Biogenic amines have been reported in a variety of foods, such as fish, meat, cheese, vegetables, and wines. They are described as low molecular weight organic bases with aliphatic, aromatic, and heterocyclic structures. The most common biogenic amines found in foods are histamine, tyramine, cadaverine, 2-phenylethylamine, spermine, spermidine, putrescine, tryptamine, and agmatine. In addition octopamine and dopamine have been found in meat and meat products and fish. The formation of biogenic amines in food by the microbial decarboxylation of amino acids can result in consumers suffering allergic reactions, characterized by difficulty in breathing, itching, rash, vomiting, fever, and hypertension. Traditionally, biogenic amine formation in food has been prevented, primarily by limiting microbial growth through chilling and freezing. However, for many fishing based subsistence populations, such measures are not practical. Therefore, secondary control measures to prevent biogenic amine formation in foods or to reduce their levels once formed need to be considered as alternatives. Such approaches to limit microbial growth may include hydrostatic pressures, irradiation, controlled atmosphere packaging, or the use of food additives. Histamine may potentially be degraded by the use of bacterial amine oxidase or amine-negative bacteria. Only some will be cost-effective and practical for use in subsistence populations.

During the global 2020 COVID-19 outbreak, the advantages of online food delivery (FD) were obvious, as it facilitated consumer access to prepared meals and enabled food providers to keep operating. However, online FD is not without its critics, with reports of consumer and restaurant boycotts. It is, therefore, time to take stock and consider the broader impacts of online FD, and what they mean for the stakeholders involved. Using the three pillars of sustainability as a lens through which to consider the impacts, this review presents the most up-to-date research in this field, revealing a raft of positive and negative impacts. From an economic standpoint, while online FD provides job and sale opportunities, it has been criticized for the high commission it charges restaurants and questionable working conditions for delivery people. From a social perspective, online FD affects the relationship between consumers and their food, as well as influencing public health outcomes and traffic systems. Environmental impacts include the significant generation of waste and its high carbon footprints. Moving forward, stakeholders must consider how best to mitigate the negative and promote the positive impacts of online FD to ensure that it is sustainable in every sense.

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Processes by which fecal bacteria enter overland flow and their transportation state to surface waters are poorly understood, making the effectiveness of measures designed to intercept this pathway, such as vegetated buffer strips, difficult to predict. Freshly made and aged (up to 30 days) cowpats were exposed to simulated rainfall, and samples of the cowpat material and runoff were collected. Escherichia coli in the runoff samples were separated into attached (to particles) and unattached fractions, and the unattached fraction was analyzed to determine if the cells were clumped. Within cowpats, E. coli grew for 6 to 14 days, rather than following a typical logarithmic die-off curve. E. coli numbers in the runoff correlated with numbers inside the cowpat. Most of the E. coli organisms eroded from the cowpats were transported as single cells, and only a small percentage (about 8%) attached to particles. The erosion of E. coli from cowpats and the state in which the cells were transported did not vary with time within a single rainfall event or over time as the cowpats aged and dried out. These findings indicate that cowpats can remain a significant source of E. coli in overland flow for more than 30 days. As well, most of the E. coli organisms eroded from cowpats will occur as readily transportable single cells.

Abstract:The importance and challenges presented by Bacillus spores in the food industry are briefly outlined with a focus on Bacillus cereus. The structure and the mechanism of resistance exhibited by Bacillus spores are described, and the steps involved in their germination are included. Novel technologies, using no or only mild heat treatments, to inactivate Bacillus spores are covered, including ultraviolet radiation, pulsed electric field, and high-pressure processing, both as stand-alone techniques or techniques as part of a hurdle approach.

The luxS gene of Lactobacillus reuteri 100-23C was amplified by PCR, cloned, and then sequenced. To define a physiological and ecological role for the luxS gene in L. reuteri 100-23C, a luxS mutant was constructed by insertional mutagenesis. The luxS mutant did not produce autoinducers AI-2 or AI-3. Complementation of the luxS mutation by a plasmid construct containing luxS restored AI-2 and AI-3 synthesis. In vitro experiments revealed that neither the growth rate, nor the cell yield, nor cell survival in the stationary phase were compromised in the luxS mutant relative to the wild type and complemented mutant. The ATP content of exponentially growing cells of the luxS mutant was, however, 65% of that of wild-type cells. Biofilms formed by the luxS mutant on plastic surfaces in a bioreactor were thicker than those formed by the wild type. Biofilm thickness was not restored to wild-type values by the addition of purified AI-2 to the culture medium. In vivo experiments, conducted with ex-Lactobacillus-free mice, showed that biofilms formed by the mutant strain on the epithelial surface of the forestomach were approximately twice as thick as those formed by the wild type. The ecological performance of the luxS mutant, when in competition with L. reuteri strain 100-93 in the mouse cecum, was reduced compared to that of a xylA mutant of 100-23C. These results demonstrate that LuxS influences important ecological attributes of L. reuteri 100-23C, the consequences of which are niche specific.The proximal region of the gastrointestinal tracts of rodents, pigs, chickens, and horses is inhabited by a Lactobacillus population. These bacteria adhere to, and proliferate on, the surface of nonsecretory epithelia present in the forestomachs, pars oesophagea, crops, and nonglandular stomachs of mice and rats, pigs, chickens, and horses, respectively (7,32,39). These epithelial associations can be termed biofilms because the bacteria appear to be encased in carbohydrate material and layers of bacterial cells several cells thick can be demonstrated in stained cryosections on the surface of proximal gut epithelia (7,24). Shed from these biofilms, lactobacilli can be detected throughout the gut of the animal, including in the large bowel (23).Lactobacillus reuteri strain 100-23 is an autochthonous inhabitant of the rodent gut. Recent molecular biological studies have begun to unravel the molecular mechanisms that enable this bacterial strain to reside in the guts of mice (34,35). These studies have shown that L. reuteri 100-23 and the murine gut together provide an excellent paradigm to study the ecologically important characteristics, at the molecular level, of a gram-positive bacterial species that can form an epitheliumassociated biofilm and of coping with ecological competition in the large bowel environment (34,35).Several examples of the ability of bacterial cells to alert their kindred to increasing cell density (quorum sensing) have been described (17). Typically, bacterial cells produce a small extracellular signal molecu...