzed by Lee et al (2017), and in 19.42% of flake ice samples used for fish preservation analyzed by Economou et al (2017). Economou et al (2017) also detected Pseudomonas spp. in 24.10% of ice samples.…”

Biosensing the Histamine Producing Potential of Bacteria in Tuna

“…A histamine biosensor may be also useful to detect also the activity of histidine decarboxylase that has been formed before tuna are frozen, which remains stable in frozen fish and can be reactivated after thawing (Visciano et al, 2014). In de-frozen fish, the number of viable bacteria can be reduced without affecting the activity of the enzyme that has been released into the flesh (Kanki et al, 2007; Economou et al, 2016), thus the measurement of HDC activity in the fish samples might be not always directly correlated with the number of HPB. More recently a histamine amperometric biosensor that is based on the use of antibody-antigen interaction (immunosensor) was developed to provide higher specificity (Dong et al, 2017).…”

Yeasts and moulds contaminants of food ice cubes and their survival in different drinks

“…The survival of micro-organisms in ice cubes has been the object of several very recent studies (Awuor et al 2016;Economou et al 2017;Gaglio et al 2017;Hampikyan et al 2017;Lee et al 2017). In general, the resistance of micro-organisms to water freezing temperatures is strictly dependent on their cytoplasm membrane.…”