The antimicrobial effects of ozonated water in a recirculating concurrent reactor were evaluated against four gram-positive and four gram-negative bacteria, two yeasts, and spores of Aspergillus niger. More than 5 log units each of Salmonella typhimurium and Escherichia coli cells were killed instantaneously in ozonated water with or without addition of 20 ppm of soluble starch (SS). In ozonated water, death rates among the gram-negative bacteria--S. typhimurium, E. coli, Pseudomonas aeruginosa, and Yersinia enterocolitica--were not significantly different (P > 0.05). Among gram-positive bacteria, Listeria monocytogenes was significantly (P < 0.05) more sensitive than either Staphylococcus aureus or Enterococcus faecalis. In the presence of organic material, death rates of S. aureus compared with L. monocytogenes and E. coli compared with S. typhimurium in ozonated water were not significantly (P > 0.05) affected by SS addition but were significantly reduced (P < 0.05) by addition of 20 ppm of bovine serum albumin (BSA). More than 4.5 log units each of Candida albicans and Zygosaccharomyces bailii cells were killed instantaneously in ozonated water, whereas less than 1 log unit of Aspergillus niger spores was killed after a 5-min exposure. The average ozone output levels in the deionized water (0.188 mg/ml) or water with SS (0.198 mg/ml) did not differ significantly (P < 0.05) but were significantly lower in water containing BSA (0.149 mg/ml).

Protozoan parasites can survive under ambient and refrigerated storage conditions when associated with a range of substrates. Consequently, various treatments have been used to inactivate protozoan parasites (Giardia, Cryptosporidium, and Cyclospora) in food, water, and environmental systems. Physical treatments that affect survival or removal of protozoan parasites include freezing, heating, filtration, sedimentation, UV light, irradiation, high pressure, and ultrasound. Ozone is a more effective chemical disinfectant than chlorine or chlorine dioxide for inactivation of protozoan parasites in water systems. However, sequential inactivation treatments can optimize existing treatments through synergistic effects. Careful selection of methods to evaluate inactivation treatments is needed because many studies that have employed vital dye stains and in vitro excystation have produced underestimations of the effectiveness of these treatments.

This study was conducted to investigate the growth of microorganisms, including pathogenic bacteria such as Cronobacter sakazakii and Bacillus cereus, in Sunsik beverages made of water, milk, soymilk, or honey-water during storage at room temperature. Prepared Sunsik beverages were stored at room temperature and the growth of total aerobic counts, Escherichia coli/coliforms, and yeast and mold were measured. Also, samples inoculated with a cocktail of C. sakazakii or B. cereus spores were stored at room temperature and their growths were determined during storage. Populations of total aerobic counts and coliforms significantly increased with increasing storage time at room temperature, which resulted in higher than 8 log and 7 log after 24 h in all samples except for the honey-water sample, respectively. Levels of total aerobic counts and coliforms were significantly lower in the honey-water sample than in the other samples after 6 and 9 h of storage, respectively. Initial populations of C. sakazakii and B. cereus ranged from 0 to 1 log CFU/mL, respectively, and these populations significantly increased with increasing storage time at room temperature. Therefore, populations of C. sakazakii and B. cereus were approximately 7 to 8 log CFU/mL after 24 h of storage. However, after 12 and 9 h of storage, there were significant differences in levels of C. sakazakii and B. cereus between the honey-water sample and the other samples, respectively. Based on these results, the addition of honey can inhibit microbial growth in Sunsik beverages; however, the best way to avoid pathogen infection would be to consume Sunsik beverages as soon as possible after preparation.

1. The effects on food intake and weight gain of offering broiler chickens (2 to 7 weeks of age) dry food, wet food, wet food containing whey, whey as drinking liquid and combinations of two of these were studied in 5 experiments. 2. Wet feed generally improved both weight gain and feed efficiencies significantly. Feeding whey also improved weight gain and feed conversion efficiency, but whey offered as a drinking fluid had an adverse effect on broiler performance. 3. When whey was offered both as drinking liquid and added to the food it had a deleterious effect. 4. When whey was offered from 4 or 6 weeks of age, it had a better effect than when offered from 2 weeks of age. 5. There was better performance when whey in the drinking water was diluted and/or offered on alternate days or half-days. 6. Broilers allowed to choose between wet and dry feed when water was freely available chose mostly dry feed; in the absence of drinking water they chose mostly wet food. Birds offered water and liquid whey avoided whey completely. 7. It is concluded that whey can be used in diets for broiler chickens by incorporating it in the food as long as drinking water is offered ad libitum. Whey may be offered as a drink if the food is mixed with 1.8 times its weight of water but it is better to dilute the whey with an equal volume of water whether it is added to food or given as drink. Good results can also be obtained when undiluted whey is offered alternately with water, either in half-day or full-day periods.

Strains of Salmonella spp. with resistance to antimicrobial drugs are now widespread in both developed and developing countries. In developed countries it is now increasingly accepted that for the most part such strains are zoonotic in origin and acquire their resistance in the food-animal host before onward transmission to humans through the food chain. Of particular importance since the early 1990s has been a multiresistant strain of Salmonella typhimurium definitive phage type (DT) 104, displaying resistance to up to six commonly used antimicrobials, with about 15% of isolates also exhibiting decreased susceptibility to ciprofloxacin. Mutations in the gyrA gene in such isolates have been characterised by a PCR LightCycler-based gyrA mutation assay, and at least four different mutations have been identified. Multiple resistance (to four or more antimicrobials) is also common in the poultry-associated pathogens Salmonella virchow and Salmonella hadar, with an increasing number of strains of these serotypes exhibiting decreased susceptibility to ciprofloxacin. Multiple resistance is also being found in other serotypes in several other European countries, and has been associated with treatment failures. For Salmonella typhi, multiple drug resistance is now the norm in strains originating in the Indian subcontinent and south-east Asia. Such multiresistant strains have been responsible for several epidemics and some of these have been associated with contaminated water supplies. Furthermore, an increasing number of multiresistant strains of S. typhi are now exhibiting decreased susceptibility to ciprofloxacin, with concomitant treatment failures. In developed countries antimicrobial resistance in zoonotic salmonellas has been attributed to the injudicious use of antimicrobials in food-producing animals. It is hoped that the application of Codes of Practice for the use of such agents, which have been prepared by the pharmaceutical industry in response to widespread international concern about the development of drug resistance in bacterial pathogens, will now result in a widespread reduction in the incidence of drug-resistant salmonellas in food production animals and humans on an international scale.

Salmonella can survive for extended periods of time in low-moisture environments posing a challenge for modern food production. This dangerous pathogen must be controlled throughout the production chain with a minimal risk of dissemination. Limited information is currently available describing the behavior and characteristics of this important zoonotic foodborne bacterium in low-moisture food production environments and in food. In our study, the phenotypes related to low-moisture survival of 46 Salmonella isolates were examined. Most of the isolates in the collection could form biofilms under defined laboratory conditions, with 57% being positive for curli fimbriae production and 75% of the collection positive for cellulose production, which are both linked with stronger biofilm formation. Biocides in the factory environment to manage hygiene were found to be most effective against planktonic cells but less so when the same bacteria were surface dried or present as a biofilm. Cellulose-producing isolates were better survivors when exposed to a biocide compared with cellulose-negative isolates. Examination of Salmonella growth of these 18 serotypes in NaCl, KCl, and glycerol found that glycerol was the least inhibitory of these three humectants. We identified a significant correlation between the ability to survive in glycerol and the ability to survive in KCl and biofilm formation, which may be important for food safety and the protection of public health.

The synthesis of new chitin derivatives through ultrasound-assisted treatment of the chitin with 1-azido-3-chloropropan-2-ol under Green Chemistry conditions is described. This is the first example of ultrasound-assisted polymer analogues transformation of chitin unaccompanied by noticeable backbone degradation or deacetylation. The obtained water-soluble azido chitin derivatives are characterized by high antibacterial activity, which is comparable with that of commercial antibiotics ampicillin and gentamicin. At the same time, they were demonstrated almost identical in vitro toxicity as unmodified chitin and chitosan. The antibacterial activity of the obtained polymers is mainly provided by azido moiety in their macromolecules. The conjugation of azido moiety to chitin backbone strongly diminishes the toxicity of the azido pharmacophore, but preserves its antibacterial properties. The most potent chitin derivative was used for the film coating of Ricotta cheese samples. This food coating proved to be efficient for the prolongation of shelf life of Ricotta cheese.

: The influence of temperature (T) and water activity (a w) on the growth rate (μ) of seven moulds (Alternaria alternata, Aspergillus flavus, Cladosporium cladosporioides, Mucor racemosus, Penicillium chrysogenum, Rhizopus oryzae and Trichoderma harzianum) was assessed in suboptimal conditions. Firstly, the dependence of fungal growth on temperature, at a w 0.99, was modelled through an approach described previously for bacteria. A dimensionless growth rate variable: μ dᵢₘα=μ/μ ₒₚₜα depended on the following normalised temperature: T dᵢₘ=(T−T ₘᵢₙ)/(T ₒₚₜ− T ₘᵢₙ) according to a power function: μ dᵢₘα=[T dᵢₘ] ᵅ , where α was an exponent to be estimated. Secondly, the same approach was used to describe the influence of a w on fungal growth, at the respective optimum temperatures for each mould. Similarly, μ dᵢₘᵦ=μ/μ ₒₚₜᵦ depended on the following normalised water activity: a wdᵢₘ=(a w−a wₘᵢₙ)/(a wₒₚₜ−a wₘᵢₙ) according to a power function: μ dᵢₘᵦ=[a wdᵢₘ]ᵝ. Results show: (i) for each mould, the α-value is significantly less than the β-value, confirming that water activity has a greater influence than temperature on fungal development; (ii) the α-values and the β-values depend on the mould; (iii) the α-value is less than 1 for the mesophilic mould A. flavus, whereas the other moulds are characterised by higher α-values ranging from 1.10 to 1.54; (iv) the mesophilic A. flavus exhibits a low β-value, 1.50, compared to the hydrophilic T. harzianum, β=2.44, while β-values are within the range (1.71–2.37) for the other moulds. Journal of Industrial Microbiology & Biotechnology (2002) 28, 311–315 DOI: 10.1038/sj/jim/7000248

Food safety issues and increases in food borne illnesses have promulgated the development of new sanitation methods to eliminate pathogenic organisms on foods and surfaces in food service areas. Electrolyzed oxidizing water (EO water) shows promise as an environmentally friendly broad spectrum microbial decontamination agent. EO water is generated by the passage of a dilute salt solution (approximately 1% NaCl) through an electrochemical cell. This electrolytic process converts chloride ions and water molecules into chlorine oxidants (Cl2, HOCl/ClO-). At a near-neutral pH (pH 6.3-6.5), the predominant chemical species is the highly biocidal hypochlorous acid species (HOCl) with the oxidation reduction potential (ORP) of the solution ranging from 800 to 900 mV. The biocidal activity of near-neutral EO water was evaluated at 25 °C using pure cultures of Escherichia coli, Salmonella typhimurium, Staphylococcus aureus, Listeria monocytogenes, and Enterococcus faecalis. Treatment of these organisms, in pure culture, with EO water at concentrations of 20, 50, 100, and 120 ppm total residual chlorine (TRC) and 10 min of contact time resulted in 100% inactivation of all five organisms (reduction of 6.1-6.7 log10 CFU/mL). Spray treatment of surfaces in food service areas with EO water containing 278-310 ppm TRC (pH 6.38) resulted in a 79-100% reduction of microbial growth. Dip (10 min) treatment of spinach at 100 and 120 ppm TRC resulted in a 4.0-5.0 log10 CFU/mL reduction of bacterial counts for all organisms tested. Dipping (10 min) of lettuce at 100 and 120 ppm TRC reduced bacterial counts of E. coli by 0.24-0.25 log10 CFU/mL and reduced all other organisms by 2.43-3.81 log10 CFU/mL.

We examined the hypothesis that histidine is a regulator of short-term food and water intake in rats and that this control is through histidine's action as a precursor for histamine. The primary objectives were to measure food and water intake after histidine monohydrochloride monohydrate (His-HCl) given by intragastric (IG) and intraperitoneal (IP) routes of administration and to measure feeding and drinking responses to histidine when given after blockade of the histaminergic pathway by chlorpheniramine (CPA) and alpha-fluoromethylhistidine (FMH). Eight experiments were conducted using a back-to-back design. Rats were given treatment by IP or IG administration, and food and water intake was measured during time periods of 0-1, 1-2, 2-3 and 3-14 h. Histidine consistently reduced food intake with the sensitivity to IP much greater than to the IG route. The effect of histidine given by IP or IG on water intake was similar, generally causing an increase at least in the first hour. Histidine's action was not accounted for by its energy, pH or nitrogen content. Because FMH, which blocks the enzyme converting histidine to histamine, partially reversed the effect of histidine on food and water intake, those results support the hypothesis that histidine regulates food and water intake, at least in part, through its precursor control of histamine.