Journal of food protection最新文献

Although bench-scale studies have shown that superheated steam is effective for microbial inactivation on surfaces, commercial systems in the hands of human operators have not been evaluated. The first aim of this study was to characterize the temperature of stainless-steel surfaces treated with a commercial unit. The geometric center of the stainless-steel surface was treated with superheated steam at 400°C from a fixed position. Surface temperatures exceeded 300°C at the impingement point during 5 min exposure but decreased as surface thickness and distance increased. Ambient temperature (23.5, 12.8, 4°C) negatively impacted surface temperatures. Next, we evaluated the thermal inactivation of spot-inoculated Enterococcus faecium NRRL B-2354 on stainless steel surfaces. Inactivation of E. faecium decreased from 9.6 ± 0.1 log CFU/cm² after 10 s of treatment at the point of impingement to 2.8 ± 0.7 log CFU/cm² after 10 s of treatment at a distance 4.6 cm away from the impingement point (p<0.05). Finally, we assessed the effects of training on manual operation by human subjects. Human subjects (N=24) who completed trainings were asked to treat inoculated stainless-steel surfaces. While training improved manual operation of the unit and microbial inactivation of E. faecium (p<0.05), the highest average reduction achieved by human subjects was only 3.6 ± 1.3 log CFU/cm². These findings suggest that the tight radius of high surface temperatures around the nozzle limits the effectiveness of manually operated superheated steam units for microbial inactivation. Thus, equipment design improvements are needed to ensure uniform treatment and adequate surface sanitation.

Food waste caused by microbial spoilage poses negative economic and environmental impact at a global level. Alicyclobacillus acidoterrestris is a spore-forming, thermophilic bacterium that can cause spoilage in shelf-stable apple juice by producing off-odor compounds, including guaiacol. This study investigated the efficacies of natural glycolipid (NG), a novel antimicrobial, extracted from fungal fermentation, in controlling vegetative cells and spores of A. acidoterrestris in apple juice during storage at 25^°C and 45^°C. Apple juice was inoculated with vegetative cells or spores of A. acidoterrestris, and supplemented with 0, 10, 50 or 100 ppm NG. Half of the samples were subjected to heat treatment at 185^°F (85^°C) and the other half were not. Samples were stored at 25^°C or 45^°C for 28 days with samplings on day 0, 1, 3, 7, 14, 21, and 28. The minimum inhibitory concentration of NG was 4 and 8 ppm against spores and vegetative cells, respectively. The minimum bactericidal concentration of NG varied between strains, but was much higher than 100 ppm, which is the maximum recommended concentration for NG in juice and beverage products. During the 28-day storage, all tested concentrations of NG completely inhibited growth and outgrowth of A. acidoterrestris vegetative cells and spores at 45^°C, while the effect of NG was masked at 25^°C. Results also showed heating had some inhibitory effects against vegetative cells but not spores of A. acidoterrestris. In conclusion, we find NG suitable for inhibiting growth of A. acidoterrestris in shelf-stable apple juice.

Significant volumes of foods are traded between countries and this trade brings with it opportunities for foodborne hazards to cross borders and pose a public health risk. The Competent Authority in the importing country has a duty to protect its population from these foodborne hazards. Due to the high volumes of imported food as well as World Trade Organization requirements, border checks need to be prioritized in a risk-based manner. This represents an enormous practical challenge to which efficient solutions are required. This paper describes an approach to risk categorization and ranking of imported Foods of Non-Animal Origin on a food/country of origin/hazard (combination) basis. Combinations were scored using data on product characteristics, hazard characteristics and import volumes, with weightings applied following external consultation. The described approach differs from most others in that it categorizes and ranks microbiological, mycotoxin and chemical hazards with a single approach and on the same scale, allowing for meaningful comparison between the combinations. The output is a risk categorization, a relative risk ranking and a heat map, all of which provide information that can be used alongside other data by risk managers when prioritizing interventions at the border.

In the United States, the Food and Drug Administration (USFDA) prohibits distribution of fruit that is dropped from the plant and contacts the ground during harvest. This includes fruit which contacts the ground while attached to the plant, called "drooping" fruit. In the Southeastern US, tomato and pepper are trellised and grown on plastic mulch. The objective of this study was to obtain bacterial transfer rates from a nonpathogenic Escherichia coli GFP inoculated on plastic mulch (black and white) to fruit (tomatoes and peppers) that contact the ground by being dropped (at heights of 30, 60, or 120 cm) or by drooping (contact times of 1 h or 24 h) in the field during the summer season in Georgia, USA. Plastic mulch was surface inoculated with E. coli (10⁶ CFU/64 cm²) and after drying, populations were reduced by > 2-3 log CFU/64 cm². Once inoculum was dry, the fruit was either dropped from different heights through a PVC pipe or placed back onto the mulch in its initial resting place. The mean log percent transfer of E. coli from plastic mulch to dropped tomato and pepper fruit was -2.00 to 0.46 (0.01% to 2.88%). Mean log percent transfer rates of E. coli to drooping fruit were between -0.83 to 0.01 (0.15% to 1.02%), with no significant differences in transfer within crop types between treatments of plastic mulch color or contact time. Field environmental conditions throughout the experiment such as ambient air temperature, relative humidity, UV_AB radiation intensity, and surface temperature of plastic likely affected the rates of bacterial transfer. While other studies have evaluated bacterial survival and transfer from mulch to fruit in a laboratory setting, the present study addresses knowledge gaps in bacterial transfer during drooping and dropping incidents in the field when fruit contacts plastic mulch, providing results that have potential to inform future regulatory guidance for produce harvest and handling.