Validation of the CompactDry "Nissui" BC for Enumeration of Bacillus cereus in a Variety of Foods: AOAC Performance Tested MethodSM 092201.

Background: The CompactDry "Nissui" BC is a ready-to-use dry media sheet using a chromogenic medium with selective agents for the detection and enumeration of Bacillus cereus in products after incubation at 30 ± 1°C for 24 ± 2 h.

Objective: The CompactDry "Nissui" BC method was validated to achieve AOAC Performance Tested MethodsSM certification.

Method: The performance of the CompactDry "Nissui" BC was compared to that of ISO 7932:2004 for 10 matrixes, including panna cotta, double cream, dried baby food, dried vegetable soup mix, seafood sticks, salmon pâté, sliced ham, pork liver pâté, ham and cheese sandwich, and Caesar pasta salad with chicken and bacon.

Validation of the CompactDry "Nissui" YMR for Enumeration of Yeasts and Molds in a Variety of Foods: AOAC Performance Tested MethodSM 092002.

Background: The CompactDry "Nissui" YMR is a ready-to-use dry media sheet using a chromogenic medium with selective agents for the detection and enumeration of yeasts and molds in products after incubation at 25 ± 1°C for 3 days.

Objective: The CompactDry "Nissui" YMR method was validated in order to achieve AOAC Performance Tested MethodsSM certification.

Method: The performance of the CompactDry "Nissui" YMR was compared to that of ISO 21527-1:2008 for 10 matrixes including cooked prawns, deli vegetable salad, tuna pâté, fermented yogurt drink, spinach and ricotta quiche, egg custard tarts, fruit and vegetable smoothie, cream cheese, egg salad sandwich, and deli pasta salad.

Soleris®Enterobacteriaceae for the Detection of Enterobacteriaceae in Select Foods: AOAC Performance Tested MethodSM 121901.

Background: Soleris®Enterobacteriaceae is a growth-based, automated method for detection of Enterobacteriaceae in food.

Objective: A study was conducted to validate the Soleris method for detection of Enterobacteriaceae in select foods (pasteurized milk, yogurt, mozzarella cheese, ice cream, dried milk, pasteurized liquid egg, frozen cooked chicken, deli ham, lettuce, and dry dog food) at a threshold of ≥ 10 CFU/g of product.

Methods: Inclusivity and exclusivity of the Soleris method were assessed by testing 55 and 38 target and non-target bacterial strains, respectively.

MC-Media Pad EC for Enumeration of Escherichia coli and Coliforms in a Variety of Foods.

Background: Standard coliform count methods require preparation of agar, the use of pour-plate technique, the overlay of agar, and in some cases, the transfer of suspect colonies to broth medium for confirmation. The MC-Media Pad EC for enumeration of Escherichia coli and coliforms is a ready-to-use dehydrated sheet medium with no agar preparation, no spreader, and no confirmation step required.

Objective: Using a paired study design, the MC-Media Pad EC was compared with standard method ISO 4832:2006.

MC-Media Pad CC for Enumeration of Total Coliforms in a Variety of Foods.

Background: Standard coliform count methods require the preparation of agar, the use of the pour-plate technique, the overlay of agar, and in some cases, the transfer of suspect colonies to broth medium for confirmation. The MC-Media Pad CC for the enumeration of coliforms is a ready-to-use dehydrated sheet medium with no agar preparation, no spreader, and no confirmation step required.

Objective: Using a paired study design, the MC-Media Pad CC was compared to standard method ISO 4832:2006 for 10 matrixes including raw ground pork, raw chicken, cream, cream cheese, ready-to-cook vegetable mix, vegetable juice, cooked prawns, crab pâté, ham sandwiches, and cooked rice.

MC-Media Pad ACplus™ for Enumeration of Aerobic Counts in a Variety of Foods.

The MC-Media Pad ACplus™ is a dry, rehydratable film medium for the enumeration of aerobic bacterial colonies. The performance of the method in a variety of foods was compared to that of U.S.

MC-Media Pad SA (Sanita-kun SA) for the Enumeration of in a Variety of Foods.

MC-Media Pad SA (formerly known as Sanita-kun SA) is a dry rehydratable film medium for the enumeration of Staphylococcus aureus. The performance of the method in a variety of foods was compared with that of ISO 6888-1:1999, Microbiology of Food and Animal Feeding Stuffs - Horizontal Method for the Enumeration of Coagulase-Positive Staphylococci (Staphylococcus aureus and Other Species) - Part 1: Technique Using Baird-Parker Agar Medium. The validated matrixes included pastrami, a sliced cooked chicken roll, cooked prawns, cold-smoked salmon, pasta salad, sandwich spread, fresh uncooked pasta, infant cereal, custard, and raw-milk Brie cheese.

Membrane toxicity of antimicrobial compounds from essential oils.

Natural antimicrobial compounds perform their action mainly against cell membranes. The aim of this work was to evaluate the interaction, meant as a mechanism of action, of essential oil antimicrobial compounds with the microbial cell envelope. The lipid profiles of Escherichia coli O157:H7, Staphylococcus aureus, Salmonella enterica serovar Typhimurium, Pseudomonas fluorescens, and Brochothrix thermosphacta cells treated with thymol, carvacrol, limonene, eugenol, and cinnamaldehyde have been analyzed by gas chromatography.

Changes in membrane fatty acids composition of microbial cells induced by addiction of thymol, carvacrol, limonene, cinnamaldehyde, and eugenol in the growing media.

Major active compounds from essential oils are well-known to possess antimicrobial activity against both pathogen and spoilage microorganisms. The aim of this work was to determine the alteration of the membrane fatty acid profile as an adaptive mechanism of the cells in the presence of a sublethal concentration of antimicrobial compound in response to a stress condition. Methanolic solutions of thymol, carvacrol, limonene, cinnamaldehyde, and eugenol were added into growth media of Escherichia coli O157:H7, Salmonella enterica serovar typhimurium, Pseudomonas fluorescens, Brochothrix thermosphacta, and Staphylococcus aureus strains.

Use of survival analysis and Classification and Regression Trees to model the growth/no growth boundary of spoilage yeasts as affected by alcohol, pH, sucrose, sorbate and temperature.

This paper describes the application of a survival analysis model and a Classification and Regression Trees (CART) model to a data set comprising times to growth of a yeast cocktail inoculated into media simulating a fruit-based or alcoholic food or drink, and covering over 900 combinations of five environmental factors (alcohol, pH, sucrose, sorbate and temperature). Growth was determined as either the time to growth within a 150-day time period or as no-growth after 150 days. Models were developed which could either predict the likelihood of growth occurring within the 150 day period, or the time to grow, either in days or in one of three categories chosen to represent a rapid (1-14 days), medium (15-30 days) or slow (31-150 days) growth response.