Generally, the enumeration and isolation of food-borne pathogens is performed using culture-dependent methods. These methods are sensitive, inexpensive, and provide both qualitative and quantitative assessment of the microorganisms present in a sample, but these are time-consuming. For this reason, researchers are developing new techniques that allow detection of food pathogens in shorter period of time. This review identifies commercially available methods for rapid detection and quantification of Listeria monocytogenes, Salmonella spp., Staphylococcus aureus, and Shiga toxin-producing Escherichia coli in food samples. Three categories are discussed: immunologically based methods, nucleic acid-based assays, and biosensors. This review describes the basic mechanism and capabilities of each method, discusses the difficulties of choosing the most convenient method, and provides an overview of the future challenges for the technology for rapid detection of microorganisms.

In the 30 year time period that microwave ovens have been used in households, several studies have examined variables that influence temperatures and bacterial destruction achieved in foods heated by microwave energy. Factors of primary importance include both physical and chemical (product mass, density, specific heat, ionic content, dielectric properties) parameters. The majority of evidence indicates that microwaves inactivate microbes by thermal effects alone. Concern about the safety of microwave-heated foods has arisen because of the abbreviated thermal treatment that microwave heating affords, the potential for temperature abuse of microwavable products, and the risk of pathogen survival in foodservice cook/chill foods. Foodborne pathogens such as Listeria monocytogenes, Staphylococcus aureus and Salmonella spp. have been the focus of most studies of microwavable food safety, primarily because of their ubiquitous nature and prevalence in causing illness. The practical implications of the findings of both basic and applied studies of bacterial destruction within microwave-heated products are examined.

The popularity of farmers' markets continues to rise in the U.S.A. Raw poultry products sold at farmers' markets are of particular concern due to the United States Department of Agriculture inspection exemption status afforded to many poultry vendors. Whole chicken from farmers' markets and supermarkets in Pennsylvania were evaluated for the prevalence of Campylobacter spp. and Salmonella spp. and demonstrated that 28% (28/100) and 90% (90/100) of chicken from farmers' markets, 20% (10/50) and 28% (14/50) of conventionally processed organic, and 8.0% (4/50) and 52% (26/50) of nonorganic chicken, were positive for Salmonella spp. and Campylobacter spp., respectively. Additionally, among the 90% of Campylobacter spp.‐positive farmers' market poultry, 67% of rinses were enumerable, with a mean count of 1.6 log10 cfu/mL. The results from this study demonstrate the need to develop food safety training for poultry vendors at farmers' markets in order to improve the safety of these products for public consumption. Practical Applications The popularity of farmers' markets is increasing throughout the U.S.A. Vendors are selling numerous food products, including raw chicken, which is known to harbor Campylobacter spp. and Salmonella spp. As such, their control continues to be a priority during commercial chicken processing. However, no study has evaluated the presence of these pathogens in raw chicken sold at farmers' markets. The data collected in this study demonstrated that of the raw, whole chicken carcasses sampled from farmers' markets in Pennsylvania, 90 and 28% were contaminated with Campylobacter spp. and Salmonella spp., respectively. These results suggest that vendors could greatly benefit from food safety training and education to address antimicrobial interventions during processing. This study also demonstrates the rationale for further research into the safety of foods sold at farmers' markets. This information may also be useful to local and state regulatory officials responsible for food safety.

Inactivation of Escherichia coli and Listeria monocytogenes were investigated in buffer and milk upon treatment with ultrasound waves (USW). In addition, sonoprotective effect of milk components and ultrasound-induced changes in bacterial cells were investigated using scanning electron microscopy (SEM). Bacterial cells were added to phosphate buffer, whole milk, skim milk, or simulated milk ultrafiltrate (SMUF). To determine the sonoprotective effect of milk components, lactose (5%), casein (3%), or β lactoglobulin (0.3%) was added to SMUF. Samples were sonicated with 24 kHz pulse USW while maintaining the system temperature between 30 to 35 °C. Aliquots were drawn at set times during sonication and bacteria were enumerated by surface plating appropriate dilutions on selective and nonselective media plates. Escherichia coli exhibited significantly higher D values in whole (2.43 min) and skim milk (2.41 min) than phosphate buffer (2.19 min). Listeria monocytogenes also showed higher D values in whole (9.31 min) and skim milk (8.61 min) compared to phosphate buffer (7.63 min). Data suggest that milk exerts a sonoprotective effect on these bacteria. Escherichia coli exhibited a log-linear inactivation kinetics followed by tailing whereas L. monocytogenes showed 1st-order kinetics throughout. Among the milk components tested, presence of lactose in SMUF resulted in significantly higher D values than SMUF for both organisms suggesting that lactose was exerting a protective effect on bacteria. SEM images showed that USW caused mechanical damage to the cell wall and cell membrane of bacteria leading to their inactivation.