According to recent literature, delivering chilled Meals on Wheels to seniors increases food quality and safety. The purpose of this study was to determine the acceptability and/or feasibility of a cook-chill delivery system for participants in the Maimonides Geriatric Centre Meals on Wheels program in Montreal, Quebec. The authors also evaluated whether the meal was eaten upon delivery, documented where the meal was stored if consumption was delayed, determined what cooking/heating appliances were used and if the recipients were capable of heating up their meals, and assessed preferences for receiving chilled versus hot meals. Upon receiving the meal, 89% of the 60 seniors did not eat it immediately. Those who ate the meal later stored it in the refrigerator. All had some appliance available to heat the delivered meal; 55% used a microwave. Approximately 75% did not object to receiving meals chilled. The majority of recipients did not require delivery of hot meals, as most delayed consuming the meal until later in the day. Other meal-delivery program planners can use these findings when deciding if a cook-chill system is appropriate for their client populations.
Intensified aquaculture includes the use of antimicrobials for disease control. In contrast to the situation in livestock, Escherichia coli and enterococci are not part of the normal gastrointestinal flora of fish and shrimp and therefore not suitable indicators of antimicrobial resistance in seafood. In this study, the diversity and phenotypic characteristics of the bacterial flora in raw frozen cultured and wild-caught shrimp and fish were evaluated to identify potential indicators of antimicrobial resistance. The bacterial flora cultured on various agar media at different temperatures yielded total viable counts of 4.0 × 10(4) to 3.0 × 10(5) CFU g(-1). Bacterial diversity was indicated by 16S rRNA sequence analysis of 84 isolates representing different colony types; 24 genera and 51 species were identified. Pseudomonas spp. (23% of isolates), Psychrobacter spp. (17%), Serratia spp. (13%), Exiguobacterium spp. (7%), Staphylococcus spp. (6%), and Micrococcus spp. (6%) dominated. Disk susceptibility testing of 39 bacterial isolates to 11 antimicrobials revealed resistance to ampicillin, amoxicillin-clavulanic acid, erythromycin, and third generation cephalosporins. Resistance to third generation cephalosporins was found in Pseudomonas, a genus naturally resistant to most ß-lactam antibiotics, and in Staphylococcus hominis. Half of the isolates were susceptible to all antimicrobials tested. Results indicate that identification of a single bacterial resistance indicator naturally present in seafood at point of harvest is unlikely. The bacterial flora found likely represents a processing rather than a raw fish flora because of repeated exposure of raw material to water during processing. Methods and appropriate indicators, such as quantitative PCR of resistance genes, are needed to determine how antimicrobials used in aquaculture affect resistance of bacteria in retailed products.
G. N. Gabrichevsky Moscow Research Institute of Epidemiology and Microbiology, Federal Service for Surveillance on Consumer Rights Protection and Human Wellbeing, Moscow, Russia.
We developed a technological accessory bacteriophage-based preparation and a method for phage-mediated bioprocessing for elimination of pathogenic microorganisms from the surface of fresh fish and for prolongation of the shelf-life of chilled hydrobionts. Specimens of rainbow trout (Salmo irideus) served as the objects of the study carried out at a fish-processing plant in the Republic of Karelia. The specimens were decontaminated by a bacteriophage cocktail containing six original virulent phage strains characterized by their pheno- and genotypical properties. A new method of biodecontamination (plunging the rainbow trout for 30 sec into a solution of bacteriophage cocktail (bacteriophage titers =108 PFU/ml) delayed bacterial degradation of hydrobionts by 3 days. The use of the new method for decontamination of food half-products - phage-mediated bioprocessing - promoted preservation of the initial ecological purity, nutritive value, and taste of the products and prolonged their shelf-life in comparison with the actual standards.
Behavior of Salmonella spp., Listeria monocytogenes, and Staphylococcus aureus in Chouriço de Vinho, a dry fermented sausage made from wine-marinated meat.
Portuguese chouriço de vinho is made by drying coarsely minced meat and fat that has been previously marinated with wine (usually red), salt, and garlic for 1 to 2 days at a low temperature (4 to 8 °C). This procedure may improve the microbiological safety of the product. The aim of this study was to evaluate the behavior of three pathogens in this product, Salmonella spp., Listeria monocytogenes, and Staphylococcus aureus, to establish the minimum period of drying and maturation necessary to render safe products. The pathogens were inoculated in the chouriço de vinho batter. A factorial design was used to study the following variables in the fermentation process: (i) the presence or absence of an indigenous Lactobacillus sakei starter culture; (ii) the presence or absence of fermentable carbohydrates; and (iii) the salt level (1.5 or 3%). The samples were analyzed 24 h after the preparation of the batter (at stuffing); after 7, 15, and 30 days of drying; and after 30 days of storage at 4 °C under vacuum. Under all of the conditions studied, the levels of the three pathogens decreased during the drying period. In the early stages of drying, the addition of L. sakei starter culture and/or carbohydrates resulted in lower levels of gram-positive pathogens. After 15 days of drying, populations of all pathogens decreased by ca. 2 log in all samples. At that sampling time, L. monocytogenes was undetectable in the chouriço de vinho with L. sakei starter culture and carbohydrates. The mean count of S. aureus after 15 days of drying was below 1 log CFU/g. After 30 days of drying, no pathogens were detected. The drying period could be shortened to 15 days when considering only the gram-positive pathogens studied and the use of a starter culture and carbohydrates. Due to the low infective dose of Salmonella spp., the product should be considered safe after 30 days, when this pathogen became undetectable.
Biological activity was examined on Alaska pollack sikhae produced with 4 treatments (by irradiating at 5 or 10 kGy, or by adding either 0.1 or 0.3% of chitooligosaccharide), compared with control (2-step fermentation only) during fermentation at -2 degrees C. The extracts (500 ppm level) of sikhae had antimicrobial activities against 4 different strains of food poisoning bacteria such as Staphy. aureus, B. subtilis, B. cereus, and L. monocytogenes. Antioxidative activity (EDA(50), 11.55 mg/mL) in control group increased with time up to 60 days of fermentation but decreased thereafter, while those levels in other products were kept within 10.60-18.30 mg/mL ranges during fermentation. Inhibitory activity of angiotensin-I converting enzyme (ACE) (IC(50), 1.51-2.89 mg/mL) in all products was observed during fermentation except at 0 day. Inhibitory activity of xanthine oxidase (XO) (IC(50), 0.65-0.87 mg/mL) in all products also increased with time up to 30 days of fermentation. Without irradiating or adding of chitooligosaccharide, Alaska pollack sikhae showing biological activities was enough by 2-step fermentation and storage at -2 degrees C only.
A family cluster of three cases of type E botulism were identified in south-east France in September 2009. The suspected food source of infection was a vacuum packed hot-smoked whitefish of Canadian origin purchased by the family during a visit to Finland and consumed several weeks later in France on the day prior to symptom onset. No leftover fish was available to confirm this hypothesis. Vacuum packed hot-smoked whitefish has previously been associated with cases of type E botulism in multiple countries, including Finland, Germany, the United States and Israel.
Minimally processed spinach has been recently associated with outbreaks of foodborne illnesses. This study investigated the effect of commercial minimal processing of spinach on the coliform and Escherichia coli counts and the prevalence of E. coli O157:H7, Salmonella, Shigella spp., and Listeria monocytogenes on two types of spinach before and after minimal processing. A total of 1,356 spinach samples (baby spinach, n = 574; savoy spinach, n = 782) were collected daily in two processing plants over a period of 14 months. Raw spinach originated from nine farms in the United States and three farms in Canada. Overall, the proportion of samples positive for coliforms increased from 53% before minimal processing to 79% after minimal processing (P 0.1) was observed. E. coli O157:H7 and Shigella spp. were not isolated from any of the samples. Salmonella and L. monocytogenes were isolated from 0.4 and 0.7% of samples, respectively. Results demonstrate that commercial minimal processing of spinach based on monitored chlorine washing and drying may not decrease microbial load on spinach leaves as expected. Further research is needed to identify the most appropriate measures to control food safety risk under commercial minimal processing of fresh vegetables.
This paper discusses an outbreak of trichinosis that occurred in 1998 in Montgomery County, Ohio, and the investigation that followed. The outbreak was associated with consumption of bear meat from a hunt in Ontario, Canada. The person who had the index case had eaten two bear burgers that were cooked rare in a microwave oven. Bear meat from the same hunt later was consumed by 15 other people at a church supper and an additional 13 people who did not attend the supper. Of the 15 attendees at the church supper who ate the bear meat, seven developed illness consistent with Trichinella infection (attack rate about 47 percent). An additional seven people attended the supper but did not eat the bear meat and did not become ill. Having eaten bear meat at the church supper was associated with an increased risk of illness (p = .05). Inadequate cooking of the bear meat resulted in the transmission of live trichinae. The 13 other people who ate the bear meat but did not attend the supper reported no illness. A total of eight people, including the person with the index case, met the case definition for trichinosis. Adequate cooking of the bear meat or consumption of uninfected portions of the meat was probably the protective factor for those who did not become ill after consuming the bear meat.
